Ch 61a Stifle: CCL Flashcards

Question

What are the two options of meniscal release?

Answer 1

- Mid-body - Transection of caudal meniscotibial ligament No significant differences between the two! Meniscal release is similar to hemimeniscectomy in regards to meniscal function but less radical meniscal excision is associated with less disruption of chondrocytes

Answer 2

- goal of eliminating the wedge effect of the caudal horn during femorotibial subluxation. - been investigated in both in vivo and ex vivo experiments - accepted experimental model in dogs for inducing osteoarthritis - 50% decrease in contact area + 140% increase in the magnitude of pressure on the medial compartment of a cranial cruciate ligament–deficient stifle joint treated with a tibial plateau leveling osteotomy - significant caudal shift of load - supraphysiologic loading of articular cartilage > upregulation in synthesis and degradation of cartilage matrix > OA - combination of inflammatory and degradative mediators originating from the transected meniscus and biomechanical abnormalities from the loss of hoop tension play key roles - Meniscal release is equivalent to caudal hemimeniscectomy with regard to meniscal function, further supporting the importance of an intact functional unit - caudal hemimeniscectomy and total meniscectomy were investigated in vivo: secondary osteoarthritis induced after both types similar in terms of pathologic changes, but the less radical excision is associated with less disruption of chondrocyte metabolism - Incomplete meniscal regeneration can originate from the synovial membrane but not functional

Answer 3

- abnormal dynamic joint function likely plays a part in OA in CCL-deficient stifles kinematic - demonstrated that the CCL–deficient stifle joint remains more flexed throughout the gait cycle. - hip and tarsocrural joints respond by remaining more extended during the stance phase - study demonstrated a significantly increased cranial subluxation of the tibia (8 to 12 mm) during the stance phase of the gait. In most, subluxation was unchanged during the swing phase. - 2 years following, ~ 5 mm of cranial tibial translation was present at the terminal swing phase > The authors suggested intact medial meniscus reducing tibial subluxation as a secondary stabiliser - long-term joint instability leading to joint capsule fibrosis and meniscal injury may cause a reduction in static joint laxity - range of abduction and adduction of the stifle joint was nearly doubled at 2 months postoperatively and remained significantly increased at 2 years kinetic - analysis has revealed decreases in peak vertical forces and impulses -

Answer 4

Normal dogs have PVF of 70% of static BW on limb After CCLR: - 25% at 2 weeks - 32% at 6 weeks - 37% at 12 weeks

Answer 5

joint stability is maintained by: 1. synergism between the muscle forces responsible for stifle joint flexion and extension 2. cranial tibial thrust force 3. pull of the stifle flexor muscles of the thigh 4. passive restraints of the stifle joint (CCL + caudal pole of the medial meniscus) two major factors account for the joint compressive force between the tibia and the femur: direct forces of weight bearing and contraction of the gastrocnemius muscle magnitude of the cranial tibial thrust is dependent on: 1. magnitude of the joint compressive force (weight bearing and counteracted by the active and passive elements) 2. the slope of the tibial plateau joint reaction force during weight bearing is approximately parallel to the longitudinal axis of the tibia, and it can be resolved into a cranially directed shear force and a joint compressive force (perpendicular to the tibial plateau). Tibial plateau leveling results in a joint reactive force that is perpendicular to the tibial plateau. Thus, it can only be resolved into a joint compressive force; cranial tibial thrust is eliminated.

Answer 6

- total joint force (joint reaction force) is not parallel to the functional axis of the tibia as proposed by Slocum but, instead, is parallel to the patellar ligament Tepic theorized that under weight-bearing conditions: 1. force applied to the paw is not similar to the moment applied during the tibial compression test (as based in slocum). 2. Instead, force applied to the paw is parallel to the patellar ligament. 3. stabilization procedures should be aimed at leveling the tibial plateau perpendicular to the patellar ligament or altering the angle of the patellar ligament such that it is perpendicular to the tibial plateau joint reaction force is approximately parallel to the patellar ligament, resolved into a cranially directed shear force and a joint compressive force. Advancing the tibial tuberosity such that the patellar ligament is perpendicular to the tibial plateau neutralizes the cranial tibial thrust force.

Answer 7

- assumptions of both models is full muscle recruitment - balance between flexor and extensor muscles of the stifle joint may vary between individuals - TPLO and TTA are two-dimensional, and they do not consider the complex rotational stability of the stifle joint

Answer 8

1. traumatic avulsion of the femoral or tibial attachment 2. acute traumatic rupture secondary to excessive strain 3. progressive degeneration of unknown cause (partial or complete)

Answer 9

- skeletally immature animals, the attachment of ligament to bone by Sharpey's fibers may be stronger than the bone - an acute overload of the ligament, may result in avulsion from tibia, or femur - may be amenable to primary repair by reattachment (wire, screws) Epiphysiodesis - surgically induced premature union of the epiphysis with the diaphysis of the proximal tibia - to reduce the tibial plateau angle in skeletally immature dogs +/- augment primary repair of an avulsed - inserted into the center of the cranial intercondyloid area of the tibia and is oriented parallel to the tibial shaft - Correct placement of the Kirschner wire is confirmed by intraoperative fluoroscopy - Epiphysiodesis of cranial physis while the caudal aspect continues to grow > reduction of the TPA (as long as residual growth remains) - case series of 22 joints, a reduction in the tibial plateau angle of 4 degrees and improved or normal gait in 18 of 22 - Valgus deformity in 3 of 22 as the result of eccentric insertion

Answer 10

Epiphysiodesis Can cause valgus deformity as a result of eccentric insertion or angulation of the screw

Answer 11

- Excessive limb loading - traumatic hyperextension - excessive internal rotation - dramatic pain, joint effusion, severe lameness, and stifle joint instability are present. - injury usually results in a midsubstance “mop end” tear - RADS: severe effusion with no osteophytes

Answer 12

- etiopathogenesis of CCL disease, however; remains incompletely understood. A general consensus is that Abnormal biology and biomechanics interact and exacerbate one another by complex and largely unknown mechanisms, leading invariably to the development of osteoarthritis - concept of the joint being an organ is based on the interconnectedness of all tissues including cartilage, synovium, synovial fluid, menisci, cruciate, collateral ligaments and bone - During locomotion, cranial tibial trust seems to exhibit the strongest load which is counteracted by the CCL - central aspect is poorly vascularized, which often corresponds to area of initial ligament degeneration and rupture (Hayashi et al 2004) - CCL disease appears to be biphasic with a nearly silent initial phase that involves progressive degradation of the ligament followed by structural failure - Joint instability then perpetuates inflammatory and degenerative changes in a second phase of secondary OA (Cook 2010).

Answer 13

inflammation, ligament degradation or impaired synthesis of extracellular matrix and early cellular apoptosis. - some evidence that ligament failure is preceded by relatively silent but progressive **collagen matrix degeneration** of the intra-articular structures including the CCL (lack of collagen fiber maintenance and loss of fibroblasts from core) - demonstrated a decrease in material properties with **aging**. - The central part of the ligament may be especially vulnerable due to the **limited blood supply** of this area, especially once no longer encased by an intact synovium (Hayashi et al 2004). - **Cellular apoptosis** has been found in partially ruptured CCL, demonstrating that apoptosis and therefore abnormal ligament tissue is already present in the early stages - unanswered, however, as to what triggers and perpetuates these - **inflamed synovium** also plays an early and significant role in CCL disease - Kuroki et al (2011) research on synovial histology suggests that the innate immune system plays an important role in initiating and maintaining lymphoplasmacytic synovitis - Several studies on synovial fluid samples of dogs with CCLR have demonstrated **upregulation of enzymes, metabolites, and inflammatory cytokines consistent with OA** including IL-1, IL-6, IL8, and TNFb (de Bruin et al 2007

Answer 14

- **instability** intuitively plays a key role, other such as **anatomic abnormalities, muscle weakness, abnormal kinematics and altered contact areas** may precede instability as well as contribute to overall joint inflammation and tissue degeneration (Cook 2010, Kim et al 2009). - These may be due to underling genetics, nutrition or traumatic events (Cook et al 2020) - increased strain in the CCL result in simultaneous contraction of the caudal thigh muscles and relaxation of the quadriceps muscle group > **protective mechanism**, obesity and/or poor physical condition may mitigate these - correlate factors such as a **steep tibial plateau angle conformation, high body weight, breed and neutered status** to increased risk of developing CCL disease (Duval et al 1999). - smaller dogs—those weighing less than 22 kg—tend to be affected later in life than larger dogs - **neutering** increases the prevalence of cranial cruciate ligament injury - variation in the material properties reported bewteem greyhound and rottweiler - Though evidence for a direct causal link for these risk factors, including for tibial plateau angle, is lacking - **Early osteoarthritic changes** are already identifiable in stifle joints with little or no instability, such as in cases of partial rupture (Agnello et al 2021). - kinematic changes following the functional loss of CCL alter loading of the articular cartilage and result in the development of OA (Griffin and Guilak 2005). - Second-look arthroscopic evaluation of dogs following TPLO confirm progressive cartilage changes in majority of dogs despite surgery (Hulse et al 2010). - Intervention in the early stages of CCL disease, i.e. partial rupture, has shown an improved long-term outcome as compared to complete tear (Shimada et al 2020),

Answer 15

- Obesity of poor fitness may mitigate the protective effects of the reflex responses to CCL mechanoreceptors - Progressive mechanical overload due collagen degeneration (decreased birefringence and elongation of crimping in remaining collagen fibrils) - Immune-mediated - Acquired loss of blood supply TPA - study: breed and body weight were not significant, whereas age and tibial plateau angle did influence contralateral cranial cruciate ligament rupture, with increasing age being associated with increasing survival of the contralateral ligament. - another study, tibial plateau angle was not found to be a useful predictor of contralateral rupture in dogs - no association in labs

Answer 16

highest - Rottweiler, - Newfoundland, - Staffordshire Terrier lowest - Dachshund, - Basset Hound, - Old English Sheepdog before 2 years of age - Neapolitan Mastiff, - Akita, - Saint Bernard, - Rottweiler, - Mastiff, - Newfoundland, - Chesapeake Bay Retriever, - Labrador Retriever, - American Staffordshire Terrier. Female dogs have an increased prevalence

Answer 17

22 - 54% | median time of 947 days in one study

Answer 18

- Historical findings include pelvic limb lameness that is worse following exercise or periods of rest - pain response with flexion and extension of the stifle joint, variable crepitus - quadriceps muscle atrophy - medial periarticular hypertrophy > medial buttress formation - Joint effusion - abnormal “sit test" (Disorders of the hock may also result in this) cranial drawer test - creates craniocaudal tibial translation by applying a force to the tibia - young dogs > physiologic translation (puppy drawer). differentiated from pathologic instability by the sudden stop after 3 to 5 mm of motion. - severe muscle wasting, a small amount of cranial drawer may be present partial CCL - craniomedial band is torn > drawer is present in flexion only because the intact caudolateral part is taut in extension. - caudolateral part is torn > no cranial drawer is present because the craniomedial band is taut in both flexion and extension - effusion/pain > likely partial CCL even if no draw - radiography, magnetic resonance imaging (MRI), and arthroscopy can be used to confirm tibial compression test - creates stifle joint compression that results in a cranial tibial thrust force - if CCL no intact, tibial subluxation occurs - maintain stifle joint extension - tarsocrural joint is alternately flexed and extended, simulating contraction of the gastrocnemius

Answer 19

- osteoarthritis - confirm stifle pathology in challenging cases of partial tear - rule out fracture or neoplasia - loss or effacement of the infrapatellar fat pad shadow by a soft tissue opacity - osteophyte and/or enthesophyte > femoral trochlear ridges, the tibial condyles, the proximomedial margin of the tibia (collateral ligaments) apex of the patella, narrowing of the intercondylar notch - subchondral sclerosis - examination of the contralateral stifle is recommended - joint effusion and osteophytosis of the contralateral stifle joint were found to be risk factors for rupture of the contralateral

Answer 20

- minimally invasive, low-morbidity - thorough evaluation of synovium, joint pouches, articular cartilage, cruciate ligaments, and menisci. - benefits of illumination and magnification, - allow manipulation of soft tissues such as cruciate ligaments and menisci - gold standard of joint evaluation: accurate diagnostic tool that enables direct probing and viewing - In early partial tear, the normal fiber (crimp) pattern is lost and the ligament appears homogeneous, edematous, and palpably lax - proportion of torn fibers and laxity typically increase as the disease progresses. - Other findings: synovitis, cartilage fibrillation and eburnation, osteophytosis

Answer 21

Sensitivtiy 90% Specificity 92.9%

Answer 22

- 30-80% - higher in neutered - Isolated meniscal tears rare, reported in Boxers and working dogs and also with osteochondral lesions - medial meniscus - Radial tears of the lateral meniscus, most commonly tears involving the axial edge of the meniscus (axial fringe tears) - frequently identified at the time of diagnosis of CCL or later (Postliminary occur after Sx, Latent are present but not identified) - incidence of postoperative 2.8% to 27.8% > variation due to technique and/or the diagnostic approach - usually occurs within the first 6 months after surgery, ususally need sx risk factors - results of these studies are often contradictory and do not provide enough evidence - No association with breed, sex, or tibial plateau angle has been found - increased incidence in overweight dogs and in dogs with chronic and complete ccl - Most studies report an increased incidence of postoperative meniscal tears in dogs with intact menisci compared to dogs having undergone meniscal release and meniscectomy - postoperative tears: TTA 3x more likely than dogs treated with TPLO and 6x more likely than dogs treated with TightRope

Answer 23

- relates to abnormal motion of CCL–deficient joint - medial meniscus is firmly attached to the tibia > becomes entrapped between the femoral and tibial condyle during cranial tibial translation - role as a stabilizer increases its risk of failure - caudal horn may tear as a result of the shear stress applied to the longitudinal and radial fibers > longitudinal tear - combination of rotational and translational instability may cause pinching of the cranial pole of the lateral meniscus - different ligamentous constraints of the medial versus the lateral meniscus likely predispose the medial meniscus to greater risk of injury *surgery that neutralizing joint shear mitigates the wedge effect of the meniscus* - cadaveric study: intact CCL, cranial horn of the medial meniscus experienced the greatest force in extension, the caudal horn when in flexion. Transection of CCL led to a rise in mean force under both horns > Most under the caudal horn of the medial meniscus - organization of the collagen fibers helps define the type of mechanical failure occurring in the meniscus - proteoglycans are weaker in both compression and tension than the collagen fibers - compression of the meniscus produces circumferential tensile stress, the tissue will dissipate strain energy through fissure propagation perpendicular to the tensile stress. - This mechanism translates into a high incidence of longitudinal tears

Answer 24

77% radial tears of the axial edge of the lateral meniscus. Significance unknown

Answer 25

Postliminary - Tears which occur ofter the initial surgery Latent - Tears which are present at the time of the initial surgery but are not identified Incidence 2.8 - 27.8deg

Answer 26

- Meniscal tears are frequently encountered in cases of chronic cranial cruciate ligament - postliminary tear occurs, acute lameness may arise - audible clicking (or both), and pain are suggestive of meniscal tears - 100% presented with lameness, but only 27% of the dogs had an audible or palpable click. - sensitivity and specificity of a palpable meniscal click during physical examination were approximately 50% and 90%, respectively, with an overall diagnostic accuracy of 80% RADs - limited importance for the diagnosis - 46% incidence of meniscal mineralization was reported in 100 domestic short- and longhair cats, in the cranial horn of the medial meniscus and severe osteoarthritis - clinical significance in cats is unknown conflicting reports have described the benefits of MRI and (CT) arthrography MRI - normal meniscus a uniformly low signal on T1-W - high-field MRI in 11 large-breed, sensitivity of 100% and a specificity of 94% - sensitivity and specificity of 0.64 and 0.90, respectively, low-field MRI did not reach acceptable levels of diagnostic accuracy CT - sensitivity (13% to 73%) and specificity (57% to 100%) for meniscal lesions - large and displaced meniscal lesions are readily seen on CT arthrography - Lack of interpreter experience and poor contrast medium distribution in more chronic disease ultrasound - prospective study, this noninvasive technique - high sensitivity and specificity for dogs with severe meniscal tears, - dependence on operator experience

Answer 27

- Arthroscopy and arthrotomy - ex vivo study: Arthroscopy with probe had higher sensitivity and specificity than arthrotomy, - probing enhanced the sensitivity and specificity for both - craniomedial arthrotomy was most sensitive in CCL–deficient stifles - clinical study: probing during arthrotomy is useful for identifying otherwise latent tears - improved by using a stifle joint distractor

Answer 28

Overweight dogs Chronic and complete CCLR TTA 3x more likely vs TPLO TTA 6x more likely vs Tightrope

Answer 29

27% - Sensitivty 50% - Specificity 90%

Answer 30

9.6 times more likely with a complete tear

Answer 31

A: Intact B: Vertical longitudinal tear (occur parallel to the collagen fibers) C: Bucket Handle tear (most common, may be seen as multiple tears) D: Flap or oblique tear E: Radial tears (from the free inner edge of the meniscus toward the periphery, axial fringe tears) F: Horizontal tear (difficult to view or probe) G: Complex tear (in chronic cases and frequently as folded caudal horn) H: Degenerative tear

Answer 32

Stifle at 110-130 degrees External rotation and valgus stress

Answer 33

- **Caudal hemimeniscectomy** (for nonsalvageable injuries of the caudal horn, segmental, from caudal meniscotibial ligament to midbody ) - **Total meniscectomy** (for tears that extend most of meniscus and an intact rim cannot be preserved or ligamentous attachments are disrupted) - **Partial meniscectomy** (removal of damaged axial section while preserving cranial and caudal meniscotibial ligaments and peripheral rim)

Answer 34

Increase in contact stress a greater degree of osteoarthritis loss of stability

Answer 35

exposure - Exposure should be optimized using retractors and distraction - valgus and varus stress are required to view both menisci. - stable with partial CCLR the caudal pole of the medial meniscus may not be visible with arthrotomy > scope of caudal arthrotomy - position of the arthroscopy portals is important + appropriate debridement of the fat pad - portals should be located approximately where the tibial plateau axis intersects the patellar ligament - causing the tibia to subluxate cranially - irregularities on the surface and hooking or catching of the probe - Hooking of the probe at the periphery of the meniscus should be interpreted carefully because the edge of the caudal pole is only loosely attached

Answer 36

- arthroscopy provides better magnification and illumination. - ensure exposure and instrument portal positions are optimal - risk of iatrogenic articular cartilage damage - AIM: remove all pathologic tissue while preserving as much normal tissue as possible to maintain meniscal function - probe is used to progressively evaluate the torn tissue and the extent > axial edge and the meniscal surfaces - biomechanical function of the meniscus greatly depends on its peripheral tissue. (Loss of hoop stress) - meniscus-synovium junction should be preserved - Motorized shavers of small diameter (≤3.5- 2.5-mm in medium-size and larger dogs) - Resection of unstable meniscal fragments is important to prevent entrapment - piecemeal removal or en bloc resection - removed using suction, or they are flushed from the joint - punch, meniscal knife, beaver blade or Motorized shavers

Answer 37

- advocated in conjunction with TPLO to prevent the development of postoperative meniscal injuries - caudal meniscotibial ligament of the medial meniscus (caudal release) or at the midbody of the medial meniscus (central release) - Meniscal release allows the caudal horn of the medial meniscus to displace caudally, avoiding impingement - postoperative meniscal injuries are more likely caused by persistent instability (rotational or translational) or misdiagnosis - MRI STUDY: spared the caudal horn from entrapment and confirmed caudolateral displacement of the caudal horn after both types of meniscal release. suggest that releasing the meniscus should completely eliminate the risk of a postliminary injury. - late meniscal injury has been documented to occur despite meniscal release in some patients (dt poor technique or atent tear that progresses to a degenerated meniscus)

Answer 38

caudal release

Answer 39

- meniscal treatment is performed with a stabilization technique > Therefore difficult to isolate the clinical effects of meniscal treatment from those of the stabilization procedure **postliminary meniscal tears**, - the outcome after meniscectomy is excellent in the **short term** - 88% improvement, or return to normal status **meniscectomy** - prospective study: type of treatment of the meniscus may have a greater impact on clinical outcome than does the cranial cruciate ligament stabilization technique. Dogs diagnosed and treated for concurrent (i.e., tears identified during the original surgery) meniscal tears were 1.3 times more likely to have a successful long-term outcome than cases in which a concurrent tear was not identified - effect in the **long term** may be less favorable because of the progression of osteoarthritis - STUDY Innes: 50 months after surgery, dogs that had meniscal injury had higher scores for disability, inactivity, and stiffness than those without a meniscal injury - time to follow-up is a major factor in outcome after meniscectomy; Other studies suggest minimal difference in the short term after meniscectomy - conserving functional meniscal tissue is advantageous in the long term. - Innes and others provided good evidence that an intact meniscus plays a major role in the long-term function of dogs operated for cranial cruciate ligament insufficiency - conservative treatment is crucial for the lateral meniscus **meniscal release** - Short-term have been reported, but no long-term outcome studies - justified when the incidence of postliminary tears is unacceptably high - Because release is not always effective in preventing postliminary tears, caudal hemimeniscectomy may be a better to completely eliminate the risk - meniscal release is functionally equivalent to a caudal hemimeniscectomy > speculated may be a poor prognostic factor in the long term - available data support the use of meniscal release in conjunction with stabilization procedures with a high rate of postliminary meniscal injury, or when the prospect of a revision surgery is not acceptable for the owner. best strategy to decrease latent tears is to improve the accuracy of meniscal diagnosis - 4x more likely to occur in dogs treated by arthrotomy with no meniscal release than in dogs treated with arthroscopy with no meniscal release - Meniscal diagnosis can be improved by probing, magnification, illumination, retraction, and distraction - high rate of true postliminary meniscal tears may result from a stabilization technique (choose a Sx that protects meniscus best) - argued that the meniscus should be preserved at any cost, despite the risk of reoperation **Repair of the meniscus** - reported but the lack of outcome data difficult to provide clinical guidelines - Meniscal repair is limited to those tears located in the red-red (most peripheral) region of the meniscus

Answer 40

- techniques rely on periarticular fibrosis for long-term stability because the stability first created is relatively short lived - modification of the extracapsular technique reported by DeAngelis and Lau - lateral arthrotomy, assess intra-articular - damaged cranial cruciate ligament are removed because they may act as a source of continued inflammation (not proven) - joint is copiously lavaged with physiologic saline - craniodistal aspect of the lateral fabella articulates with the femur > suture placed slightly proximal to the fabella, in fibrous origin of lateral gastrocnemius muscle - proximal end of the tibia is exposed by incising the fascia overlying the cranial tibial muscle; one or two holes are drilled - limb is positioned at approximately 100 degrees of flexion - suture is tensioned adequately to neutralize the cranial drawer; it is not overtightened (decreased ROM and increased contact pressure in the joint) - stability is confirmed by a negative cranial drawer test and a negative tibial compression test - Mayo mattress pattern (vest over pants) or with another imbrication - echeck examination to assess stifle joint stability and limb use is performed 6 to 8 weeks - normal activity is encouraged during weeks 9 to 16 as the periarticular fibrosis matures

Answer 41

suture can be tensioned by: - hand with a square knot, a sliding (slip) knot, a self-locking knot - a tensioning device - suture can be secured by several square knots nylon leader line - superior to other types of nylon - recovers resting tension to a greater degree - higher failure load and greater stiffness - elongates less under a given load than nylon fishing line - biologically inert, low bacterial adherence, and is minimally affected by sterilization - strength of the line (pound test) is generally chosen to be at least equivalent to the body weight of the patient; however, optimal not been determined. - estimated load applied to the suture is 120 to 600 N Mechanical testing of knot type - metallic crimp: lower elongation, higher load at failure, greater stiffness, and greater initial loop tension compared to square knot - study: single self-locking knot + double self-locking knot compared with square knot, There was no difference in elongation among the knots, The self-locking knots were stronger and stiffer than the square loop types - interlocking loop had the greatest load at yield but also the greatest elongation at yield (which is detrimental to stifle joint stability)

Answer 42

- Ideally, isometric (i.e., the two points would remain equidistant during stifle joint range of motion). - because of the cam shape of the femoral condyle, and ligamentous and muscular constraints of the stifle, the axis of rotation of the femur relative to the tibia does not remain constant - complex rolling, sliding, and rotational motion of the femur with respect to the tibia > truly isometric does not exist strain analysis of femoral and tibial anchorage sites - traditional fabellotibial suture site [F1] and [T1] = least isometric - distal pole of the fabella [F2] paired with caudal wall of the extensor groove of the tibia [T3] = the most favorable - F2 and T3 require a bone tunnel or a bone anchor - radiographic analysis of the isometry confirms F2 amd T3 sites as being closest - Anchorage at nonisometric sites shown to result in suture loosening and tightening during stifle ROM in cadaveric study may lead to breakage/elongation (when tight) or instability (when loose) - variations in individual anatomy likely result in variations in isometric site location - non truely isometric > **quasi-isometric**

Answer 43

tightrope - minimally invasive - uses bone-to-bone anchorage via femoral and tibial tunnels - flat polyblend suture tape, braided ultra-high-molecular-weight polyethylene polyester (FiberTape) - secured with suture buttons - combines quasi-isometric suture anchorage with a high tensile strength suture material with low creep - STUDY: prospective clinical 6-month outcomes not different to TPLO - cadaveric STUDY: failure at a significantly greater number of cycles with the TightRope compared to other ex-cap, however: high loads still failed same Swivelock - flat polyblend suture tape, braided ultra-high-molecular-weight polyethylene polyester (FiberTape), and a knotless anchor system - placed at the quasi-isometric points F2-T3 - interference PEEK screw suture anchor eliminate knots and reducing the risk of intra-articular placement of suture material - elimination of the knot > less creep, which is a slow change in suture length under load - Retrospective STUDY: major complication rate of 7.3% and good to excellent long-term functional outcomes in all cases - mechanical STUDY: isolated loops of nylon leader vs polyethylene cord vs tape in bone tunnels or anchor. The anchor– tape, creep was not significantly different than the corresponding isolated prosthetic loops - used with great success in human joint stabilizing procedures **interference screw**: compression fixation device that relies on the screw threads to engage and compress the suture for fixation to bone

Answer 44

based on clinical examination, - satisfactory outcomes in 85.7% of 42 dogs - improvement in 87.5% and normal gait in 60% - another study 94.1% of dogs were clinically sound at a walk and trot - retrospective study: clinician assessment + force platform gait analysis, clinicians graded 14 of 18 dogs (77.7%) good - excellent and force platform gait analysis normal in 6 of 7 dogs (85.7%) force plate - prospective study: only 40% improved, and 15% returned to normal function - disparity between clinical exam and kinetic gait analysis highlights the superior accuracy of force platform gait analysis - rehabilitation group showed significantly higher peak vertical force and vertical impulse 6 months postoperatively compared with no rehab group + not significantly different from that of the normal limb - benefit of postoperative rehabilitation; massage, walking, and swimming twice daily during weeks 3 to 7 after surgery TPA - angle did not appear to have predictive value in terms of outcome in dogs with a TPA 18.5 degrees to 34.9 degrees Excap vs TPLO in prospective clinical trials - 80, random, Peak vertical force at a walk and trot was 6% and 11% higher and 93% vs 75% oweer satisfaction - osteotomy (n = 15) or excap (n = 23) compared to normal control (n = 79) using kinematic gait analysis: TPLO more symmetric limb loading than the lateral fabellotibial stabilization group, TPLO not different from those of the control group by 6 months to 1 year unlike excap group - authors concluded that dogs achieved normal limb loading faster in TPLO

Answer 45

- **17.4%** complications (63 of 363) - 7.2% required 2nd Sx - **higher rate of complications: high body weight and young age of the dog** - intraoperative 0.3% - Peroneal nerve deficits in 1 dog 0.3% - surgical site infection **3.9%** - incisional 8.8% (self-trauma, swelling and discharge, and bandage-related) - implant-related 2.8% (swelling and/or lameness) - Postliminary meniscal tear rate **15.2%** - **2%** required sx - 0% when meniscal release performed

Answer 46

- Fibular head is mobilized and advanced cranially - alters lateral collateral ligament, thereby preventing cranial drawer movement and internal rotation of the tibia - peroneal nerve should be identified and protected - small incision is made in the connective tissue between the peroneus longus muscle and the cranial tibial muscle - Syndesmosis between the fibular head and the tibia is identified - Two holes are drilled in the tibial crest cranial and distal to the fibular head, and a loop of 18 or 20 gauge stainless steel - fibular head is advanced cranially with the tibia held in external rotation, and a pin is placed - wire is looped over the pin in a figure of eight pattern Outcomes and Complications - initial report 49 of 71 stifle joints (69%) had excellent function - retrospective 91.7% to have good or excellent function, and force platform gait analysis normal in 0 of 5 dogs (0%) - experimental study: ranial drawer motion was not controlled, rotational instability was present, and significant radiographic progression of OA, at 10 months, 50% of dogs had postliminary medial meniscal tears - significant elongation of the ligament was evident 3 weeks after surgery - fibular fracture in 10 of 85 dogs (12.5%) - tearing of the LCL (2.5%) - postoperative instability (6%) - seroma formation

Answer 47

- long been advocated as a method of ACL repair in humans - ligament may be reconstructed with other biologic tissues (allograft or xenografts), synthetic materials, or a combination of synthetic and biologic materials (composite grafts) - Regardless of the tissue > all are avascular at the onset - incorporation requires revascularization and remodeling that takes ~ **20 weeks** to complete - initial phase of inflammation and graft necrosis, revascularization and cell repopulation, and graft remodeling. - grafts undergo necrosis, resulting in compromised mechanical properties. - protect the graft > ligament augmentation device (LAD) placed alongside the graft - Alternatively, a prosthesis instead, designed to permanently replace the ligament - interest in scaffolds into the knee (form a neoligament) - Few data in the clinical realm of veterinary surgery indicate the best material to use > copious experimental studies on animals in human literature - **substitute**: mimic not only the native anatomy but also biomechanical properties + must be fixed securely + permit tissue integration (replaces the native CCL) - **Prostheses**: permanently replace the native ligament + withstand all of the functional loads + resistant to subsequent wear and failure

Answer 48

autografts - bone–patellar tendon–bone, - hamstring tendon [semitendinosus and gracilis muscles], - quadriceps femoris muscle tendon, allografts - (all of the former) - Achilles tendon synthetics - Dacron, - silk, - ligament augmentation devices [LADs]

Answer 49

- There is no evidence as yet that reconstruction of the ACL reduces the incidence or progression of degenerative change in the knee, but early stabilization reduces the incidence of subsequent meniscal pathology - Most surgeons undertake the entire procedure arthroscopically, although incisions are needed for graft harvest, for femoral tunnel drilling or fixation in some techniques - Allograft: for revisions and primaries in patients greater than 35 years old as they avoid donor site morbidity; however, re-tear rate increases significantly in younger patient - Synthetic ligaments are not currently recommended for routine primary intra-articular reconstruction. - Wrapping of graft in Vancomycin soaked swab (5mg/ml), prior to implantation, has been shown to significantly reduce infection rates in ACL reconstruction surgery to approaching 0% graft types - Hamstring tendon: slightly higher re-tear rate when compared with BPTB, main complication being of damage to the infrapatellar branches of the saphenous nerve - BPTB has a higher rate of pain with suggestion of greater risk of osteoarthritis - Quadriceps graft: less harvest site morbidity than BPTB with good functional outcome, some studies suggest higher failure rates

Answer 50

**Autograft Versus Allograft** - autograft, there must be low donor site morbidity; PROs: ease of procurement and the absence of immune response - allograft, there must be low (absent?) potential for disease transmission, PROs: absence of a donor site, quicker surgical time, less postop discomfort (reduce joint stiffness and mm atrophy) - sterilization and radiation have been shown to negatively impact graft tensile strength - All tissues used for autograft or allograft have been shown to be stronger than the native - long-term follow-up has failed to show any statistically significant differences in strength, function, or ligament laxity of allograft compared with autograft reconstructions - most common indication for use of allografts is revision **Xenografts (bovine)** - use generally has been unsuccessful - intensity of the inflammatory reaction caused by the immune response

Answer 51

BPTB - 90% to 95% success rate for stability, but 70% success for return of function to preinjury - advantage = strength of the construct due to the bone-ligament interface. - By securing (interference screws) the bone ends into bone tunnels rather than soft tissue, immediate stability is obtained - bone healing occurs rapidly, in approx 6 to 8 weeks > quicker than healing of soft tissue - higher proportion of patients with anterior knee pain when full function is resumed Hamstring - double semitendinosus/gracilis tendon graft, or quad graft -Fixation within the bone tunnel shortens the graft and with more secure fixation (interference screw), eliminates the previous problem of graft loosening - slower healing incorporation (soft tissue to bone) - Long-term results comparable to BPTB Canine - patellar ligament and/or fascia lata - no clinical reports describe the use of a bone-ligament-bone graft in the dog - proposed as the optimal tissue in the dog > have the greatest strength (comparable to the native cranial cruciate ligament - experimental tensile testing: maximal load less than one-third of the strength of intact CCL - may be the attachment/fixation problem of the graft. In the dog, preferred points of graft insertion have not been studied - historically, femoral tunnel technique has a high failure rate compared with the over-the-top position in dogs - similar problem for tibial anchorage point > graft left attached to the tibial tuberosity shown to be less variable in centre of rotation studies - with the over-the-top fixation there is an overall greater length to the graft, where the most proximal attachment is dependent on the soft tissue (fascia) extension proximal to the patella > proposed to be the weak link - alternative: using the lateral fascia lata, and patellar ligament from the apex of the patella> rerouted under the cranial intermeniscal ligament to the over-the-top position (“under-and-over” technique) - Based on literature, no consensus regarding the “best” CCL replacement position

Answer 52

3 types: **permanent replacements (prostheses)** - resume the function of the native ligament without the possibility of ingrowth - prone to mechanical failure (creep and fatigue) over the long term - Gore-Tex (polytetrafluoroethylene [PTFE]), and Dacron (polyethylene terephthalate) - removed from human market due to high failure rates (30-60%) and wear debris (PTFE particles) that caused a synovial reaction **augmentation devices** - protect the biologic graft during early periods when it is the weakest - may cause stress shielding, resulting in poor graft remodeling/ligamentization - LARS ligaments (Ligament Advanced Reinforcement System) polyethylene terephthalate, and their structure allows tissue ingrowth in the intra-articular part **scaffolds** - designed to allow/promote tissue ingrowth (porous structure) - resorbed with time to allow load transfer to new tissue to optimize remodeling process - bioengineering > the scaffold concept, support cell and tissue ingrowth, leading to production of a neoligament. Progenitor ligament cells are cultured on a matrix scaffold - scaffold then gradually breaks down > progressive mechanical loading of the structure - silk fiber matrix

Answer 53

- basic principle is to place the device in such a manner as to replicate the attachments of the native ligament - native ligament is composed of millions of fibers + not attached at a single discrete point but, rather, diffusely over a much wider area - complex geometry is difficult to replicate - isometric points such that no change in the length of this structure occurs within the joint throughout the stifle ROM > malposition results in fatigue - ideal points of femoral and tibial attachment remains to be defined > bone secured with interference screw into tunnels is 'gold standard' - In the dog, the preferential position for femoral graft placement remains the over-the-top position

Answer 54

- A patellar ligament or fascial strip that remains attached to the tibial tuberosity must first be passed intra-articularly and then over the top of the femoral condyle. - stifle joint extension may impinge upon, and thus compromise, the graft - with osteoarthritis, the intercondylar notch is narrowed by osteophytes > widen the intercondylar notch (“notchplasty”) - vertical incision is made in the tendon of origin of the gastrocnemius muscle proximal to the lateral fabella - ascial graft, it first can be passed under the cranial intermeniscal ligament (“under-and-over” technique) - pretension the graft to eliminate any laxity, joint in extension (assess for draw) - secure the graft proximally is to tie the suture around a screw placed within the distolateral femoral diaphysis - graft length is recommended to be approximately 1.5 times the patella-tibial tuberosity distance - patellar ligament graft can be harvested (autograft or allograft) with a segment of bone - tibial attachment > approximating the craniomedial band attachment may be the preferred position, bone tunnel through to tibial crest - the suture is secured to the femur with a screw and washer and then tensioned appropriately and secured in the tibial bone tunnel with an interference screw - soft-padded bandage or cast for 2 weeks or up to 4 weeks

Answer 55

- approximately 90% good to excellent results - Intraoperative complications revolve primarily around procurement of the autograft - Errors, or difficulty in obtaining the appropriate wedge of the patella > predispose to OA - Fracture of the patella - insufficient size of the patellar wedge > eary graft failure (weakness at the patellar ligament/bone interface) - inadequate width of fascia lata - inAdequate stability/anchorage of the graft - persistence of some degree of craniocaudal joint laxity - graft lengthening during the remodeling process > often, this is the result of soft tissue-to-bone fixation methods - movement of the graft in line with the bone tunnel “bungee effect”

Answer 56

- It has been suggested that the ultimate joint stability that resulted in these cases was due to periarticular fibrosis rather than to the presence of the intra-articular graft. - severe laxity develop are probably caused by loss of integrity of the intra-articular graft - STUDY: extra-cap vs TPLO vs intra-articular patellar ligament graft, the patellar ligament graft was inferior as determined by force plate analysis *loss of confidence in this technique has more to do with the lack of postoperative compliance in our patients compared with a carefully controlled postoperative rehabilitation regimen in human*

Answer 57

- leveling the tibial plateau angle by removing a cranially based wedge of bone from the proximal tibia - biomechanical rationale is similar to TPLO > magnitude of thrust during weight bearing in CCL–deficient stifle joint is dependent on slope of the tibial plateau. - reducing TPA, CCWO mitigates the cranially directed femorotibial shear force - results from static limb models do not account for all muscular forces > Additional in vivo kinematic studies are necessary to validate this technique - difficulty associated with attaining the target tibial plateau angle may be attributed to variability in size and position of the ostectomy and tibial long axis shift - A retrospective analysis: more proximal osteotomy and aligned cranial cortices were more likely to have a postoperative tibial plateau angle near 6 degrees. - **Apelt et al**: cadaveric study validated wedge corresponding to TPA +5 or +7.5 degrees, at the distal extent of the tibial crest result in a stable stifle joint and achieved a postoperative TPA of approximately 6 degrees (caution, as cranial cortices were not aligned in study) - individual assessment > target tibial plateau angle of 4 to 6 degrees - large wedge can shorten the tibia and alter the femoropatellar joint, lowering the patella relative to the femur and leading to hyperextension of the stifle joint - Kinematic gait analysis shown an increase in extension during the swing phase of the stifle and tarsocrural joints > significance of these gait alterations is unknown - steep tibial plateau angles (i.e deformities) would assume a more anatomically correct alignment after cranial tibial closing wedge osteotomy

Answer 58

- Slocum 1984 – initial osteotomy perpendicular to long axis of the tibia - Oxley 2013 – isosceles triangle - Frederick 2017 – perpendicular osteotomy and cranial juxtaarticular wedge for eTPA (technique described by Wallace 2011) - Christ 2018 – proximal osteotomy parallel to TPA, distal osteotomy created to make prox osteotomy equal to width of tibia

Answer 59

– assessed effect of different techniques for CCWO on TPA and tibial morphology - TLA shift and tibial shortening varied with CCWO technique - Frederick 2017 → highest TLA shift - Oxley 2013 → highest tibial shortening and wedge base size - Slocum 1984 – required the most craniocaudal translation to align cranial cortex - generated calculations for wedge angle for each technique that accurately predicted post- TPA 4-6°

Answer 60

large wedge can: - shorten the tibia - alter the femoropatellar joint - lower the patella relative to the femur - lead to hyperextension of the stifle - periarticular soft tissue may not have enough compliance to accommodate such a significant change - tilts the distal portion of the tibial shaft in relation to the proximal portion > result in cranial tibial long axis shift alternative: - smaller wedge + extracapsular stabilization - combination of TPLO + CCWO

Answer 61

Pro's - not requiring specialized equipment as for radial osteotomy - address tibial angular deformity without loss of bone apposition - distal displacement of the patellar ligament attachment > used to treat patella alta - performed in dogs with open tibial growth plates CONS - variability in postop TPA, - patella baja, - limb shortening - craniocaudal angulation of the tibia. -17 dogs, Slocum and Devine: return to function and clinical union by 6 weeks, 9 dogs at 12 months subjectively normal. The dogs also underwent muscle advancement (confounding assessment) - retrospective 91 dogs, 86% good to excellent according to owner and physical exam - small-breed dogs with proximal tibial deformities: good to excellent - TPLO vs CCWO: similar outcomes, not return back to pre-injury in either group, complications CCWO more likely to require revision.

Answer 62

- second-surgery rate for CCWO was 11.9% -nearly twice TPLO (4.5%) + 9 catastrophic tibial fractures - no difference in major complication rates or reoperation rates: (TPLO 7.2% and 6.1%, CCWO 9.5% and 5.4%) - failure of fixation - nonunion

Answer 63

- standard joint exploration and meniscal evaluation via arthroscopy or arthrotomy - medial approach to the proximal tibia - +/- TPLO jig - osteotomy should be as proximal as possible - caudolateral muscle envelope is elevated and protected to reduce bleeding - proximal osteotomy is initially performed using an oscillating saw through the medial, caudal, and cranial cortices - distal osteotomy is marked using a wedge template - A trigonometric method can be used - ensure that the osteotomy lines (from medial to lateral) are parallel to the transverse plane of the joint and coplanar to each other, unless a biplanar wedge is being performed to correct an angular deformity. - Reduction of the cranial tibial closing wedge osteotomy is accomplished by applying a compressive force to the ostectomy gap - Precise correction of the tibial plateau angle will be accomplished only with precise apposition of the ostectomy site

Answer 64

Concerns have been raised about the predictability of achieving appropriate tibial plateau angles (TPA), the occurrence of axis shift and tibial length reduction following cranial closing wedge ostectomy (CCWO). The primary objective of this review was to quantify typical errors in achieving target TPA with CCWO, with secondary objectives of assessing axis shift and length reduction. Retrospective or prospective studies of CCWO. Extracted data from 11 included studies were tabulated and underwent meta-analysis using R. Mean errors in TPA after CCWO ranged from -0.6° to 2.9°, indicating the possibility of both under- and over-correction depending on the selected technique. Errors were relatively consistent for technique subgroups. Mean axis shifts ranged from 3.4° to 5.2°, and length reduction ranged from 0.4% to 3.2% of initial length, based on 6/11 and 3/11 studies, respectively. Data had high heterogeneity, many studies had small populations, and reporting standards were inconsistent. Concerns about the predictability of postoperative TPA may be overstated. With the limited data available, limb shortening does not appear to be a clinically important consideration. **Axis shift will occur to varying degrees and must be considered during CCWO planning, as it influences the postoperative TPA**. Careful choice of CCWO technique may allow clinicians to reliably achieve predictable TPA values.

Answer 65

- intended to neutralize cranial tibial thrust. - procedure has proved to be very effective at neutralizing cranial tibial subluxation in the cranial cruciate–deficient stifle joint - procedure **does not prevent internal tibial rotation or hyperextension** - TPLO does not create normal kinematics of the stifle joint (no surgery to date does) To ensure accurate outcome: - basic concepts of osteotomy, including meticulous preoperative planning, accurate execution of the procedure, robust fixation, and early return to function Warzee study suggests that, during stance phase, tibial plateau leveling transforms cranial tibial thrust into caudal tibial thrust, thereby stabilizing the stifle in the cranio-caudal plane via the constraint of the CaCL. The increase in CaCL stress, which results from tibial plateau rotation, could predispose the CaCL to fatigue failure and therefore would caution against tibial plateau over-rotation

Answer 66

- cadaver models (**warzee 2001**): tibial plateau segment rotation resulting in TPA ~ 6.5 degrees neutralizes cranial tibial subluxation - leveling to less induces caudal tibial subluxation and increases strain on the caudal cruciate ligament - caudal cruciate ligament: undergo degeneration in dogs with experimentally induced CCLR; thus, excessive rotation may result in further degenerated caudal cruciate ligament

Answer 67

Analysis of contact mechanics of the stifle joint revealed that the femoral contact area on the tibial plateau at the stance phase is located more caudal than normal following tibial plateau leveling osteotomy

Answer 68

mediolateral rad (sagittal plane) - measure the tibial plateau angle, - determine saw blade size, - identify osteotomy location, - quantify the magnitude TP rotation, - confirm rotation is within safe, acceptable limits - stifle and tarsocrural joints are flexed to a 90-degree angle - ideal rad: femoral condyles and tibial condyles are perfectly superimposed - centering the radiographic beam on the stifle joint minimizes radiographic projection artifact (measured tibial plateau angle closer to the anatomically measured) - - cranial and caudal extents of the medial tibial condyle determines the tibial plateau axis (prox. orientation line) - intercondylar tubercles of the tibia and the center of rotation of the talus determines the tibial long axis (mechanical axis) caudocranial rad (frontal plane) - screen for the presence of angular or rotational deformities - identify the location of the fibular head with respect to the joint surface - Quantification of tibial alignment in the frontal plane is facilitated by using the proximal and distal tibial joint orientation lines - The mechanical axis of the tibia: midpoint between the intercondylar tubercles of the tibia to the center of the distal intermediate ridge of the tibia. The mechanical medial proximal tibial angle (mMPTA) and the mechanical medial distal tibial angle (mMDTA) can be measured tibial plateau angle - measured at the intersection of the tibial plateau axis and the tibial long axis lines with reference to a line perpendicular to the tibial long axis - tibial plateau axis perpendicular to the tibial long axis would be assigned a tibial plateau angle of zero - magnitude of rotation of the tibial plateau determined from chart designed to achieve a 5-degree postop - plateau segment provides buttress support for the tibial tuberosity > it can be safely rotated to a point that is even with the patellar ligament attachment on the tibial tuberosity (consdier CCWO + TPLO if lower)

Answer 69

- mMPTA = 93.30 ± 1.78 degrees - mMDTA = 95.99 ± 2.70 degrees

Answer 70

- historically: medial edge of the calcaneus should bisect the distal intermediate ridge of the tibia in tru straight CC rad > method has been shown to be susceptible to radiographic positioning artifact - Clinical examination is useful - **computed tomographic** ideal method for accurate quantification of tibial torsion

Answer 71

- Intraobserver variability of ±3.4 degrees - interobserver variability of ±4.8 degrees of tibial plateau angle - significant difference between inexperienced and experienced observers was noted - degenerative changes on the caudal aspect of the tibial plateau were found to obscure the identification of the caudal aspect of the articular surface of the medial tibial condyle

Answer 72

- ideal position would allow accurate leveling with no further anatomic alterations - radial osteotomy > the center dictates the center of rotation of the tibial plateau segment - five positions with respect to the proximal tibial long axis point (the point dividing the intercondylar tubercles) can be considered, namely cranial, caudal, proximal, distal, and centered - structures of the tibial plateau segment follow an arc determined by the distance from the center of osteotomy to the structure itself, termed the distance of eccentricity (Kowaleski) - tibial plateau and the proximal tibial long axis points are all contained within the proximal segment, so they move in unison - unless the osteotomy is centered on the proximal tibial long axis point, this point will change in position after rotation of the tibial plateau segment, causing a shift of the tibial long axis (mathematically most accurate) - **tibial axis shift affects the achieved postoperative TPA** - rotation should occur around the **intersection of the tibial plateau and the tibial long axis** = approximates the anatomic tibial plateau. - result in slight translation of the intercondylar tubercles > BUT the plateau will be accurately leveled = the goal **biomechanical study** evaluating the effect of osteotomy position - centered osteotomy position more effective than the distal in neutralizing cranial tibial thrust because of the more accurate tibial plateau leveling that is achieved

Answer 73

- The exit angle of the osteotomy with respect to the caudal cortex has been used to describe placement > variations in individual anatomy, this is impractical - select the appropriate saw size such that the articular surface of the tibia is avoided - tibial tuberosity should gradually become wider from proximal to distal - tuberosity width of less than 10 mm is a risk factor for avulsion in a cohort of large-breed dogs - in small-breed dogs or cats, it must be smaller - Preoperative and intraoperative planning has been shown to result in a more centered osteotomy position - Two distances (D1 and D2) are measured from the preoperative plan, using the patellar ligament attachment on the tibial tuberosity as a landmark - a third measurement, D3, from the articular surface to the osteotomy exit at the caudal tibial cortex - planned and the actual osteotomy location was 1.72mm for the D1/D2 technique and 1.79mm for the D1/D2/D3 technique; there was no significant difference between the two techniques

Answer 74

- narrow proximal tibia > osteotomy is moved caudally - low vs high patella insertion - excessive tibial plateau slope or proximal tibial growth deformity - presence of a bone tunnel from a previous surgery (lateral fabellotibial suture) - medium-breed dogs with small tibial size but large body weight

Answer 75

- tibiofibular articulation - proximal tibial jig pin (approx 3-4 mm distal to the caudal tibial plateau joint surface) - center of the osteotomy (centered on the axis' intersection)

Answer 76

- joint surface is identified by probing with a fine (25 gauge) needle progressively from distal to proximal in the middle of the collateral ligament - the long axis of the patellar ligament is essentially perpendicular to the proximal tibial joint surface in most cases in which no tibial deformity is present - use of a tibial plateau leveling osteotomy jig with a saw guide has been shown to result in more accurate placement of the osteotomy and more accurate leveling of the tibial plateau - without a jig shown to result in approx 15 degrees of craniolateral deviation of the osteotomy, fibular fracture, and fixation failure - use of sponges has been shown to be effective in protecting the proximal tibial soft tissue envelope but results in retention of microscopic cotton particulate debris in the operative site - Tibial tuberosity width, saw blade exit angle caudal tibial cortex, center of the osteotomy and adequate size of segment to fit plate - A slight step from lateral to medial > Realignment of the cortices result in angular and rotational deformity - K-wire proximal to Sharpey's fibers > to mitigate the risk of tibial tuberosity fracture - closure of the conjoined tendons of insertion of the sartorius, gracilis, and semitendinosus muscles (pes anserinus) - post-op care

Answer 77

Compared to conventional, locking screws shown to: - maintain tibial plateau positioning better - less change in the tibial plateau angle - improved osteotomy healing

Answer 78

- magnitude of deformity in the frontal plane determined by using CORA (Dismukes et al) - computed tomographic determination of tibial torsion is recommended - Modest corrections in the frontal plane (varus and valgus) can be accomplished by sliding the distal jig arm > Sliding the jig arm medial (away from the tibia) will correct varus and sliding the jig arm lateral (toward the tibia) will correct valgus. - these corrections occur at the expense of apposition of the tibial osteotomy (radial opening wedge osteotomy) - increases stress on the fixation; thus, maintenance of bone contact on the opposite cortex and robust plate fixation

Answer 79

- Few publications report objective measures of gait - experimental study of 6: no significant differences in peak vertical force and vertical impulse in TPLO vs normal @ 18wk - retrospec: significantly smaller thigh circumference and stifle joint range of motion were present in the tibial plateau leveling osteotomy treated limbs - measurable increase in the severity of radiographic changes attributable to osteoarthritis was noted at 8 weeks following surgery - Early physiotherapy was shown to result in significantly greater thigh muscle circumference and stifle joint range of motion at 6 weeks - retrospective longitudinal study: no association between postoperative tibial plateau angle and ground reaction forces, postoperative TPA was 0-14 degrees - 93% of owners were satisfied or very satisfied

Answer 80

2.5 to 25.9% - arthrotomy versus arthroscopy - prolonged anaesthetic, - prolonged surgical - prolonged postop hospitalization

Answer 81

- OA more severe in lateral fabellotibial suture than a tibial plateau leveling osteotomy - two prospective clinical trials TPLO vs LFS: - kinematic and owner satisfaction results indicated that dogs that underwent TPLO had better outcomes - achieved normal limb loading faster for TPLO and function that was indistinguishable from the control population by 1 year

Answer 82

17 dogs, mean 25mths, stable **partial tears** - cranial cruciate ligament appeared similar to the initial surgery (stable intact fibers persisted) - caudal cruciate ligament, menisci, and articular cartilage of the medial and lateral compartments appeared normal in 16 of 17 joints - lower tibial plateau angles were associated with decreased cranial cruciate ligament strain 46 stifles **complete/unstable partial** - MOS G3-4 medial/lateral femoral condyle, progression to complete rupture and meniscal injury in some cases - (altered contact mechanics +/- ongoing instability)

Answer 83

- tibial fracture - intra-articular screw placement, - significant hemorrhage (often related to laceration of the cranial tibial artery), - broken drill bits, - fibular fracture, - intra-articular jig pin placement, - placement of a bone screw into the osteotomy, - retained surgical sponge, - broken holding pin, - broken screw prospective, multicenter study - intraoperative complication rate was 7.1% minimized by: - experience - preoperative planning and surgical execution - Anatomically shaped locking plates > manufacturer predetermines the screw angulation - post-op rads: screws should be removed, redirected, and replaced immediately

Answer 84

- electrosurgical coagulation or application of hemostatic agents or hemostatic clips. - anatomic investigation has confirmed that the source of the hemorrhage is typically the cranial tibial artery or vein - significant hemorrhage, the area caudal to the tibia is initially packed with gauze to control the hemorrhage - severe hemorrhage, temporary occlusion of the femoral, popliteal, or cranial tibial arteries - approach to distal popliteal proximal to cranial tibial branch: between bellies of sartorius then separating between vastus medialis and semimembranosus Cieciora 2022 – rotation of TPLO → compression of cranial tibial artery Roses 2022 – rotation of tibial plateau segment and closure of pes sufficient for hemostasis after cranial tibial artery transection during TPLO

Answer 85

- incisional: tissue swelling, irritation, seroma, - wound dehiscence - incisional infection - hematoma, edema or bruising - self-trauma (suture or staple removal) - tibial fracture - joint capsule swelling - secondary loss of reduction (also known as **rockback**) minimised by: - Meticulous soft tissue handling and careful elevation and preservation of fascia to ensure plate coverage

Answer 86

- patellar ligament thickening, - tibial tuberosity fracture (improved with osteotomy position, width, K- wire placement, limiting rotation to “safe point” and avoiding Bilateral, single-stage) - periosteal reaction, - osteomyelitis, - postliminary meniscal tear, - implant loosening, - screw breakage, - retained surgical sponge, - fibular fracture, - patellar fracture, - septic arthritis, - tibial fracture - luxation of the tendon of the long digital extensor muscle **Bilateral, single-stage** > higher incidence of complications, including an 8.5- to 9.6-fold increased risk for tibial tuberosity fracture - complications 40% of dogs in one study and in 5 of 25 dogs (20%) in another

Answer 87

**Peress 2021** – incidence of complications higher with bilateral single session - complications: major 10.1% vs 3.8%, minor 38.4% vs 15.6% - TT# requiring revision not significantly different

Answer 88

- movement of the tibial plateau segment occurs along the osteotomy site > change in the tibial plateau angle during healing - reported to be 1.5 ± 2.2 degrees (range, ±3 to 9 degrees) - mechanical rather than a biologic process - magnitude of change is small, likely does not alter the theoretical effectiveness of neutralizing thrust. However> implies that minor fixation failure may occur during healing that could be significant if loss of fixation - anatomically contoured locking bone plate study > mean tibial plateau angle change was 0.15 ± 1.32 degrees

Answer 89

- common following TPLO and may cause lameness in the first few months - STUDY: 13 of 31 stifles at 1 month postoperatively, in 9 of 18 stifles at 2 months postoperatively, lower postoperative TPA (<6 degrees) and greater body weight were associated with a higher risk - speculate that increased stress on the patellar ligament following TPLO may play a role - kerf size and position of the osteotomy shown to affect the distance from the patellar ligament attachment on tuberosity to the intercondylar tubercles of the tibia following rotation. - distance represents the lever arm from which the quadriceps mechanism gains mechanical advantage in extending the stifle joint. As this distance is reduced, the force on the patellar ligament during weight bearing may be increased, resulting in patellar ligament strain - A shorter lever arm requires more force to move an object the same distance - Histologic analysis: collagen fiber disorganization, neovascularization with lack of inflammation = supporting a biomechanical basis - Other potential causes include trauma during sx - radiographic grading: grade 0—mild, normal up to double preoperative thickness; grade 1—moderate, 6 to 11 mm in thickness; and grade 2—severe, ≥12 mm - demitis = grade 2 thickening, lameness attributable to the patellar, pain on palpation of the patellar ligament, and soft tissue swelling. Risk factors - cranially positioned osteotomy - partially intact cranial cruciate ligament - postoperative tibial tuberosity fracture

Answer 90

- incidence using a specific cast bone plate estimated ~7x greater than expected - galvanic or crevice corrosion dt being cast stainless steel components rather than wrought > plate did not meet ASTM specifications - a direct association between the specific implant and the development of osseous neoplasia could not be confirmed

Answer 91

- corrosion - specific metal alloy - electrolysis between dissimilar metals of the implant - tissue damage at the time of trauma or surgical repair - altered cellular activity related to delayed union, nonunion, or infection.

Answer 92

- excessive (steep) TPA (angle >34 degrees with 24 mm saw radius or when rotation past the insertion of the patellar ligament - combined with a medial or lateral closing wedge osteotomy to address varus or valgus and/or torsion - TPLO planned first > amount of safe rotation is determined by measuring the distance along the osteotomy that the plateau can be rotated once segment is even with the patellar ligament attachment - CCWO is planned to correct the remaining tibial plateau angle - CCWO positioned such that the apex is placed at the caudal cortical margin of the tibial plateau leveling osteotomy - TPLO cut, segment is rotated and secured with two Kirschner wires, the CCWO is completed, and the ostectomized segment is removed. The tibial segments are reduced and secured with a pin distal to proximal traversing all three bone segments, to provide temporary stabilization until the tension band wires and plate(s) are applied - **varus or valgus with eTPA**> CCWO can be performed as a biplanar wedge, rather than as coplanar - alternative is to insert two jig pins parallel to the proximal and distal tibial articular surface, and cut parallel - cases with **patella alta**, the closing wedge can be used to position the patella more distally (TPLO rotation can be adjusted to compensate)

Answer 93

- modified by Talaat and others to utilize linear osteotomies for CCWO (rather than second radial as per slocum) - TPLO osteotomy is made partially > proximal CCWO is scored on the medial cortex so that it intersects the radial osteotomy - CCWO created using sterile angle template, a sterile goniometer, or a simple geometric method - TPLO completed ad stabilised with 2x kwires - CCWO performed, wedge reduced and cranial cortices aigned and compressed with a wire is placed from craniodistal to caudoproximal - tension band placed, then TPLO plate - wedge can be morselized and placed as autogenous corticocancellous bone graft > cranial closing tibial wedge ostectomy site heals most slowly - lateral translation of the tibial tuberosity segment can be accomplished before the fixation is applied i.e. for medial patellar luxation - fixation of the cranial tibial tuberosity segment must be rigid because the distractive force of the quadriceps mechanism is considerable: wires should be of a suitably large gauge [2.4 mm] Steinmann pins and 18 gauge or 16 gauge orthopedic wire in most patients - Double plate fixation is recommended if tibial size is sufficient to place a second bone plate; in patients weighing 30 to 40 kg

Answer 94

1.TPLO + TTT + trochleoplasty - TPLO performed first - TTT cut started same level as the insertion point of the patellar ligament onto the tibial tuberosity - ensure that the tibial tuberosity segment is of sufficient size and shape to mitigate the possibility of a fracture and allow for application of adequate fixation - fulcrum effect that is created when a TPLO is combined with a TTT - Birks and colleagues found that load to failure for a TTT was higher than with a TPLO and TTT. **Redolfi 2024**: retrospec, 24 stifles, grade III or IV MPL, low mj complication rate (18%): surgical site infection (n = 3) and recurrent grade II MPL (n = 1), long term >1yr 21/22 clinically sound and 23/24 stifles complete resolution of MPL. TT cut is differnt location to leonard **Leonard 2016**: Patellar re-luxation did not occur in any of the 13 stifles available for in-hospital follow-up, short follow up, patella lig thivken 7/13 2.Modified tibial plateau levelling + trochleoplasty - tibia laterally translated by 3 to 6 mm and was externally and abaxially rotated - plate contour: proximal portion forming approximately a 30° angle and medially twisted - six grade 2 and seven grade 3 MPL **Langenbach 2010**: 12 dogs, two cases, one due to failure of fixation and another due to screw breakage, No patella luxated alternatives - TTA- TTT (recession sulcoplasty may affect PTA) - TTO with TTT - TTT with extra-cap - CBLO with TTT (cadeaver study, maintains a buttress effect of the tibial crest against the tibial plateau, load to failure same TTT vs CBLO-TTT) Newman 2014 – TTTA more effective at lateralization of TT vs pin and tension band wire - no significant difference in peak load and energy to failure or stiffness Hackett 2021 – mini-TTTA vs ECS+TTT - no significant difference in clinical outcome at 8w - mini-TTTA → 1/27 reluxation, ECS+TTT → 5/26 major complication (failure/explant)

Answer 95

- restrospective, <15kg using fixin plate - complications: overall 18.4%, reluxation 6.6% vs 8.8% non-translation group - decreased bone apposition at osetotomy sire: The mean healing time of 73 days observed in the treatment group was similar to the healing time observed in our control - a modified TPLO with no difference in complication rates when compared with traditional surgical techniques. Application of this TPLO technique results in a small shift in the mechanical axis of the tibia - no compression achieved bewteen fragments - gap between plate and bone??

Answer 96

**personal surgical preference is a major factor in case selection** 1. late meniscal tears: TTA up to 21% in older report 2. proposed increased stress (TPLO) versus decreased stress (TTA) on the patellar tendon > Theoretically, diminished force can protect the articular cartilage of both the patella and the femur from subsequent damage 3. Femorotibial contact pressure and location: TTA appears to restore the normal femorotibial contact and pressure distributions, whereas TPLO results in a decrease (12%) of contact area and caudal positioning of peak pressure distribution 4. The tibial plateau remains unaltered with TTA, whereas with TPLO, the tibial plateau is effectively placing the joint in 15–20 degree of increased flexion 5. tibiofemoral shear force is dependent upon PTA > altering the direction patellar tendon force obtains dynamic joint stability. either parallel to the patellar tendon (TTA) or to the functional axis of the tibia (TPLO), the difference could account for as much as 10–15 difference in endpoint after surgery > appear that the TPLO overcorrects for the cross-over point compared with TTA 6. TTA correcting the tibiofemoral shear force closer to neutral at full extension during weight bearing, thus there may be less stress placed on the CaCL. reoperation 5-9% TTA 11% TPLO

Answer 97

**Wemmers 2022** – systematic review - general lack of strong evidence - both techniques successful → no lameness long-term in majority of patients - TTA → better OA scores at 6m - TPLO → lower rate of SSI **Knebel 2020** – no statistically significant difference in outcome with TPLO vs MMP - TPLO → more dogs reached ref range pVF at 3m and higher mean pVF and VI at 6m - complications: overall 13.2%, MMP → 3.17x higher risk of revision **Moore 2020** – TPLO (n=133) → less progression of arthritis, less pain and mobility issues vs TTA (n=33) - bilateral stifle sx → more progression of OA - owner-assessed CBPI and COI scores better for TPLO **Livet 2019** – TPLO vs TTA-Rapid → no difference in long term outcome **Ober 2019** – TPLO and TTA → passive stabilisation of the stifle joint, Ex vivo biomechanical study - TTA → increased patella tendon and retinacular fascial tension - TPLO → increased joint capsule and collateral ligament tension - TPLO seems more effective than TTA at restoring craniocaudal stability of the stifle, associated with a degree of translation that did not differ from joints with intact CCL, regardless of the degree of stifle flexion

Answer 98

**Krotscheck 2016** – TPLO achieved operated limb function similar to control at 6-12 m - TTA and ECS did not achieve normal GRF at trot - SI for TTA at walk and for TPLO at walk and trot not different to control - TTA - 57% maintained some form of instability with tibial compression - less lameness in early post-op period **Christopher 2013** – compared TPLO, TTA and TightRope - major complications: TTA → higher complication rate and subsequent meniscal tear - TTA 38.9%, TPLO 18.5%, TR 8.9% - subsequent meniscal tear most common: TTA 3x more likely than TPLO, 6x TR - %function: TTA 89.2±11%, TPLO 93.1±10%, TR 92.7±19.3% - TPLO and TR significantly more likely to reach full function - number of TTA small (32) vs 152 TPLO and 144 TR - no treatments completely eliminated pain (75% reach full function)

Answer 99

**Oxley 2012** – no significant difference in lameness score, complication or revision rates for TPLO vs modified CCWO - isosceles triangle → more proximal osteotomy, better alignment of cranial and caudal cortices → less tibial long axis shift → more predictable post-op TPA - median post-op TPA: TPLO 5.5°, mCCWO 6.5° - not significantly different - complications: major complication rate: TPLO 7.2%, revision rate 6.1% mCCWO 9.5%, revision rate 5.4% - outcomes: good in 90-97%, no significant difference between groups Corr 2007 – no significant difference in outcome for TPLO vs CCWO - all dogs → rapid return to weight bearing with no pain on palpation, reduced lameness and good ROM - complications not significantly different but CCWO → more major complications

Answer 100

- sudden internal rotation of the tibia with lateralization of the hock, and a sudden lateral change in direction of the stifle joint during weight bearing - reason for its occurrence is also unknown, but is thought to be a result of insufficient correction of tibial torsion or angular deformity - 3.1% pivot shift after TPLO - medial meniscectomy → risk factor for pivot shift Dx - tibial pivot compression test (lampart 2023) - External rotation and valgus stress are applied.

Answer 101

- neutralizing cranial tibial thrust is achieved by advancing the patellar ligament (via TT ostectomy) perpendicular to the common tangent of the femoral and tibial contact points - based on a mechanical model analysis of the human knee by Nisell et al.,317 who described a resultant joint force approximately parallel to the patellar ligament - purpose of TTA is to move the tibial tuberosity sufficiently far cranially to maintain a patellar tendon angle of 90 degrees or less from the point of first foot-strike (maximal stifle joint extension during weight bearing) so as to obtain a neutrally or caudally directed tibiofemoral shear force during ambulation - validated in multiple ex vivo experimental studies

Answer 102

- mediolateral radiographic projection is centered on the joint close to full extension (approximately 135 degrees) - recommended that the patellar tendon angle should be determined by using the common tangent between the tibial and femoral surfaces at their contact point - Less variation has been reported using the contact point compared with PTA - contact point is determined by drawing circles of the femoral condyles and the tibial plateau; this line measure the amount of advancement required to achieve a 90-degree angle with the patellar ligament - Errors will occur because of anatomic variability (tibial drawer or stifle joint extension angle), patellar ligament insertion point (high vs. low), variation between measurement methods

Answer 103

- aponeurosis incision is made a few millimeters caudal and parallel to the tibial crest + periosteum of the tibial crest is reflected cranially - eight-hole drill guide (Kyon) is positioned parrallel to crest, first hole aligned at patellar ligament attachment and predrilled - cranial tibial margin should intersect approximately at the level of the screw hole in this distal portion of the plate (after advancement plate holes will be central tibia) - osteotomy, from a point immediately cranial to the medial meniscus (and cranial to the tendon of origin of the long digital extensor muscle) - partial osteotomy performed first - advancement plate (Kyon) is contoured - A fork designed to fit within the tension-band plate is secured into the tibial crest by impaction - crest with attached plate is moved cranially by using a spacer attached to a T-handle that corresponds to the selected cage width - “ears” of the cage (screw holes) are contoured: an upward bend caudally, and a downward bend cranially. - cage placed approximately 2 to 3 mm from the proximal tibial bone margin - entire tibial crest is allowed to shift a few millimeters proximally to ensure that the patella position remains unaltered (arc of rotation remains centered at the patella) - bone graft ?? auto or allograft - apposition of the aponeurosis of the medial thigh muscles to the periosteum of the tibial crest to cover the implants - rads and bandage post-op

Answer 104

- eliminated the plate, instead relying only on the cage to provide the advancement and stability. Modified techniques: - Modified Maquet Procedure - TTA Rapid - TTA-2 - forkless TTA (Matchwick 2021) - biomaterial wedge for MMP (terreros 2021)

Answer 105

1600 cases - 2.3% to 26.1% major complications - 7.6% to 37% minor complications - reoperation rate 9.8% - many complications attributed to technical failures with the surgical technique > insufficient advancement and improper osteotomy placement - Long-term follow-up limited to an average of 8 to 9 months postoperatively > good to excellent outcome >90% reported by owners - Radiographic healing was reported to occur by 8 to 10 weeks meniscal tears - whether result of a postliminary tear of an intact meniscus or simply a latent tear - meniscal release recommended? - newer studies report lower meniscal tear rate Persistent instability in the joint after tibial tuberosity advancement has been suggested by some surgeons> under-advancement Serratore 2018 – explant of TTA cage to manage SSI → 40% complications (3/8 TT fracture) modified tibial tuberosity advancement procedures > there have been few published investigations, new compliucations is tibial fracture

Answer 106

1. Osteotomy fragment too small 2. Osteotomy cut too low (i.e., at the same level of the distal screw insertions > stress riser leading to a tibial fracture; osteotomy should begin at least 1 cm proximal to the proximal screw). 3. Not allowing the proximal shift of the tuberosity with advancement (resulting in distal displacement of the patella). 4. Malalignment of the tuberosity, predisposing to a patellar luxation (angled osteotomy or improperly contoured plate) 5. forks are too far away from the leading edge of the bone (resulting in poor purchase in this area of thinner bone) 6. Plate distal end lies caudal to the tibial shaft (this part of the plate can be bent to compensate) 7. No advanced enough - 12mm advancement → normalisation of stifle kinematics at 135° and 145° extension - 9mm advancement failed to normalise kinematics

Answer 107

- postliminary meniscal tears 3.2%-21% - tibial tuberosity fractures (with or without implant failure), - infection SSI 7% - medial patella luxation, - fracture of the tibia (20% MMP @ marquet hole) - cage malposition - intra-articular screw - delayed union or nonunion of the gap - progression of OA 55% technical sugical cimplications have improved over time > appear to be the case with the more recent clinical reports, types of failures remain essentially unchanged **Serratore 2018** – explant of TTA cage to manage SSI → 40% complications (3/8 TT fracture)

Answer 108

proximal patellar ligament attachment - larger tibial tuberosity/crest - larger plate can be applied to the tibial crest. - The cage is buttressed with adequate bone> theoretically will disperse all the forces applied to the tibial crest. distal patellar ligament attachment - smaller tibial tuberosity/crest, - smaller plate is applied to the tibial crest. - cage located proximal to the most proximal position of the plate, and little bone is present for support. - risk of fracture may be greater as the result of lesser buttress support

Answer 109

- may be a contraindication - Anecdotally, the proposed cut-off point is 30 degrees (No data have been published) - larger TPA sually means larger advamcment required. currently, this advancement distance is limited to 15 mm (largest cage size available). - high tibial plateau angle also places the stifle joint in a relative position of hyperextension - gross stifle joint angle is limited, and the leg cannot be fully extended. Despite achieving patellar tendon angle of 90 degrees, the joint remains in the hyperextended position - case by case selection > aim to lower the TPA to reduce tibiofemoral shear force + correct the tibial conformation to place the stifle joint in the appropriate position - Correction of the angular deformity must not be ignored > some cases may not be suitable for TTA

Answer 110

osteotomy for tibial tuberosity advancement is performed in the frontal plane, it cannot simultaneously address deformities of tibial varus, valgus, or torsion, all of which require some form of transverse osteotomy. - a second transverse osteotomy is required - TTA not recommended

Answer 111

- tibial tuberosity advancement can be performed simultaneously - plate is slightly overbent to conform - the cranial cage ear may be elevated off of the bone [tuberosity] by placing one or two small metal washers under this ear - No additional fixation is usually required (pins and 8 wire )

Answer 112

- No limitations on patient size 10.4 kg and as large as 83 kg - mitations dependent on the availability of appropriately sized implants (two- to eight-hole plates and 3 mm to 15 mm cage widths

Answer 113

- Prospective study and case series. Animals: Dogs treated with TTA (n= 67). - no difference in healing between groups at 6.8 weeks and 4.2 months - osteotomy gap created during TTA healed within expected time regardless of bone graft use - likely that the metaphyseal location of the osteotomy with its rich blood supply and abundant cancellous bone + blood clot + imediate stabilisation - We found complete healing at a mean time of 14.56 week (11 weeks otherwise reported)

Answer 114

- similar to TTA = reduce the patellar tendon angle to 90 degrees at weight-bearing angle - Three cuts in the proximal tibia create a partial wedge ostectomy caudal to a partial tibial crest osteotomy - The tibial plateau is made perpendicular to the patellar ligament by rotating the proximal tibial fragment to close the wedge ostectomy and simultaneously advancing the tibial tuberosity. - biomechanical investigations evaluating the effectiveness of TTO in neutralizing the cranial tibial thrust force are limited (only one Jensen 2020)

Answer 115

- minimal change to the orientation of the tibiofemoral articulating surfaces - Advancing the tibial tuberosity reduces retropatellar forces > may lessen post-operative chondromalacia and OA - relatively small osteotomy gap caudal to the tibial tuberosity - no loss of limb length - proposed low technical difficulty when the appropriate instrumentation Potential disadvantages - variability of the postoperative patellar tendon-to-tibial plateau angle when the recommended calculations - additional fixation with intraoperative fractures of partial osteotomies.

Answer 116

**Jensen 2020** – TTO restored stability up to 125° joint angle **de la Puerta 2019** – tibial tuberosity fracture after TTO 25/113 (22%) - associated with reduced cortical hinge width **Livet 2019** – modified TTO for correction of concurrent CCLR, tibial deformities or patellar lux - appropriate PTA and mMPTA correction - outcome: 77.8% no lameness **Bruce 2007** – 89.1% positive tibial compression test at 6-12 week f/u, 94% judged as normal/near normal by owners Post of TPAs all greater that 5-6 degrees, thus tibial thrust in **not** elimated Variation in the position of the tibial tuberosity affected the planning > specific tibial morphology makes some cases better candidates for a tibial plateau leveling procedure and others may require a procedure that reduces the patellar tendon angle

Answer 117

- overall: 36.0% (bruce 2007) - intra-op 23.4% distal tibial tuberosity fracture - post-op: 10.9% - tibial crest fracture with (n = 9) - fibular fracture (n = 4), - patellar tendinitis (n = 3), - postliminary meniscal injury (n = 3), - implant failure (n = 3), - patellar fracture (n = 2), - abscess (n = 1).

Answer 118

The wedge angle (WA) can be calculated according to Renwick et al (modification of Bruce et al) **WA = 0.6 X CA + 7.3** CA is the angle of correction of the patellar tendon angle needed to achieve 90 degrees. - If TPA - WA is less than 0 degrees, instead WA calculated as TPA – 5 degrees - if preop patellar tendon angle close to 90 degrees, instead WA calculated as TPA – 12 degrees - transverse 2.0 mm hole is drilled caudal to the cranial cortex at a distance equal to the length of the patellar ligament distal to the patellar ligament attachment - crest osteotomy performed > wedge of precalculated size is marked at midpoint - The apex of this wedge is a predrilled 2 mm hole cranial to the caudal cortex - wedge closed and stabilsied with plate - if crest fractures at distal attachment > pin and tension band is applied - Cancellous bone graft

Answer 119

Bula 2021 – TTTA for CrCLR + MPL in cats; n=3 cats, 4 stifles - osseous union and clinical improvement in all cases - 1 major complication – tibial fracture requiring revision Bilmont 2018 – TPLO did not stabilise CrCL deficient feline stifle - TPLO with TPA +5° → no significant effect on cranial tibial subluxation or tibial rotation angle in cats - additional rotation → no significant effect Retournard 2016 – ex vivo model: TTA did not stabilize CrCL-deficient feline stifle Mindner 2016 – TPLO in 11 cats → no-mild intermittent lameness in all cats - no major complications Perry 2010 – TTA in 2 cats → long-term resolution of lameness Harasen 2005 – n=17 cats with cruciate rupture (either isolated or multi-ligamentous) - multi-ligamentous treated with primary repair +/- augmentation - isolated → ECS Scavelli 1987 – non-surgical treatment for CrCL rupture in cats → 16/18 satisfactory outcome - clinically normal gait with minimal muscle atrophy - 80% had residual cranial drawer and DJD

Answer 120

Sanders 2024 – pre-closure antiseptic lavage did not reduce incidence of SSI after TPLO - overall SSI 11.04% - risk factors: bilateral single session 2.5x, bWt – 5kg increase →11% increase risk - post-operative antimicrobials protective Clark 2020 – overall infection: 79/308 (25.6%) - post-operative antibiotics not protective - bWt correlated with deep SSI and resistant infection - prolonged sx and ga time correlated with superficial and deep SSI and resistance Cox 2020 – LFS → SSI rate 17.3%, explantation in 53% of SSI cases - risk factors: increasing bodyweight, use of propofol - infection correlated with more severe lameness at 6w - antibiotic therapy had to association Garcia 2020 – subclinical bacteriuria did not predispose to SSI Hagen 2020 – post-op antimicrobials more protective if given >60 prior to incision vs within 30 and 60m - overall 11% SSI, MRSP 28%

Answer 121

- CORA-based leveling osteotomy: correction of anatomic axis CORA (procurvatum of tibia) - The normal canine tibia has a proximal curvature (procurvatum)and therefore, has a CORA. - proximal anatomic longitudinal axis is not aligned with the distal anatomic longitudinal axis. When the proximal and distal anatomic lines are drawn, the intersection of the anatomic proximal and distal axis lines defines the position of the CORA - CORA angle = angle of correction to achieve desired TPA → post-operative TPA 9-12° - post-TPA 9-12° to maintain compliance of cranial soft tissues → potentially reduce cartilage wear and joint degeneration - neutralization of the quadriceps disruptive moment was achieved with a screw - moves the tibial crest cranially TPLO suggested to have significant joint mechanical alteration which may be contributory to articular cartilage lesions. - abnormal joint mechanics because osteotomy is not based on the mechanical or anatomic CORA. - Axis of Correction (ACA) is not aligned with the CORA resulting in mal-alignment and secondary translation. - result is caudal displacement of the weight bearing axis and a focal increase in joint force. (TPLO creates a caudal thrust) - **Hulse et al**: CBLO proposes to maintain normal stress distribution and kinematics of stifle and achiev 90 degress PTA - also eliminate cuadal thrust and therefore cranial cartilage lesions - the PTA curve following CBLO is consistent with placement of the joint into relative flexion by rotation of the proximal metaphysis during surgery.

Answer 122

- one proposed advantage = avoidance of growth plate - recurvatum induced by overcorrection in 1 dog - valgus deformity in 2/15 due to plate screw engaging distolateral aspect of prox physis

Answer 123

- 77% full function, 19% acceptable function, 4% unacceptable function - second-look arthroscopy after CBLO → minimal-no articular cartilage change (MOS 0-1 pre-op to MOS 0-2) - compression screw → closure of tibial tuberosity apophysis → no apparent clinical effect Raske et al: Overall change in TPA for the dogs we report was not significantly different between postoperative and recheck radiographs. With the exception of 2 dogs, change in TPA was <2°. CBLO using a bone plate augmented with a HCS appears to effectively maintain the TPA

Answer 124

- 11.4% major (6/70 post-liminary meniscal injury, 2 implant-related) - 2/31 screw complications - hulse et al: case series TPA shift occurred in (18%) cases; of these, 4 required surgical revision.

Answer 125

in vivo by fluoroscopic evaluation of walking dogs post-TPLO, which demonstrated reduced CTT, although caudal translation was observed in 10/16 dogs and persistent CTT in 5/16, despite all post-TPLO TPA values lying within a typically accepted range Both quadriceps contraction and gastrocnemius contraction can generate cranial tibial translation,18, 19 whereas the flexors of the stifle joint (hamstring muscles) actively oppose this movement.

Answer 126

- Ex vivo experimental study. 7 legs - effectiveness of CBLO in stabilizing the cruciate-deficient stifle - hamstring load improved stifle stability, especially after medial meniscal release - CBLO to 10° mostly eliminated cranial tibial thrust - joint angle (TPA), integrity of meniscus and hamstring activation all contribute to stifle stability - compression screw → closure of tibial tuberosity apophysis → no apparent clinical effect

Answer 127

**Worden 2023** – virtual surgical correction for eTPA - mCCWO → moderate alteration to tibial geometry - TPLO+CCWO → least alteration to tibial morphology but most unstable construct - coplanar CBLO → most alteration to tibial morphology **Schlag 2020** – CBLO with coplanar CCWO for eTPA - mean TPA 43° reduced to 10° post-op and 10° final (no TPA shift) - complications: pin migration (3.6%), screw breakage (3.6%), late onset caudolateral band tear (3.6%), late-onset meniscal tear (7.2%), SSI (3.6%) - outcome: 18/21 (85.7%) full function, 3/21 (14.3%) acceptable

Answer 128

ther TPA measurement methods focusing on tibial plateau slope determination usingdifferent types of proximal tibial axes have also been described in the literature [12-14]. However, regardless of the method used, radiographic evaluation of TPA is stillvery subjective [9]. It was confirmed that TPA measurements can be misinterpreted incases of poor limb positioning when the x-ray beam is not centered on the stifle jointduring radiographic imaging [15]. Also, severe osteophyte formations around tibialcondyles can hinder the identi fication of the cranial and caudal margins of the tibialplateau [10].

Answer 129

- primary stabilizer against caudal tibial subluxation (caudal drawer) - functions with the cranial cruciate ligament to limit internal rotation and hyperextension - Isolated injury of the caudal is rare; therefore, treatment and outcome are speculative - usually combined with rupture of the MCL and/or CCL - cause of injury usually trauma - direct blow to the cranioproximal region of the tibia, causing a caudal drawer motion overloading the ligament, leads to rupture - If the stifle joint is in extension during the injury, a collateral ligament injury may occur - damage to CaCL common with CrCL > 21 of 24 dogs had some degree of caudal cruciate ligament damage - rare cases, a negative TPA may predispose to caudal cruciate ligament rupture

Answer 130

- vary in severity from mild weight-bearing lameness to non–weight-bearing - differentiation of caudal drawer motion from cranial drawer motion is difficult > 7 of 14 dogs were misdiagnosed as having a cranial cruciate - Rupture of the caudal cruciate ligament results in caudal subluxation and reduced prominence of the tibial tuberosity (tibial sag) - distinguishing cranial from caudal drawer > in CaCL, the thumb placed behind the fibular head travels from caudal to the thumb behind the fabella to a position approximately even with it. - draw > abrupt stop as CrCL becomes taut = sharp and distinct endpoint. CrCLR is less distinct. - Radiographs: fractures, avulsion fragments, and OA

Answer 131

- long-term follow-up is lacking > appropriate treatment are speculative - various stabilization techniques (avulsion fractures with screws, removal of the ligament, extracapsular techniques or intra-articular tissue grafts or osteotomies) appear to be similar according to short-term follow-up data - experimental study: at 6 months, none of the dogs was subjectively lame, Necropsy findings did not reveal articular cartilage defects - lameness in clinical cases may persist much longer than that following experimental - medical treatment for 3 to 6 weeks may be justified, especially in cats or small dogs - In large-breed, active dogs, joint exploration followed by stabilization recommended

Answer 132

- Avulsion of the femoral attachment appears to be more common - fixation with bone screw or a wire suture formed from a loop of cerclage wire placed through bone tunnels or divergent Kirschner wires

Answer 133

- remnants of the caudal cruciate ligament are debrided, and the joint is explore medial side - caudomedial joint capsule can be imbricated with mattress 3/0–0 sutures - large 0–4 braided polyester, or nylon leader line suture can be placed from just distal to the apex of the patella to a drill hole in the caudomedial tibia lateral side - large suture from the proximolateral edge of the patellar ligament just distal to the apex of the patella to a drill hole in the fibular head - caudolateral joint capsule can be imbricated with mattress sutures desmodesis of the medial collateral ligament or tenodesis of the long digital extensor tendon or popliteal tendon can be employed - Exercise restriction is recommended for 6 weeks - outcomes following extracapsular stabilization of avulsion fragments are very good, despite the stability achieved

Answer 134

- aetiopathogenesis of CCLD in cats is unclear and epidemiological studies are lacking - Both conservative and different surgical treatments have been deemed successful - Extracapsular stabilisation with lateral suture is commonly used - osteotomy procedures have been described. - 14% developed bilateral CCLD - 47% had meniscal injuries - Postoperative surgical complications in 27% **Boge 2020** - long-term outcome of surgically and conservatively treated cats, lateral fabellotibial suture (LFS) technique was used in all cats substantial proportion of the cats had a FMPI score indicative of chronic pain, higher proportion of the surgically than the conservatively treated cats had an FMPI score >3 selection bias due to a clinical decision to treat less lame cats with less severe joint disease conservatively Multi-ligament stifle injuries, meniscal disease and postoperative complications were frequently observed in surgically treated cats **Bilmont 2018** – TPLO did not stabilise CrCL deficient feline stifle - TPLO with TPA +5° → no significant effect on cranial tibial subluxation or tibial rotation angle in cats - additional rotation → no significant effect **Retournard 2016** – ex vivo model: TTA did not stabilize CrCL-deficient feline stifle **Mindner 2016** – TPLO in 11 cats → no-mild intermittent lameness in all cats - no major complications

Answer 135

37 of 117 (31%) and 24 of 101 (24%) dogs in this study were administered analgesics at 6-month and long-term follow-up, respectively. evidence to support that > 30% chronic pain prevalence at long-term follow-up after TPLO

Answer 136

Role of Tibial Plateau Angle in Canine Cruciate Ligament Rupture - CT of TPA more reproducible than radiographs - positioning of the normal limb relative to the X-ray beam causes a significant overestimation of TPA - osteoarthritis, affect TPA measurement - conformation of the proximal part of the tibia also has significant impact on the cranial cruciate ligament rupture occurrence - Slocum and Devine12 > the mechanical tibial axis represents the gold standard for tibial plateau angle measurement, different measurement methods i.e. using proximal tibial axes have also been considered

Answer 137

There is a lack of class I level evidence in veterinary rehabilitation. This study supports therapeutic exercise and cold compression therapy for postoperative CCLD rehabilitation. Existing studies on other modalities (i/e Extracorporeal shockwave) are limited and demonstrate conflicting results. PROM, undrwater treadmill 4-8weeks postop

Answer 138

clarify the histological effects of tibial plateau levelling osteotomy on cranial cruciate ligament degeneration induced by excessive tibial plateau angle. Study Design Five female Beagles results suggested that excessive tibial plateau angle-induced cranial cruciate ligament degeneration can be suppressed by reducing the biomechanical load on the cranial cruciate ligament by performing tibial plateau levelling osteotomy, may delay or prevent chondrometaplasia of the cranial cruciate ligament. - outcome may differ from that of common ‘cruciate disease’ cases.

Answer 139

Prospective cohort study, 130 stifles A total of 41 stifles (31.5%) had a negative meniscal flounce. Of these stifles, 38 had a meniscal tear sensitivity, specificity, positive and negative predictive values, and diagnostic accuracy of the meniscal flounce sign for indicating an intact or torn meniscus were 96.6%, 90.5%, 95.5%, 92.7%, and 94.6%, respectively. The absence of the sign strongly indicates the presence of meniscal pathology. The meniscal flounce, a fold in the free, unanchored inner edge of the medial meniscus, is a common arthroscopic finding in dogs In people, the absence of a meniscal flounce is a strong predictor of the presence of a medial meniscal tear

Answer 140

Ex vivo. Meniscal Load and Load Distribution with TPA of 6 and 1 Degrees Kinetic data between the intact and 6 degrees TPLO no significant changes, significant reduction in load on the menisci 1 degree TPLO caudal tibial motion after TPLO was present, but the effect was not significant. Kim and colleagues reported that the peak pressure location moved caudal in CCL-insufficient stifles and remained at a caudal location after TPLO quadriceps force also creates cranial tibial thrust > reduced after TPLO, because the patellar ligament angle will be close to 90 degrees after TPLO at a 135 degrees stifle angle.

Answer 141

Comparison of Two Stifle Exploratory Methods Using Mini-Arthrotomy. Cadavers. stifle distractor (SD method) or a combination of Hohmann and Senn retractors (HS method) Correct diagnoses 24/30 for both methods for observer 1; and in 17/30 and 19/30 cases for observer 2 respectively. There was no significant difference in the correct diagnosis correct diagnosis of the lesions was achieved in up to 80% of cases Correctly diagnosing meniscal tears > type and location, surgeon’s experience and the instruments and methods used for diagnosis.

Answer 142

Cadavers. Compression through Fragment Rotation during TPLO In all adequately rotated > significantly reduced caliber of the cranial tibial artery on the level of the osteotomy = 81%. hemorrhage dt laceration cranial tibial artery or by multiple small branches reaching craniolaterally * study to show what happens if pack that area?

Answer 143

retrospective, TPLO in small and big dogs meniscal injury at isurgery was 38.2% small and 36.7% in medium-to-large dogs. The subsequent meniscal tear rate was 1.3% in small dogs and 8% in medium-to-large dogs. The difference not statistically significant Degree of cruciate ligament insufficiency and use of arthroscopy were significantly associated with tear

Answer 144

94% injury to caudal cruciate in stifles with cranial cruciate disease - partial longitudinal tear most common - correlated with synovitis - only synovial covered CaCL affected → authors suggest synovitis → CaCL injury

Answer 145

Cadaver study + 9 cases. rotation of tibial plateau segment and closure of pes sufficient for hemostasis after cranial tibial artery transection during TPLO elevation of the soft tissue envelope and packing may induce haemorrhage through direct vessel injury+/- periosteal blood supply impacting bone healing. severe intraoperative bleeding despite gauze packing reported. Ellis pin ‘handle’, large enough to ensure rotation and tight apposition of the osteotomized fragment. Kirschner wire engage the trans-cortex, 1.6 to 2mm Bleeding from the screw holes > insertion of the screw without delay.

Answer 146

A Gelpi retractor was introduced tangentially and approximately at middistance of the osteotomy line between the tibial fragments temporary digital pressure was applied on the medial aspect of the thigh at the distal third to fourth of the femur. This maneuver compressed the distal femoral artery 2 suction tips were used Moles and Glyde9 have described a surgical approach in cadavers to allow temporary occlusion of the popliteal artery proximal to the stifle joint to decrease blood loss and improve visualization while the surgeon attempts to control hemorrhage. This technique requires exposure of the cranial tibial artery just proximal to the medial femoral condyle in the popliteal fossa by separating several muscles

Answer 147

Ex vivo randomized blinded computed tomographic angiographic study. Sample population: Fifteen pelvic limbs evidence that flexion of the stifle during completion of the TPLO does not appear to result in movement of the cranial tibial artery away from the caudal proximal tibia.

Answer 148

362 dogs, retrospective Prevalence of bilateral meniscal tears was 48.0% breed, older age, lower patient weight and complete cranial cruciate ligament tear were significant risk factors only open arthrotomies were performed to identify meniscal tears. This result indicates that when a meniscal tear is identified in the first stifle, the chance of a tear in the other stifle ismore than 50/50. In fact, our results indicated a 72% chance. Thus, a tear in one stiflemakes a tearmore likely on the contralateral side

Answer 149

Retrospective. 176. Bilateral Simultaneous vs Staged TPLO with Arthroscopy complication rate 47.5% for SIMultaneous and 19.5% for the Staged major complications 10.1 and 3.8% in the SIM and ST Tibial tuberosity fractures 2% of the SIM group and none of the ST found no significant differences in the rates of short-term major complications, the risk of minor complications with SIM is increased incidence of simultaneous bilateral disease at the time of presentation has been reported between 8 and 14% conflicting results in literature > many suggest increased TT # and SSI with SIM sx.

Answer 150

retrospective case comparison study mini-TTTA vs ECS+TTT - no significant difference in clinical outcome at 8w - mini-TTTA → 1/27 reluxation, ECS+TTT → 5/26 major complication (failure/explant) - - TPA >30 not a limitation for miniTTTA Outcomes were mainly evaluated subjectively

Answer 151

n 120, retrospective Cartilage pathology and synovitis were identified in all joints. Overall cartilage severity scores were low (median MOCS 1). The median MOCS of the proximal trochlear groove (2) was significantly higher lesion consistent with altered mechanics of joint post CCLR > increase in peak pressure magnitude and a decrease in the contact area between femur and tibiawere identified, aswell as a shift of this contact area to a more caudal location medial meniscal tear had no association with cartilage severity scores or synovitis cartilage lesions are common in dogs with CCL disease at the time of surgical intervention, MOS subjective assessment

Answer 152

9 dogs, kinematics following LFTS for CCLR in medium to large breed, short-term outcome cranial tibial translation decreased from 9.3 mm > 7.6 mm after LFTS but remained increased compared with control > demonstrated the limited ability of nylon LFTS to stabilize CCL-deficient stifle joints in medium- to large-sized dogs. axial rotation and stifle joint flexion and extension angles were not significantly different from control laxity after LFTS has been reported in 24% to 45% of cases paradoxical findings of improved lameness with ongoing instability highlight the poor overall understanding of joint-related pain

Answer 153

short-term. Retrospective. immature16 stifles. CBLO. Mean age 6mths. (TPA) 9 postoperatively, (last rads only at osteotomy healing 6-8 weeks post op > unknown effect as adult on tibia conformation) one proposed advantage of CBLO – avoidance of proximal tiabial growth plate - recurvatum induced by overcorrection in 1 dog - valgus deformity in 2/15 due to plate screw engaging distolateral aspect of prox physis → full function after revision - full function in 15/15 dogs, clinical assessment median 23months. apophyisis remained open with k-wires bt not with compression screw.

Answer 154

Most dogs in our fracture group presented with lameness, but others were identified incidentally on routine follow-up radiographs. Kanno et al. showed that shortening of the patellar ligament moment arm (PLMA) with TPLO, as occurs when the intercondylar eminence is shifted cranially, increases the tensile force of the quadriceps studies demonstrate disruptions to normal patellar kinematics and forces following TPLO which could additionally increase stress on the patellar ligament

Answer 155

Experimental Purpose-bred beagle dogs (n = 15). Subsequent meniscal tears following TPLO or TTA Radiographic osteoarthritis scores of TTA higher than TPLO stifles at 12 weeks > no difference at 32 weeks postoperatively. Subsequent medial meniscal tears: 6/10 TTA stifles, and 0/10 TPLO at 12 weeks , 5/5 TTA stifles, and 1/5 TPLO stifles at 32 weeks postoperatively. experimental model, TPLO protects the medial meniscus and articular cartilage better than TTA clinical studies reported persistent cranial tibial subluxation in 70% and 100% TTA Lameness scores were not different between TTA and TPLO limbs at any time point (only subjective assessment) only one dog lame, findings may challenge the dogma that meniscal tears are overtly painful and > potential underestimation of subsequent meniscal tears Another clinical dilemma arising from our findings is whether treating a subsequent meniscal tear is universally indicated.

Answer 156

Retrospective, 30. Synovial biopsies synovitis scores were similar regardless of degree of rupture or meniscal injury and were characterized by hyperplastic and lymphoplasmacytic synovitis Humoral immune responses may play key roles in the synovitis associated with CCLD. clear evidence that synovitis plays important roles in this whole-organ disease in dogs and in man.7-9 Synovitis is linked to increased cartilage damage in dogs and in man10,11 and is considered a potential predictive factor for severity and progression of OA

Answer 157

Retrospective study. 100 cases; value of routine post op rads TPLO At routine rechecks of dogs with no owner-perceived issues after TPLO, 49% had minor complications but only 2% were deemed significant enough to alter patient management. 2%) > patellar ligament desmitis were recommended to continue exercise restriction for an additional 2 weeks The value of routine radiographic recheck examinations should be considered in TPLO cases with unremarkable clinical recoveries.

Answer 158

26, prospectively randomized – TPLO vs TTA-Rapid → no difference in long term outcome or complications. - TPLO → more lameness at d1-3 post-op conflicting outcomes reported in comparison studies, difficult to compare. many are retrosepctive

Answer 159

cases series. Fifty-two surgical procedures performed in 45 dogs Intraoperative complications occurred in two stifles. No postoperative complications were recorded and all osteotomies healed uneventfully. A limitation of the study was that the mMPTA was measured using the conventional method described by Dismukes and colleagues because it was the only one validated at the time of our first cases.16 The tangential method described by other authors has been shown to be more accurate. ( This was accomplished by raising the distal aspect of the tibia until the angle between the radiographic table and the mechanical axis of the tibia was equal to the measured TPA) it has been shown that experimentally induced valgus deformity of the proximal tibia in Beagles leads to the development of osteoarthritis

Answer 160

12-month survival of intra-articular, decellularized allografts arthroscopy, 45% survive at 12 months after surgery. - outcome: owner assessed (improved by 62.5%), GRF (34.4%) in all dogs - intact graft → more likely to have successful outcome (100% vs 50% of torn grafts based on GRF cutoffs)

Answer 161

Exploratory arthroscopy revealed moderate degeneration of the caudal cruciate ligament in all 3 dogs; the cranial cruciate ligaments were grossly normal. Corrective osteotomy to increase the tibial plateau angle was performed in 1 dog, and the lameness resolved by 2 months after surgery. The 2 other dogs were managed without additional surgery. One dog was persistently lame. The other dog reportedly had normal limb function 2.5 years after undergoing exploratory arthroscopy. Isolated degeneration of the caudal cruciate ligament should be considered as a differential diagnosis for Basset Hounds with lameness originating from the stifle joint

Answer 162

randomized clinical trial, Comparison of liposomal bupivacaine and 0.5% bupivacaine periarticular soft tissue injection for TPLO Dogs administered LEB were less likely to require rescue analgesia and received lower amounts of opioids than dogs administered 0.5BH. 3/14 dogs compared to 10/14. Opioids are the most effective drug class for the management of acute pain in small animals > dysphoria, nausea, regurgitation, and vomiting. Epidurally administered opioids have been shown to provide analgesia in dogs after TPLO Peripheral nerve blocks have similar efficacy to that found for epidural but with potentially fewer adverse effects.6 extended-release liposomal formulation intended to provide analgesia for up to 72 hours

Answer 163

to determine if breed or gonadectomy had a significant association with abnormal TPA. Study Design This was a retrospective case study. USA The average preoperative TPA was 29° neutered dogs have a significantly higher TPA than intact dogs A retrospective study in 2014 concluded that prepubertal gonadectomy of Golden Retrievers had a three to five times higher incidence of developing joint diseases than intact dogs.45 These authors followed with an additional study,46 reporting that German Shepherd Dogs gonadectomized before 12 months of age had an increased risk for cranial cruciate ligament insufficiency compared with sexually intact dogs.

Answer 164

12, <15 kg, up to 6mths post-op. Force Plate Gait Analysis for TPLO reached a near normal value at 6 months after surgery. It was suggested that TPLO for small breed dogs had good outcomes based on force plate gait analysis Complications = two cases relative tibial tuberosity width were 6.9mm rotated beyond the point of patellar ligament insertion in (50%). Symmetry index used to evaluate forelimb or hindlimb symmetry sample size, lack of arthroscopic confirmation of normalcy of the contralateral stifle, no control

Answer 165

prospective, 61, TPLO vs MMP no statistically significant difference in outcome or major complications with TPLO vs MMP - TPLO → more dogs reached ref range pVF at 3m → more dogs reaching higher mean pVF and VI at 6m (similar to control group) - complications: overall 13.2%, MMP → 3.17x higher risk of revision MMP represents an alternative to TPLO in evaluated breeds between 20 and 35 kg bodyweight.

Answer 166

Examination for meniscal click before anesthesia was **38% sensitive and 94.5% specific**, A meniscal click is more commonly associated with a meniscal BHT than with a non-BHT.

Answer 167

retrspective, 37 dogs with BSSTPLO and 18 with STPLO (staged bilateral) major complications for BSSTPLO and STPLO was 7/37 and 6/18 No significant differences. Locking implants. No tibia fractures in staged group, whereas tibia and tibial tuberosity # occurred in bilateral. » possible that BSSTPLO results in a higher prevalence due to forced early weight bearing 12.4 times higher odds of having fracture during BSSTPLO with conventional plates single longer episode of anaesthesia ismore or less safe than two separate anaesthesia events is difficult to prove.

Answer 168

Experimental TPLO . TPLO influences the tension of the collateral ligaments and might generate laxity of the tibiofemoral joint. Instability after the osteotomy might be associated with the progression of osteoarthritis. In the proximal compression test, craniocaudal displacement was not significantly different among the control-intact, TPLO-intact and TPLO-CrCL-transected. TPLO should be performedwhile the CrCL is still partially functional to slow the progression of postoperative osteoarthritis.

Answer 169

Fibular osteotomy to facilitate proximal tibial rotation during TPLO. Retrospective TPLO-FO (n = 23) , routine TPLO (n = 49). synostosis was identified as a radiographic ossification bridging the proximal tibiofibular joint double plate to reduce rockback of TPA. complications: mild lateral collapse of the osteotomy site valgus deformity + transient peroneal neurapraxia The fibula > poor or undetectable healing was diagnosed in 45% of cases.

Answer 170

the tTTA was less than the corresponding cage sizes by at least 1.5 mm in all but the 6-mm cage. The 6-mm cage resulted in a median tTTA of 4.3 mm, but it was not significantly different from 4.5 mm. The underadvancement measured in this study was greater in magnitude compared with previous studies Selection of a larger cage size during the TTA may be advantageous to compensate for underadvancement and to minimize the risk of residual cranial tibial translation.

Answer 171

320 dogs that underwent unilateral or bilateral TPLO (n = 405 procedures An SSI developed in 8.4% Infections were noted a median of 21 days (IQR, 14 to 61 days) Staphylococcus pseudintermedius SSI following TPLO was associated with the German Shepherd breed, meniscectomy, and surgeon. Prospective studies are needed to investigate the mechanisms underlying these associations Prophylactic antimicrobial administration following surgery was not significantly associated with SSI development in the present study, although a protective effect has been identified in previous studies. Nonetheless, in the absence of convincing evidence to the contrary, we recommend targeted prophylactic antimicrobial treatment following surgery for dogs at risk or suspected to be at risk of SSI, such as GSDs, dogs with complete cranial cruciate ligament rupture and meniscal tears, or dogs with perioperative dermatitis.

Answer 172

Locking fixation of TPLO with a 3.5-mm broad TPLO plate alone should be considered in large dogs because it may reduce complications.Retrospective case series. Sample population: Dogs (N = 287, Locking fixation eliminated the association between weight and complication rate. Conclusion: Locking fixation of TPLO with a 3.5-mm broad TPLO plate alone should be considered in large dogs because it may reduce complications.

Answer 173

Effect of the Centre of Rotation in TPLO on Quadriceps Tensile Force: An Ex Vivo The distally centred group had increased tensile force, which may cause patellar ligament thickening after TPLO. change in the PLMA is minimized and the cranial tibial displacement after TPLO is reduced by setting the osteotomy centre on the intercondylar eminence.

Answer 174

functional anatomy of the CrMd and CaLt bundles of the CrCL - CrMd band attached widely to the cranial intercondyloid area - centre of CdLt attachment site craniodistal to CrMd on the femur, caudal on the tibia - femoral and tibial attachments of CrMd larger than CdLt - tension of CrMd higher than CdLt, tense throughout ROM of the stifle - suggesting that the CrMB greatly contributes to the maintenance of tension in the CrCL in dogs

Answer 175

12 weeks, thigh diameter 91% no lameness, 2 complications Cranial tibial thrust was observed in three of 35 limbs (9%) on 2/25 had mensical tear at surgery.... how many develop at long term??? significant loss of extension Failing to reach a 90° patellar tendon angle can cause instability and predispose dogs to lameness certain challenges associated with the use of this technique in small dogs. The plate, as in medium or large dogs, should be positioned parallel to the cranial border of tibial crest need for over-contouring the distal part of the plate (17 of 20 dogs) because of its long neck; consequently, the screws must be inserted from the caudal tibial cortex.

Answer 176

retrospective, 100 dogs (113 limbs) tibial tuberosity fracture was identified in 25/113 stifles (22%) fracture within 6 weeks of surgery was postoperative cortical hinge width (CHW) of 5.5 mm cut-off value use pin and tension band to reduce risk. None of the dogs that developed postoperative tibial tuberosity fracture in this study had repeat surgery

Answer 177

9 dogs, retrospective – modified TTO for correction of concurrent CCLR, tibial deformities or patellar lux - appropriate PTA and mMPTA correction - outcome: 77.8% no lameness, 11.1% (1/9) mild, 11.1% moderate lameness mMPTA correction was indicated in these cases? good-to excellent owner satisfaction. weh et al: TPLO with wedge postoperative surgical complications were documented in 21% of the cases, and all complications were considered major because they necessitated additional surgery

Answer 178

TTA → reduction in force on both menisci - 12mm advancement → normalisation of stifle kinematics at 135° and 145° extension - 9mm advancement failed to normalise kinematics

Answer 179

Treatment for meniscal tear results in a significant improvement in lameness, with postoperative outcomes at 6 months comparable with dogs with intact menisci. Despite having significant osteoarthritic lesions at all time points, the progression of osteoarthritis is similar between dogs with meniscal tears and those with intact menisci.

Answer 180

retrospective study of 831 19.1% of dogs that rupture first side at ≥8y develop contralateral rupture - age, Golden Retriever and Labrador breeds associated with contralateral rupture - risk decreases with age

Answer 181

1. maintain alignment of the osteotomy and the tibial plateau position during the insertion of locking screws, 2. no need for plate contouring, 3. directed fixed angle locking screws (to avoid articular penetration) 4. greater construct stability compared with plates fixed with cortical screws.

Answer 182

saw bones. Different Methods to Achieve Interfragmentary Compression application of point-to point bone holding forceps across the TPLO in combination with insertion of a load screw distally in the compression hole of the plate provided more even interfragmentary compression in comparison to other forceps engaging the caudal aspect of the proximal bone fragment and the cranial aspect of the tibial crest We do not know if they are maintained in the postoperative period. cortical load screw in the Combi hole generated interfragmentary compression across the more distal transverse of osteotomy > accompanied by loss of compression and widening more proximally,

Answer 183

Novel crescentic, medial-closing, medially translating, CBLO for lateral compartment stifle disease. 2 dogs. Boxers are reportedly over-represented, loss of meniscal function in lateral compartments results in a 145% increase in peak contact forces Proximal tibial valgus has been associated with an overload of the lateral compartment Tx > reduced pressure in the lateral stifle compartment by shifting the mechanical axis of the stifle medially. Although biomechanical testing is needed to prove this

Answer 184

Whilst the sit to stand test required a shorter time for collection of data than the walk test, it did not accurately identify all dogs with lameness associated with CCLR, and thus has relatively limited clinical utility in its tested form

Answer 185

Prospective case series. Study population: Client-owned dogs (n = 55) Sensitivity for identifying meniscal lesions was 0.62–1.00 and specificity was 0.70–0.96. Intraobserver agreement was 0.50–0.78, and interobserver agreement was 0.47–0.83 Diagnostic performance was suitable for identifying meniscal lesions. An effect of experience and learning was seen in this study. MRI, with a diagnostic accuracy of 86%–91% and sensitivity and specificity for medial meniscal tears of 91%–93% and 81%–88%, respectively

Answer 186

radiographic review of 100 cases with mCCWO planning as per Oxley 2013 - modified CCWO did not result in TPA 5° in most cases

Answer 187

Experimental ex-vivo study. Sample population: Ten cadaveric The mean iatrogenic articular cartilage injury (IACI) was 3.71 ± 1.78% of the area of the medial meniscus. Conclusion: The establishment of a caudomedial portal for CPM in canine cadavers was feasible and allowed to perform a partial caudal pole meniscectomy. iatrogenic injuries to MCL and caudal cruciate ligament in this cadaveric study, surgeons should be aware of the potential risk for these injuries Our results emphasize that a minimally invasive procedure such as arthroscopy is not without risks and strategies including joint distraction and use of small diameter instruments should be considered when the joint is too narrow.

Answer 188

Prospective. 26 needle arthroscopy was rapid, high accurate and caused low morbidity in dx of medial meniscal tears - 95% sensitivity, 100% specificity, ppv 100%, npv 85.7% small-bore arthroscopes performed outside the operating theater under local anesthesia. Other srudy suggest GA better for elbw and shoulder. visibility of the menisci was lower, and probing of the lateral meniscus was more difficult intra-articular assessment by arthotomy or SA is essential for every dog > such as debriding the remnants of the torn ligament and thoroughly inspecting articular surfaces

Answer 189

Experimental ex vivo study. TPLO- with extra-articular lateral augmentation neutralizes craniocaudal and rotational instability After TPLO, internal rotational instability was significantly increased (pivot shift) **prevalence of 30% of cases with residual subluxation after TPLO when walking** persistent joint instability accelerates the progression of osteoarthritis and the development of meniscal tears

Answer 190

Pilot, prospective case series. 10 dogs. use of a polyethylene terephthalate implant - outcome scores and ground reaction forces improved - 2/10 fully intact and function, 4 partial, 3 complete failure, 1 explant with infection - 3/10 ongoing sagittal instability possible that cyclic fatigue contributed to their mechanism of failure

Answer 191

locking 3.5/4.0-mm jumbo plate in dogs > 50 kg. Retrospective 24 stifles complications (45.8%) inclusive of 1 minor, 1 catastrophic, and 9 major complications. SSI 20% A statistically significant increase in TPA over the convalescent period was found postoperative antibiotic use with use of a placebo showed a significant association between risk of SSI and increasing patient size Double plating involves the addition of a second plate on the proximal tibia, caudal to the TPLO plate, Kowaleski precontoured locking > minor postoperative complications were reported in 3 of 56 (5.4%) patients, and no major or catastrophic

Answer 192

distance between the points of CCL origin and insertion (DPOI). Additionally, a novel variable, DPOI ratio, was evaluated. To assess the effect of tibial compression on radiographic cranial tibial translation measurements healthy and CCL dogs compared DPOI ratio values above 1.18 were consistently indicative of CCL rupture, thus allowing for a precise radiographic diagnosis of the condition One limitation of this study is that radiography was performed under no sedation or anesthesia of the patient

Answer 193

Seventeen dogs (mean weight, 12.3±5.1 kg before surgery (T0), one (T1), three (T3) and six (T6) months after surgery The clinical recovery after extracapsular stabilisation of the stifle joint was not associated with a spontaneous increase in physical activity or a decrease in sedentary behaviour no control group This major reduction of thigh circumference at T0, associated with restrictions and limited limb use in the first 3 weeks of the postoperative period, contributed to a delay muscle mass gain. As a result, the thigh circumference of the affected limb measured at T1, T3 and T6 did not change compared to T0. benefit of physiotherapy?? consideration is that dogs can be highly influenced by their owners’ habit

Answer 194

Complications and postoperative nsaid with extracap repair. Complications and nsaid use in patients weighing more than 15 kg. Age and weight appeared to be the most important factors > small and older dogs appearing to be most suitable 84% of patients recovering from surgery without complication. A large number of patients did require NSAID at least once in the period of 3 to 18 months postoperatively

Answer 195

Design Prospective clinical study. Methods Twenty-nine client-owned dog there is evidence26,27 that clinical outcomes after TPLO treatment may be influenced by the degree of cruciate ligament fibre damage at the time of surgery, particularly dogs with partial CR, where sufficient intact fibres prevent clinically detectable cranial tibial translation. Severity of joint laxity is best assessed under general anaesthesia. Such knowledge should reduce the risk of misdiagnosis and may enhance early diagnosis and treatment of dogs with CR over time.

Answer 196

1 year after implantation. Design Retrospective case series A biocomposite tibial tuberosity advancement cage was found to have variable amounts of radiographically apparent osseous integration at least 1 year after implantation.

Answer 197

(<20 kg) that underwent TPLO or LFTS TPA >30° 84 stifles long term: 100% TPLO good or excellent outcome compared to 4/8 (50%) in the LFTS group. no evidence of a difference in short-term post-operative outcome or owner subjective longterm outcome between treatment groups. 31.3% LFTS group required (NSAID), no dogs in the TPLO no evidence of a difference in overall major complication rates (13.3% LFTS vs. 14.8% TPLO) implant failure rate TPLO 9.3% (5/54). nonlocking used Late meniscal injury > surgical treatment in LFTS. none of the TPLO group Meniscal release (prophylactic or therapeutic) was performed in >40% (22/54) of dogs in the TPLO group; none of LFTS

Answer 198

Poor blood supply to the core region could be an important underlying condition for spontaneous degeneration of the CCL in at-risk dogs synovitis was often observed in specimens obtained from intact stifle joints in the study reported here, we suspect that these changes were related to factors apart from the initiation of CCLD because of a lack of a significant relationship with degenerative changes in the ligament. synovial inflammatory changes detected in stifle joints with CCLD could be a manifestation of the disease processes rather than a contributing factor, as has been suggested for some studies

Answer 199

The PLL was shorter after TPLO in dogs whether a decrease in ligament length results in decreased mobility and persistent lameness in dogs, as has been reported for humans?

Answer 200

Rabbit Tibiae: Distal Jig Pin Hole examine optimal distal jig pin position for (TPLO) procedure. If canine tibiae were similarly affected, our findings suggest jig pin placement in the Distal Metaphysis to have a lesser effect on the torsional properties of the tibiae and reduce risk of fracture resulting from the defect compared with a Mid Diaphyseal defect.

Answer 201

The þ4mm and þ6mm offset Fixin plates may be considered for TPLO-M in dogs weighing between 5 and 10 kg. The þ6mm offset plate should be used cautiously in dogs weighing less than 10 kg since this plate may result in insufficient postoperative bone apposition at the osteotomy site. increased in plate to bone distance, which may result in weakening of the bone-plate construct Medialization of the tibial plateau resulted in a small but not significant change in mMPTAvalues inmost of the study groups.

Answer 202

virtual surgical correction for eTPA - mCCWO → moderate alteration to tibial geometry, preserves osteotomy overlap - TPLO+CCWO → least alteration to tibial morphology but most unstable construct - coplanar CBLO → most alteration to tibial morphology cranial closingwedge ostectomy (CCWO), modifiedCCWO (mCCWO), isosceles CCWO (iCCWO), neutral isosceles CCWO (niCCWO), tibial plateau levelling osteotomy with CCWO (TPLO/CCWO) and coplanar centre of rotation of angulation- based levelling osteotomy (coCBLO). outcome measures included tibial long axis shift (TLAS), cranial tibial tuberosity shift (cTTS), distal tibial tuberosity shift (dTTS), tibial shortening and osteotomy overlap

Answer 203

compare the standard fabellotibial suture with Mini TightRope fixation Fixation of CCL-deficient stifles with lateral fabellotibial suture, as well as Mini TightRope tightened with a 20 N load, produces good biomechanical stability, as detected via radiographic assessment The TightRope should reduce internal rotation without leading to external rotation, and is placed at more isometric points than techniques used previously neutralised excessive cranial tibial thrust in cats that underwent experimental CCLT unable to prove that the Mini TightRope technique is associated with less external rotation than standard fabellotibial suture

Answer 204

Pozzi 2010 – transection of caudal meniscotibial ligament → 50% decrease contact area and 140% increase in peak pressure in the medial compartment - loss of caudal meniscotibial ligament → elimination of load bearing function of meniscus - medial meniscal release contradictory to surgical stabilization of CCL-deficient stifle Pozzi 2008 – medial meniscal release and caudal, pole hemimeniscectomy → 2.5x increase in %surface area with pressure >10MPa - CCL transection → altered pressure distribution without TPLO and caudal shift of load - TPLO → MMR and MCH increasing %surface area by 1.7x Pozzi 2006 – medial meniscal release had higher effect on tibial translation in CCL-transected and less effect after TPLO - medial meniscus resists tibial translation → risk of injury in CCL-deficient stifle - TPLO may have a protective effect on medial meniscus - neutralization of cranial tibial thrust and elimination of wedge effect

Answer 205

- TPLO 1-12.3% - TWO 5% - TTA 3.1-27.8% - TTO 3.1% - CTWO 4.5-5.4% - ECR 1.9-6.3% insufficient evidence to recommend one stabilisation technique or meniscal procedure

Answer 206

To assess whether tibial tuberosity avulsion injury and subsequent surgical repair in skeletally immature dogs are associated with changes in tibial plateau angle (TPA) at skeletal maturity. Methods: Skeletally mature (> 18 months of age) associated with a smaller TPA at skeletal maturity compared to non-operated stifles. However, causality cannot be established from this cross-sectional study, and this association may be because stifles with a smaller TPA are predisposed to tibial tuberosity avulsion.

Answer 207

18 stifles in dogs with CrCL and an eTPA (>34°), first 120 days post-op TPA 6.3° (3°–13°) Minor complications (not requiring surgical review or clinical treatment) were observed in 4/18 of stifles Jig used 9.1 kg (range: 5.0–20.4 kg) gap in the cranial region of thewedge in stifles 4 and 8 patellar ligament thickening was noted in 16/18 stifles during theimmediate postoperative period. An increase in thickness was observed in 13/18 stifles at 30 days and in 11/18 stifles at 60 days A change in the final TPAwas observed in 5/18 of stifles

Answer 208

Retrospective. 87 dogs. Effect of Plate Inclination and Osteotomy Positioning on Rock-back Rockback was identified in 21% (increase in TPA of 2 degrees) Plate inclination and ECA were not correlated risk factrs for rock-back remain largely unknown and warrant further research. Anecdotal > craniodistally eccentric positioning of implant may predispose patients to rock-back

Answer 209

Stifle flexion angle influences femoromeniscal contact mechanics significantly > As the knee flexes, the load on both menisci increases. performing TPLO rotates the tibial plateau and therefore changes the position of the menisci in relation to the femur to different degrees, depending on joint flexion angle

Answer 210

Retrospective. 43. short-term outcomes and complication meniscal suturing and (TPLO) +/- extracapsular suture. All meniscal pathology involved the caudal (Cd) horn of the medial meniscus only (LOAD) scores, and second-look arthroscopy > short term. Complications (34%). TPLO + IB had a 93.3% success rate > 71.4% in the TPLO-only group. Postoperative stifle stability had an impact on successful treatment. 8 weeks > needle arthroscopy (66%). Fraying of edge/small complex tear n = 8 6 failures > dx on clinical exam. lack of comparative data representing dogs with intact menisci or receiving meniscectomy is also a significant limitation.

Answer 211

Retrospective. 78 dogs. Tibial fracture associated with use of Arthrex self-tapping screws Evidence of a TCTF in 42% (33 of 78) TCTFs were only identified distal to the osteotomy. 6% (2 of 33) required surgy dt complication Use of Arthrex 3.5 mm STS for TPLO is associated with risk of TCTF in contrast to use of non-self-tapping screws, particularly if screws are not placed perpendicular to the plate. Screw angulation > cutting flute partially cutting thorough the tibial cortex large TCTF or a propagating fissure > external coaptation or pre-emptive internal fixation because of high risk of complete tibial fracture. cutting flutes become filled with bone during placement through the cis cortex, and that the subsequent reduced cutting leads to TCTF fracture

Ch 61a Stifle: CCL Flashcards

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