Exam 1 Flashcards

Question

Plate and Screw Fixation They carry ALL applied loads during early postoperative period

Answer 1

-Ideal for complex or stable fractures, when prolonged healing (bone union) anticipated or when optimal postoperative limb function desired. 1. Compression plate: transverse fractures 2. Neutralization plate: long oblique fractures, with lag screws 3. Bridging plate with or without IM pin: non reducible fracture Type of crews -Cortical -Fully threaded cancellous -Partially threaded cancellous Types of Plates -Buttress: prevents collapse of adjacent articular surface -Locking plate: Locking screws hold bone in that position Applying bone plates -Need to span the bone length for diaphyseal fractures -Accurately contour not locking plate -3 screws or secure 6 cortices above and below fracture -Longer and stronger for bridging plates with IM pin Lag Screws -Compress fracture line between 2 bony fragments -Into plate or directly into bone -Perpendicular to fracture line -Bisect angle 90 degrees -Hole in near cortex: GLIDE HOLE, outside diameter equal to thread of screw -Hole in far cortex: inner core diameter or shaft of screw equal to hole *Reduce and secure fracture before placing lag screw* *optimal compression: screw perpendicular to fracture* *Drill near cortex: bit equal to screw thread* *Drill far cortex: bit equal to screw core diameter* *Partial threaded screws should not cross fracture* -Expose pin insertion site -Center pin in bone -Pre-drill pin hole -Insert pin with low RPM power -Release incision around pin to prevent skin tension -Pin drilled into bone at point of greates cross-sectional diameter Circular external fixators (RING) -Stabilizes fracture, compresses non-unions, distract fractures. -DISTRACTION of BONE SEGMENTS -Results in a new bone formation in trailing pathways, "distraction osteogenesis" -Small diameter tensioned wires. -Allow controlled axial micromotion at fracture site without compromising fixator stability.

Answer 2

1. List general indications for performing an amputation. 2. List the major techniques for performing a thoracic limb amputation and describe how each is performed. List which muscles are transected for each technique. 3. List the major techniques for performing a pelvic limb amputation and describe how each is performed. List which muscles are transected for each technique. 4. Describe the surgical procedure used for performing a caudectomy. 5. List the major complications seen with amputations and discuss steps to avoid these complications. 6. Discuss steps considered when determining if a patient is a good candidate for limb amputation.

Answer 3

1. Tail: traumatic lesions, infection, neoplasia, reconstructive surgery (lateral caudal axial pattern flag), breed standards -Treatment: change environment, bandaging, topical treatment. Caudectomy (last resort) -"Tail beater" amputation when bandaging is ineffective or impossible. Procedure 1. make elliptical incision around base of tail 2. Incise subcutaneous tissues to expose muscles 3. Separate attachments of levator ani retococcygeus, and coccygeus muscles to caudal vertebrae. 4. Transect tail by disarticulation at second or third caudal vertebra 5. Ligate medial and lateral caudal arteries and veins. 6. Appose levator ani muscles and lavage site. 7. Appose SQ tissues in simple interrupted or continuous pattern with monofilament absorbable. 8. Excise redundant skin if needed 9. Apose skin edges, 3-0 nonabsorbable sutures. -Amputate through disc space -Generous skin flaps - dorsal flap larger (longer) -Hemorrhage control -PAIN CONTROL -Ear pinna (not covered) -Digits -Penile (not covered) -Thoracic limb -Pelvic limb

Answer 4

Indications -Neoplasia -Trauma -Neurological impairment: radial nerve paralysis, Brachial plexus injury Types 1. Forequarter -Skin incision dorsal border of scapula over scapular spine to proximal third of humerus -continue around the limb -Transect trapezius and omnotransversarius mm at insertions on scapular spine. -Transect rhomboideus m from attachment on dorsal border of scapula. -Elevate serratus ventralis m from medial surface of scapula -Retract scapula laterally to expose axillary artery and nerve for ligation -Transect brachial plexus, latissimus dorsi m near humeral insertion -Block brachial plexus. -Three-forceps transfixation suture technique: three forceps on artery and ligate in crushed area proximal forceps. Transfixation ligature distal to first ligation and cut vessel between middle and distal clamps. -Transect brachiocephalicus, deep and superficial pectoral mm near humeral insertions and remove forelimb. -Closure: approximate muscle bellies to cover brachial plexus and vessels and suture SQ and skin. -Apply soft padded bandage 2. Midhumeral -Skin incesion around forelimb at level of distal third of humerus -Reflect skin -Abduct limb and separate biceps brachii m and medial head of triceps -Expose brachial artery and vein for ligation. 3 clamp technique. -Median, ulnar and musculocutaneous nerves for transection -Transect triceps tendon -Cut biceps brachii and brachialis mm at insertions on radius and ulna. -elevate brachiocephalicus m from humerus. -Ligate cephalic vein and transect radial nerve -Osteotomize humerus and remove limb

Answer 5

Indications -Neoplasia -Trauma -Neurological impairment: sciatic nerve femoral nerve injury/impairment Coxofemoral Disarticulation -Make skin incision around rear limb at level of middle third femur -On medial side: open femoral triangle by incising between pectineus muscle and caudal belly of sartorius muscle. Expose and ligate deep femoral artery and vein: 3 clamp technique -Transect sartorius, pectineus, gracilus, and adductor mm. ~ 2cm from inguinal crease -Transect Iliopsoas m at intersection on lesser trochanter and reflect cranially to expose joint capsule -Incise joint capsule and cut ligament of head of femur -On lateral side transect biceps femoris m and tensor fascia lattae at midfemoral level -Severe sciatic nerve distal to muscular branches -Transect gluteal muscle close to greater trochanter -Transect semimembranosus, semitendinosus mm at proximal third of femur. -Cut external rotator mm and quadratus femoris m at attachments around trochanteric fossa -elevate rectus femoris m from origin on pelvis -Remove limb Midfemoral amputation -Skin incision around rear limb at level of distal third of femur -On medial side: transect gracilus, caudal belly of sartorius at midfemur. -Isolate and ligate the femoral vessels: 3 clamp technique, transect pectineus m through musculotendinous junction, transect cranial belly of sartorius muscle. -Transect quadriceps mm group proximal to patella -Transect biceps femoris m at same level as quadriceps muscles. -Isolate and cut sciatic nerve at level of third trochanter -Transect semimembranosus, semitendinosus, and adductor mm at midfemoral level -Elevate insertion of adductor m from linea aspera of femur -Cut femur at junction of proximal and middle thirds of diaphysis and remove limb.

Answer 6

CHD -Hereditary developmental condition of the coxofemoral joint (hip) that leads to degenerative joint disease (DJD) - The most prevalent genetic based orthopedic disease of dogs Definition: abnormal, characterized by subluxation or incomplete luxation of femoral head in younger patients and mild to severe DJD in older patients HIP LAXITY **Young dogs: is painful, wear of articular cartilage exposes pain fibers in subchondral bone. Laxity causes stretching of soft tissue** **Older dogs: hip dysplasia causes pain through osteoarthritis**

Answer 7

Cartilage damage Osteophyte formation Subchondral Sclerosis -Luxation: complete separation between femoral head and acetabulum -Subluxation: partial or incomplete separation between femoral head and acetabulum

Answer 8

Exercise intolerance clinical signs often do not correlate with radiographic findings Some dogs with moderate or severe dysplasia are asymptomatic

Answer 9

-Hereditary: pylogenetic multifactorial -Environmentally influenced -HIPS NORMAL at BIRTH -Restricting growth rate can reduce onset, severity and incidence of CHD. -CHD can not be eliminated, only reduced by breeding only dogs with normal hips. -Phenotypically normal dogs can produce dysplastic dogs. Large breed dogs -German shepherds, Rottweilers, Labrador, Retrievers, Golden Retrievers, Saint Bernards.

Answer 10

Hip Laxity -Decreases surface area of articulation, concentrating stress over a smaller area. -Favors development of CHD Physiological response to laxity -Increased joint fluid volume -Proliferative fibroplasia of joint capsule -Increased trabecular bone thickness Mechanical response to Laxity -Joint capsule stretching -Acetabular bone deformation -Periosteal nerve tearing -Sharpey's fibers rupture, bleed and form osteophytes -Microfractures of acetabular trabecular cancellous bone

Answer 11

-Round ligament -Joint capsure -Periarticular musculature -Capsular hydrostatic constraints -No structure is most important

Answer 12

-Sudden onset of unilateral lameness -Abnormal gait: short stride, bunny hopping. -Pain -Poor muscle development hind limbs -Joint laxity -Positive Ortolani Sign -Angle of reduction: measure point where femoral head slips back into acetabulum when limb is abducted. -Angle of subluxation: measured point where femoral head slips out of acetabulum when limb is adducted

Answer 13

-Chronic lameness, worse after exercise -Often bilateral lameness -Decreased muscle mass in pelvic limbs -Waddling gait Bunny hopping -Crepitus (granting or crackling sound) and pain on palpation -Rises slowly with difficulty -Shoulder muscle hypertrophy -Difficulty climbing stairs

Answer 14

Young dogs -Panosteitis -Osteochondrosis: osteochondritis dessicans -Physeal separation -Hypertrophic osteodystrophy -Cranial cruciate injury -Patellar luxation -Trauma Older dogs -Degenerative myelopathy -Cauda equina neuritis -Intervertebral disk disease -Lumbrosacral stenosis -Cranial cruciate injury -Polyarthritis -Bone neoplasia Diagnosis -Signalment: breed predisposition -History -Physical Exam -Radiography PE young dogs -Pain on external rotation and abduction -Poorly developed pelvic musculature -Exercise intolerance -Increased laxity by Barlow test (first part of Ortolani test-subluxation) -Ortolani test Postive sign PE Older dogs -Pain on hip extension -Reduced range of motion -Atrophy of pelvic musculature -Exercise intolerance -Crepitus on palpation

Answer 15

Yes OFA: orthopedic foundation of animals PennHIP Aspect evaluated: -Acetabular margin -Subluxation/luxation -Size, shape, and architecture of femoral head and neck. -Presence of exostosis or osteophytes -Subchondral bone eburnation

Answer 16

-Advise encourage, and establish control programs to lower disease incidence -Encourages and finances research -Receive funds and make grants OFA Dysplasia Contrl Registry -24 months or older to register -Positioning specific VD radiographs (hip extended view) -Film identification requirements -Evaluated independently by 3 radiologists based on breed, sex, and age. -Consensus report produced OFA Consensus Report 7 grades 1. Excellent hip conformation (normal) 2. Good hip conformation (normal) 3. Fair hip conformation (normal) 4.. Near normal (borderline) 5. Mild hip dysplasia 6. Moderate hip dysplasia 7. Severe hip dysplasia

Answer 17

VD Subluxation of femoral heads and minimal evidence of DJD -Typifying a candidate for triple pelvic osteotomy (TPO)

Answer 18

VD Advanced hip dysplasia and osteophyte formation -May be candidate for total hip replacement (THR) or femoral head osteoctomy, if clinical signs can not be managed medically

Answer 19

Tests non-physiological hip position Subjective/intra and inter-observer variation Lack of uniform reporting Influence of age on reliability Procedure for Radiograph -Extend hips and internally rotate tibias until patellas lie directly over trochlear grooves -Pelvis straght -Symmetric rotation of obturator foramina

Answer 20

-recognized need for accurate and early diagnosis of CHD -Objectives of selective breeding -Stress radiographic diagnostic method -Database/Registry -International network of hip evaluation centers Measures Maximal Passive Hip Laxity -Passive vs. functional laxity -On average shows 2.5 x >laxity than visible on hip extended view -Statistically predictive at 16 weeks of age Procedure -Sedation/anesthesia -3 separate radiographs 2 positions -Measurement quantified, report interpretation 1. Hip extended radiograph: hind legs in extension, hip extended view. 2. Compression radipgraph: hips placed in neutral stance position. Femoral heads gently seated into acetabula 3. Distraction radiograph: hips placed in same neutral position as compression radiograph. Special device (distractor) is used to reveal inherent joint laxity PennHIP Distraction Index -Measure of hip laxity -DI closer to 1.0 high degree of laxity -<0.3 unlikely to occur Criticism -Training -Certification -Mandatory submission of all films -Encourage positive ID

Answer 21

Factors influencing treatment -Patient's age -Degree of discomfort -Physical and radiographic findings -Client expectations -Finances 1. Medical conservative management: 75% of young patients return to acceptable clinical function -Complete rest 10-14 days -Moist heat -Physical therapy -Nosteroidal anti-inflammatory drugs -Chondroprotective agents? -Weight control -Exercise -NSAIDs: Carprofen (ramadyl), Derocoxib (Deramax), Meloxicam (Metacam), Previcox (Firocoxib). -Chondroprotective agents: Parenteral Polysulfated Glycosaminoglycans (Adequan), Glycoflex, Cosequin, etc. 2. Surgical treatment: when conservative treatment not effective. Athletic performace required, slow progression of DJD and enhanced probability of good long-term limb function.

Answer 22

Surgical Treatment 1. Triple Pelvic Osteotomy (TPO) 2. Femoral head and neck excision (FHO) 3. Total hip replacement (THR) 4. Pectineus muscle myotomy/myectomy (historical significance) 5. Juvinile Pubic Symphysiodesis (JPS)

Answer 23

Note axial rotation and lateralization of hemipelvis

Answer 24

a. Cemented canine THR parts: CFX femoral head, femoral stem, acetabular cup. b. Cementless canine THR implants c. Kyon THR

Answer 25

-Expose pubic symphysis with ventral midline incision over pubis. -Spatula electrode set at 40 watts

Answer 26

Traumatic displacement of femoral head from acetabulum -typically results in craniodorsal displacement of femoral head relative to acetabulum. Most affected animals due to trauma, motor vehicle accidents -Ventrocaudal displacements much less frequent. Femoral head may lodge with obturator foramen, associated with fracture of greater trochanter. -Round ligament of femoral head always fails completely. Maybe interstitial rupture, or ovulsion of ligament from fovea capitis. -Fibrous joint capsule completely torn for dislocation of femoral head. -Tear in joint capsule may be small rent through which femoral head is dislodged. Or completely fraying of entire capsule. TREAT A.S.A.P Early reduction = rapid return of nutrient source for articular cartilage Associated with trauma -Half of patients have major injury in addition to hip luxation -Careful PE before induction of anesthesia and treatment to identify current trauma.

Answer 27

-Carriage of limb in craniodorsal position -Paw beneath body and external rotation of stifle.

Answer 28

-Place thumb in space caudal to greater trochanter and externally rotate femur If joint intact, trochanter displaces thumb If joint luxated, trochanter rolls over thumb. Diagnosis -Position of greater trochanter related to Ilial Crest and Tuber Ischii

Answer 29

-Radiographs carefully evaluated -Avulsion of fovea capitis -Associated hip joint fractures -Degenerative changes secondary to hip dysplasia Spontaneous Luxation Secondary to hip dysplasia = POOR PROGNOSIS (pic)

Answer 30

-Acute subluxation or luxation of hip joint secondary to hip dysplasia -Femoral capital physeal fracture -Femoral neck fracture -Acetabular fracture Medical Management -Closed reduction: no surgical approach, attempted before open reduction -Open reduction: surgical approach manipulation -Animal anesthetized for closed reduction

Answer 31

1. Grasp limb near tarsus with one hand, place other hand under limb against body wall to provide resistance 2. Externally rotate limb and pull caudally, position femoral head over acetabulum 3. When femoral head lateral to acetabululm, internally rotate limb to seat femoral head within acetabulum. Closed Hip Reduction 1. Patient anesthetized 2. Rope or towel placed in inguinal area and pulled dorsally 3. Provide counteraction, grasping distal portion of limb and pulling in opposite direction 4. Distraction allows contracted tissues to stretch. Maintained distraction to allow femoral head align with acetabulum -One hand on greater trochanter and other hand on distal stifle or hock. -Reduce externally rotating the limb and applying firm and consistent distraction -Once femoral head over acetabulum. Limb internally rotated with hand on greater trochanter pushing caudally and slightly abducted. -Once reduction suspected, firm pressure applied to greater trochanter with vigorous range of motion of hip. This helps displace soft tissue and reduces hematoma formation in acetabulum Assessment -Palpation of landmarks: Ilial crest, tuber ischii and greater trochanter -Measure width of space between greater trochanter and tuber ischii, resoration o flimb length, comparison with contralateral normal limb helps

Answer 32

"Ehmer femur" -Used to prevent pelvic limb wt-bearing -Post hip reduction or acetabular fractures Closed reduction of Caudoventral Luxation -Patient in lateral recumbency -Limb held perpendicular to spine -Grasp limb near tarsal joint with one hand, use the other to stabilize body -Place traction on limb while simultanously abduction leg. -Pulls femoral head beyond medial rim of acetabulum -Then exert lateral pressure medial to hip joint -Positions femoral head lateral to acetabulum -Push proximally and allow femoral head to fall into acetabulum Close reduction, Place in Hobbles -at tarsus or stifle -~ 7 days

Answer 33

Capsular reconstruction -If joint capsule salvageable (rare) -Most cases: capsule can't be securely closed and additional stability needed. -Other reconstructive procedures performed to ensure hip stability for 3-4 weeks until capsular healing occurs Reconstructive procedure -Synthetic capsular with suture and bone screws or suture anchors -toggle pin placement -Additional stability gained by translocation of greater trochanter -Reconstruction of joint capsule as sole means of stabilization requires dorsal joint capsule identifiable, and normal conformation of hip joint. Capsulorrhaphy -Interrumpted sutures places apposed joint capsule Placement of prosthetic Capsule -Bone screws in dorsolateral acetabulum -Suture material passed from screws through predrilled tunnel in dorsal femoral neck and tightened. -Suture prevents craniodorsal reluxation -May be perfomred using suture anchors

Answer 34

-Drill hole centered through femoral neck -And through acetabular fossa -Attach multiple strands nonabsorbable suture to toggle pin -Made from Krischner wire -toggle rod now available -Pass toggle pin/rod through hole in acetabular fossa and pull to set pin/bar -Pass sutures through hole drilled in femoral neck -Reduce hip and secure sutures

Answer 35

-Prepare new site distal and slightly caudal to normal anatomic position -Stabilize greater trochanter in position with small pins and orthopedic wire (tension band)

Answer 36

-Wire exerts force that counters force of muscle contraction -Compresses fracture surface

Answer 37

-Ehmer sling to assit hip reduction in early period. Removed after 4-7 days -Very controlled physical rehab exercises -Cage confinement adequate for dogs Success rate good to excellent ~ 50% Poor prognosis -Patients with poor confirmation, secondary hip dysplasia or previous trauma -Reasonable to attempt closed reduction in patients with hip luxation -Clinical studies: success of surgery after failed closed reduction no different than in patients undergoing surgical reduction as primary treatment -Open reduction success ~85-90%, results do not favor any one reconstruction technique

Answer 38

-Non inflammatory aseptic necrosis of femoral head -Occurs in young patients BEFORE closure of capital femoral physis -Synomyms: Avascular necrosis, Osteochondritis dissecans of femoral head. -Management: FHO (femoral heand and neck excision), THR

Answer 39

1. The student will explain the grades of patellar luxation, summarizing the clinical exam findings associated with each grade. 2. Given that some combination of four basic techniques is used in the repair of medial patellar luxations, the student will list the four basic techniques and describe the major steps in the performance of each. 3. Given an illustration of a basic technique used for repairing a medial patellar luxation, the student will correctly identify the technique being performed. 4. The student will describe the known association between cranial cruciate ligament rupture and medial patellar luxation. 5. The student will list the components of the extensor mechanism of the stifle and summarize the normal anatomical relationship of those components that result in acceptable physiologic function of that mechanism. 6. The student will discuss the special anatomic considerations that factor into the repair of a medially luxating patella.

Answer 40

-Displacement of the patella from trochlear sulcus -Common cause of lameness in small breed dogs -Also occurs in large-breed dogs -Associated musculoskeletal abnormalities: medial displacement of quadriceps, lateral torsion of distal femur, lateral bowing of distal one third of femur. Femoral epiphyseal dysplasia. Rotational instability of stifle joint. Tibial deformity. Deformities: Distal femoral physis -pressure in medial aspect causes less growth -Less pressure in lateral aspect allows accelerated growth -Lateral bowing of distal femur -Abnormal growth continues while quadriceps displaced medially and physes are active **Degree of lateral bowing depends on severity of patellar luxation and patient's age at luxation.** -Medial displacement of quadriceps apparatus

Answer 41

-Seen with medial displacement of quadriceps apparatus -Result of abnormal on proximal and distal physes of tibia -Medial displacement of tibial tuberosity -Medial bowing (varus deformity) of proximal tibia -Lateral torsion of distal tibia.

Answer 42

-Articular cartilage is physis for epiphysis -Dogs with medial patella luxation have abnormal development of trochlear groove: varies from near-normal trochlea to absent trochlear groove. -Responds to increased or decreased pressure the same as metaphyseal physis. Increased pressure retards growth, decreased pressure accelerates growth. -Articulation of patella within trochlear groove puts physiological pressure on articular cartilage, retards cartilage growth. **Pressure by patella responsible for developments of normal depth of trochlear groove.** If lack of pressure = not enough depth in trochlea. -Immature patients with mild luxations, minimal loss of trochlear groove bc patella is normally positioned during development, but if severe luxation, then no groove, no pressure during development. Grade I patella is in groove. It can be forced out but comes back in immediately -Shows no lameness, incidental finding usually Grade II Patella is in groove. Sometimes pops out but it comes back in every time -Occasional "skipping", retinacular structures become stretched and develop non-weight bearing lameness Grade III Patella is NOT in groove. It can be forced in but comes out again, almost immediately. -Lameness varies from occasional skipping to weight-bearing Grade IV Patella is NOT in groove. It can't be moved back in w/o surgery. -Walks with rear quarters crouched position, due to inability to extend stifle joints fully -Patella is hypoplastic and may be found medially alongside femoral condyle. Dx of MPL -Signalment: SMALL and TOY-breed dogs -History: intermitent weight bearing lameness. Owners report dog ocassionally hold leg in flexed position for one or two steps. Grade IV have severe lameness and gait abnormalities. -PE findings: based on eliciting MPL. Classify grade is important -Diagnostic imaging **MPL more common than lateral (LPL) in large dogs, **

Answer 43

Grade I or II -Patella within trochlear sulcus or displaced medially -Care taken to properly position limb to eliminate artifactual appearing luxations. Grade II or IV -Standard craniocaudal and medial-lateral radiographs. show patella displaced medially. What radiographs may show -Varus or valgus deformities -Torsion of tibia and femur -Special views or CT in severe cases help determine specific type and degree of deformity. Coronal or sky view of femur.

Answer 44

-Not consistently seen -Arthrocentesis demonstrates changes compatible with osteoarthritis

Answer 45

-Surgery not warranted if asymptomatic older patient -Surgery recommended in young or if lame -Advised in symptomatic immature or young -Clients advised to observe for developmental of clinical signs attributable to MPL Surgery indicated at any age in patients showing lameness. Strongly advised in those with active growth plates, skeletal deformity may worsen rapidly. Techniques for growing animals should not adversely affect skeletal growth. -Bilateral grade IV MPLs may need multiple surgeries, may continue lame even after surgery due to severity of long-bone abnormalities. Techniques -TTT tibial tuberosity transposition -Medial restraint release -Lateral restraint reinforcement -Trochlear groove deepening -Femoral osteotomy -Antirotational sutures -Transposition or origin of rectus femoris. Basic Techniques -Trochlear Wedge or Block Recession: deepened groove. Medial retinaculum release may be necessary. Allows patella to stabilize in deepened groove -TTT: tibial crest/tuberosity transpositoin should be done. Realigns mechanical forces of extensor mechanism, unless major corrections of femoral and tibial deformity performed. -Medial fascial release (desmotomy) -Lateral Imbrication of joint capsule with sutures. Placement of fascia lata graft from fabella to patellar fibrocartilage. Excision of redundant retinaculum. **Combination of techniques required. Prone to fail without TTT** -Boimechanical abnormality is primary need patella and trochlear groove permanently realigned. -If mechanical forces pulling patella out of trochlear are not neutralized, retinaculum stretches even if reinforced, so reinforcement techniques alone not enough. Osteotomy of the Femur -Only when severe skeletal deformity present -Varus bowing -Medial torsional deformity of proximal tibia -Goal is to realign stifle joint in frontal plane. Make transverse axis of femoral condyles perpendicular to longitudinal axis of femoral diaphysis. -Requires special equipment and training Quadriceps mechanism: secondary stabilizer of stifle joint for cranial translation (cranial drawer) Chronic luxation of patella: may lead to increased stress on CCL and eventual rupture. Combination of CCL rupture and patellar luxation a relatively common finding, particular in small-breed dogs.

Answer 46

Extensor mechanism of stifle joint -Quadriceps muscle group: extends stifle and aids in stabilizing joint. Converges as patellar tendon on proximal patella. Continues distally as straight patellar ligament. -Patella: sesamoind bone, embedded in tendon of quadriceps muscle. Inner articular surface smooth and curved to articulate with throchlea. Normal gliding articulation of patella and trochlea necessary for maintaining nutrition for throchlear and patellar articular surfaces. Essential component of functional extensor apparatus. Maintains even tension during extension of stifle, acts as a fulcrum in a lever arm. Increases mechanical advantage of quadriceps muscles. -Trochlear groove -Straight patellar ligament **Patellar ligament must be identified before making parapatellar incision to enter joint.** Lateral capsule is stretched and thin, medial is contracted and thickened. Medial trochlear ridge and ventral surface of patella may be worn. Always check! Tibial tuberosity -Alignment of quadriceps, patella, throchlea, patellar ligament and tibial tuberosity must be normal for proper function. -Malalignment of any of theses structures may lead to patellar luxation. Patient positioning -Dorsal or lateral recumbency with leg hanging over end of table. Need access to lateral side. Deepening of trochlear Groove -Best to preserve as much of medial ridge as possible -Trochlear wedge or block recession

Answer 47

Trochlear wedge recession

Answer 48

Do not transect distal periossteal attachment Stabilize tibial tuberosity with 1 or 2 small K-wires Lateral Patellar Luxation Tibial Crest Transpositon -For lateral patellar luxations transpose tibial crest medially -Stabilize tibial tuberosity in new location with 1 or 2 K-wire and figure 8 wire screw. Release of Medial Joint Capsule -Medial thicker and contracted with grade III or IV -Capsule and retinaculum released allows lateral placement of patella -Placement of loose suture prevents iatrogenic lateral luxation. It should not close tissue gap. Lateral Imbrication -Reinforcement of retinaculum -Place suture through femoral fabellar ligament and lateral parapatellar fibrocartilage -Grade III and IV if patella mostly out of position. Retinaculum opposite side of the luxation will be stretched -Once patella is reduced-excise excess retinaculum and joint capsule allowing tight closure or arthrotomy. -Or close retinaculum with VEST-OVER-PANTS suture pattern: a horizontal mattress pattern. Tissues are overlapped instead of meeting end to end. Sutures pass trhough both layers at both edges. Post-Op -6-8 weeks restricted physical rehab exercises and leash walking -Radiographs at 6-8 weeks -Gradual return to normal

Answer 49

Conditions of the stifle Cruciate ligament-related conditions of the stifle General considerations Mechanism of injury Anatomy and physiology Diagnosis Treatment options

Answer 50

-Arthritis: continuum from growing dog. Avulsion of the long digital extensor. OCD stifle -Luxating patella -Cruciate: meniscal syndrome -Inflammatory joint disease -Neoplasia -Injury

Answer 51

-Cranial cruciate ligament injuries: The most common lesion in the canine stifle -Cruciate instability: the major cause of DJD in the canine stifle Dogs -Partial or complete degrees of rupture -CCLD: slow degenerative process, over a few months or years. NOT RESULT of TRAUMA -Invariable causes: Osteoarthritis, aging of ligament (degeneration), obesity, poor physical condition, conformation and breed. Important features of CCLD 1. >50% of dogs with problem in one knew will likely develop similar problem in other knee. 2. Partial tearing of CCL is common and progresses to full tear -All sizes and ages -UNCOMMON in CATS -FEMALE and NEUTERED at greater risk, unknown reason Breeds >risk -Rottweiler -Newfoundland -Stafforshire Terrier -Mastiff -Akita -St Bernard -Chesapeake Bay Retriever -Labrador retriever Breeds

Answer 52

-Patellar ligament -Cranial tibial ligament of the medial meniscus -Transverse ligament -Cranial cruciate ligament -Caudal ligament of the medial meniscus -Medial meniscus -Caudal cruciate ligament -Caudal ligament of the lateral meniscus -Meniscofemoral ligament -Lateral meniscus -Cranial tibial ligament of the lateral meniscus Ligamentous support of the Stifle -Medial and lateral collateral ligaments: limit medial and lateral movement of tibia -CCL and CaCL (caudal cruciate ligament): restrain joint motion. -CCL: restrain cranial displacement of tibia on femur, restrain hyperextension of stifle joint, limits internal rotation of tibia on femur, limits virus and valves motion in flexed joint. -CaCL: restrains caudal displacement of tibia on femur, restrains hyperextension, limits internal rotation... same as CCL **During flexion they twist on each other**

Answer 53

1. Cranial cruciate ligament (CCL prevents cranial translation of the tibia) 2. CaCL 3. Meniscus -Insert rows rupture CCL, tibia is displaced forward and crushes meniscus Partial rupture -Large caudolateral band: taut (pull tight) in extension NO DRAWER SIGN -Small craniomedial band: taut in all phases of flexion and extension. DRAWER during FLEXION Dx -May require advanced imaging MRI -Surgical exploration, arthrotomy, arthroscopy -Severe lameness not initially noticed especially if bilateral disease, difficult jumping and rising, decreased activity level -"Meniscal click" popping noise -Medial butters: palpable thickening of medial aspect of stifle, grossly or radiographically visible -Non-wt bearing if complete rapture or meniscus is torn Ddx -Canine hyp dysplasia -Patella luxation -Neurological disease IVDD -Bone/tissue cancer -Fractures, OCD, panosteitis etc. Loss of CCL results -Progressive DJD, loss muscle mass, decreased limb use, decreased performance -Synovial joint inflammation, production of osteophytes, meniscal damage. -Long-term impairment due to arthritis: loss of range of motion, stiffness, evidence of pain -Tearing of meniscus: frequently damaged. Excise damaged parts = PARTIAL MENISCECTOMY Examination/Screening -Palpation of knee -radiographs: do not show status of CCL, but assess joint effusion, degree of arthritis, aid in surgical planning, rule out neoplasia/concurrent disease. Loss of fat pad and destination of caudal joint -Cranial drawer test -Tibial thrust test -May need sedation but try without it first unless painful patients. Dexmedetomidine/Butorphanol combos -Range of motion: Pain on extension -Tibial compression test, cranial translation of tibia. Index finger over patella, fingertip on tibial tubercle -Sit test -Cranial drawer test: negative test does not rule out CCL tear

Answer 54

Treatment -Surgery recommended to slow down progression of arthritis and eliminate/minimize lameness -ALWAYS for LARGE BREEDS -CONSERVATIVE for SMALL BREEDS? Conservative therapy -<25lbs may get by without surgery, but DJD, meniscal damage, articular erosions still occur -Medication, exercise modification, joint supplements, braces/orthotics -Activity restriction -Anti-inflammatory Rehabilitation Therapy -Quicken recovery time from surgery, but not as an alternative generally Custom knee bracing/orthotics: new, temporary solution, not much known yet.

Answer 55

-Still progression of arthritis occurs -NOT completely restore normal joint anatomy and function -Arthritis is non-reversible disease **Perform ARTHROTOMY/ARTHROSCOPY in all surgical cases** -Extra-articular vs. intra-articular -Use technique most comfortable for you -Be prepare to alter procedure -You are NOT repairing the CRUCIATE, you are STABILIZING the joint -No technique prevents DJD -90% subjective evaluation of good to excellent results

Answer 56

-RARE as only injury -CCL and collateral ligament damage usually Dx -Caudal drawer movement -Tibia appears sublimated caudally due to muscle pull -Reduction of subluxation with drawer movement of tibia cranially -RADIOGRAPHS -Need to check for other injuries Surgery Techniques -Extracapsular: imbrication techniques are utilized. surgically correct all injuries simultaneously

Answer 57

-RARE as only injury -CCL and collateral ligament damage usually Dx -Caudal drawer movement -Tibia appears sublimated caudally due to muscle pull -Reduction of subluxation with drawer movement of tibia cranially -RADIOGRAPHS -Need to check for other injuries Surgery Techniques -Extracapsular: imbrication techniques are utilized. surgically correct all injuries simultaneously

Answer 58

-Acts as shock absorber -Aid in lubrication -Peripheral 15% vascularized, -85% nourished by synovial diffusion **Isolated meniscal injuries are rare** -Secondary injury due to stifle instability Anatomy -Attached to femur and tibia by 6 ligaments -Biconcave, semilunar discs of fibrocartilage -Medial meniscus firmly attached to joint capsule and medial collateral ligament -Lateral meniscus attached to femur, more movable-spares injury after CCL tear. -Cranial horn, Body, Caudal horn (lateral and medial sides) Injuries -MOST COMMON INJURY occurs to MEDIAL meniscus during abnormal internal rotation -Often associated with rupture of CCL -Due to excessive forces/crushing during instability -Result in meniscocapsular detachment, separation in substance of meniscus. -Caudal horn of medial meniscus most often damaged, can be folded. Medial femoral and tibial condyles crush and shear it during weight bearing -Radial tears: run in axial to abaxial direction -Circumferential tears: follow the curvature of meniscus at site of tear -Bucket handle tears: circumferential tears with separation of meniscus at site -Meniscal release: incision of medial meniscus intended to prevent future impingement and damage

Answer 59

1. Isolated lateral meniscal tears are RARE, usually with CCL. Meniscofemoral ligament prevents it usually Meniscal click: sound during palpation indicates injury -A meniscus may act as a wedge and prevent drawer movement in an acutely injured stifle Dx -Radiography -Arthroscopy -Surgical exploration Surgical treatment -Intracapsular or extra capsular reconstruction techniques: focus on re-creation of passive constraints of stifle joint (CCL, joint capsule fibrosis). -Corrective osteotomy: TPLO, TTA, TWO, and CBLO -Injury of contralateral ligament in >50% of cases, percentage increases if "injured joint" visible in radiographic changes -Depends on: surgeon preference, patient size and function, cost of procedure. -Nearly 90% success rate regardless of technique used -Intrascapular reconstruction: passing autogenous tissue through joint "over the top" method, passing tissue through predrilled holes in femur or tibia. Fascia late tissue used. Advantages: most closely mimic position and biology of original CCL. Disadvantages: invasive, tendency of graft to stretch or fail -Extrascapular: involves the placement of sutures outside the joint or redirect of lateral collateral ligament. Incorrectly referred to as imbrication sutures. Numerous patterns and combinations, origins and insertions. Significant effects on isometry of the joint. Sutures also secured from bone anchors, bone tunnels. Monofilament nylon or siding or leader line. Manufactured orthopedic wire. Braided orthopedic wire Sutures tied or connected with crimp, crimping suture alters biomechanics properties of loop.

Answer 60

-Extrascapular: involves the placement of sutures outside the joint or redirect of lateral collateral ligament. Incorrectly referred to as imbrication sutures. Numerous patterns and combinations, origins and insertions. Significant effects on isometry of the joint. Sutures also secured from bone anchors, bone tunnels. Monofilament nylon or siding or leader line. Manufactured orthopedic wire. Braided orthopedic wire Sutures tied or connected with crimp, crimping suture alters biomechanics properties of loop.

Answer 61

Advances insertion of lateral collateral ligament to prevent abnormal drawer and internal rotation of tibia -Done by advancing fibular head -Eliminates instability CCL-deficient stifle -Performed alone or combo -Point of insertion is lateral collateral ligament Free fibular head cranially and caudally from tibial epiphysis, advance fibular head and stabilize with small Steinmann pin and tension band wire. **Extreme care to identify and protect Peroneal nerve** True Imbrication Techniques -Performed by tightening fascia lata: vest-over-pants suture pattern -Partial excision and closure

Answer 62

-Passive constraints (ligaments, meniscus, joint capsule) -Active constraints (muscles and tendons) -CCL pasive to cranial tibial translation and internal rotation of tibia -Larger tibial plateau angle, greater force on cranial tibia during weight bearing -During weight bearing/load a vector force occurs in tarsus, creates a simultaneous force through patellar ligament to stabilize stifle -135 degrees plane almost parallel to patellar ligament a combination of forces in stifle **If slope of tibial plateau not anatomically oriented perpendicular to patellar ligament on weight bearing: tibiofemoral shear force occurs, CRANIAL TIBIAL THRUST FORCE (shear component of compressive force)** CTT force accommodated for in normal animal by the CCL (normal passive constrained) -CTT proportional to slope of the tibial plateau, if slope decreases CTT also decreases

Answer 63

Tibial Plateau Leveling Osteotomy TPLO -intend of surgery: attain slope of ~5-7 degrees , the quadriceps muscle group help. -"Pivot shift" is failure to control internal rotation resulting in drawer, outcome following TPLO surgery is uncertain -Preferred for larger active dogs, long-term rehab and postoperative care.

Answer 64

-Based on the same principles of biomechanics than TPLO -Results in change of relative position of the tibia -May result in complication of stifle extensor mechanism -Management of CCLR and increased TPA in young dogs -OPEN PROXIMAL TIBIAL PHYSES, the TWO will not affect phases as can TPLO

Answer 65

-Osteotomy of non-wt-bearing limb portion of the tibia -Patellar ligament is aligned perpendicularly to tangent of femorotibial eliminating cranial tibial thrust -Relieves the function of the CCL -TPLO accomplishes the same redirection of vector at the TTA by rotating tibial plateau to neutralize the tibiofemoral shear force, but it may increase tension -TTA theoretically reduces patellar ligament, has less postoperative patellar ligament inflammation than TPLO, does not affect joint congruency, does INCREASE LOADING of caudal cruciate -TTA places patellar ligament perpendicular to slope of tibial plateau by advancing its insertion in a cranial direction. Eliminates tibiofemoral shear force with weight bearing and relieving the function of the CCL

Answer 66

Cobra: center of rotation and angulation -Applied for angular limb deformity correction in orthopedics -Circular osteotomy in opposite direction to TPLO

Answer 67

Regardless of technique used, Ruptured CCL, -Inspect meniscus by arthrotomy or arthroscopy -Identify tears -Damage to caudal body of medial meniscus seen in 50-75% of patients, most have bucket handle tear, which MUST BE EXCISED 85-90% patients improve DJD progresses regardless of treatment Decline in activity overtime Increasing level of disability Adverse response to cold weather Stiffness after inactivity related to progressive DJD

Answer 68

-Usually associated with trauma, most result from HBC, blunt trauma. -Pathologic reasons: primary metastatic bone tumors Radiographs show -Cortical lysis -New bone formation -Lytic-proliferative lesion PE -Usually non-weight bearing, swelling, pain, crepitus (granting, gritty) -Thoracic auscultation and percussion help detect cardiac or airway abnormalities -Abnormal heart and rhythm, pulse deficits suggest traumatic myocarditis. -Pneumothorax, contusion, diaphragmatic hernia -Assess for pelvic fractures: pelvic girdle symmetry -Rectal palpation to determine presence of pelvic fractures -Careful assessment of Urinary tract if pelvic fractures present Femoral diaphyseal fractures: disrupt continuity of diaphyseal cortical bone Supracondylar fractures: fractures of the distal diaphysis Hit by car are the most common cause Dx -Radiographs -Painful and require sedation or general anesthesia for proper positioning, may be taken prior to surgery but reduce planning ability -Radiographs of contralateral limb: useful in assessing normal length and shape, reference for implant's size DDx -Muscle contusion -CF luxation -Fractures of pelvic girdle -Ligamentous injury to stifle Medical management -Analgesics for post traumatic pain -Antibiotic for open fractures -NOT recommended casts or splints bc adequate stabilization is difficult with these methods Pre-Operative -Stabilize patient -Not usually immobilized bc difficulty in applying coaptation splints -Confined to small area -Analgesics Surgery -Intermedullary pins Normograde placing: cutting pin at level of trochanter. Pin end may injure sciatic nerve. Retrogade placement: hold femur adducted and hip in extension driving IM pin through trochjnteric fossa, may injure sciatic nerve. -Interlocking nails: discussed in first lectures -IM pins plus ESF -ESF alone: External skeletal fixation, challenging surrounding muscle mass and abdomen and motion of stifle. Supply bending, axial and rotational support. -Bones plates used for femoral diaphyseal fractures: ideal for complex or stable fractures when prolonged healing is anticipated. Plate size according to patient size and plate function May serve as compression plate, neutralization plate, bridging plate. +/- IM 1. Dynamic compression plate 2. Limited Contact dynamic compression plate 3. Locking compression plate Complications -Delayed union -Nonunion -Malunion -Osteomyelitis -Pin tract infection -Fixation failure Common errors -Sciatic nerve injury due to improperly placed IM pins -Loosening and migrating of pins and cerclage wire, ESF -Breakage of implants can occur through fatigue. Causes devascularized bone fragments = small fracture gaps unfavorable for healing -Single IM pin used -Destruction of biological environment and delays healing, contributes to implant failure

Answer 69

-Femoral neck fractures: Occur at base of neck where it joins metaphysics of proximal femur -Articular fractures involve joint surface -Epiphyseal and metaphyseal occur in trabecular bone at proximal and distal end of the femur -Angle of femoral neck normally 135 degrees inclination -Normal angle of anteversion is 15-20 degrees : external rotation of proximal femur relative to distal femur. Important consideration when screw or pins are implanted

Answer 70

-Femoral neck fractures: Occur at base of neck where it joins metaphysics of proximal femur -Articular fractures involve joint surface -Epiphyseal and metaphyseal occur in trabecular bone at proximal and distal end of the femur -Angle of femoral neck normally 135 degrees inclination -Normal angle of anteversion is 15-20 degrees : external rotation of proximal femur relative to distal femur. Important consideration when screw or pins are implanted Femoral head and neck fractures -Craniolateral approach to hip -If alignment difficult trochjnteric osteotomy performed -Best stabilize with lag screws or K-wire

Answer 71

Unicondylar fractures done with lag screw bicondylar requires lag crew, Steinmann pins (dynamic cross pinning), or bone plate

Answer 72

-radiographs -Pain management -Activity restricted to leash walking and rehab until fracture is healed Physical Rehabilitation -Optimizes limb function

Answer 73

-Radiographs: Repeat @ 6 weeks intervals until healed -Implants assessment: generally not removed unless there is a problem -Pain management -Activity restricted to leash walking and rehab until fracture is healed Physical Rehabilitation -Optimizes limb function -specially important in stifle involvement fractures Complications -Inappropriate reduction and poor implant choice -Most commonly with femoral head fracture -Significant bending and shear stress placing extreme loads on implants -Most common implant error: use of K-wires or small pins when fracture assessment indicates prolonged healing -Pins loosening early due to micro motion at pin-bone

Answer 74

Most affected <10mts old animals Young males more likely trauma because of tendency to roam. **Young heavy cats male neutered <6mts also at risk** -Capital physical injuries may occur without significant trauma bc femoral physical fracture occurs through cartilage of growth plate -Capital physics functions to provide femoral neck length until ~8mts of age -Distal physis functions to provide most femoral length -In most fractures growth cartilage damaged by traumatic incident, in post traumatic period, or during surgery Physical fractures heal rapidly, most do not continue to function The younger the animal the more traumatic effects of premature closure of injured physis Surgical treatment -Intervention required to prevent DJD and lameness -Anatomic reduction and stabilization with K-wires or small pins that are smooth -Smooth implants generally sufficient -Prevention of movement -With greater trochanter separation: physis must be anatomically reduced and stabilized with tension band, counteract distractive forces of gluteal muscles.

Answer 75

They cause loss of wt-bearing support Plantigrade stance: occurs when foot positioned so plantar surface of calcaneus contacts ground Valgus position: an outward deviation Varus position: an inward deviation **Rare in small animals** **Mostly working breeds** **Fractured calcaneus not rare** -Often disabling bc tarsal joints serve a major wt-bearing function -Without treatment joint incongruity and development of osteoarthritis lead to severe lameness Calcaneal Fractures -Distracted by pull of gastrocnemius muscle. Prevents bone contact between fragments and interferes with healing -Treatment methods must resist tensile force Talar Neck and Condylar Fractures -Occurs in cats and occasionally in dogs -Anatomic reduction and rigid fixation a must -Difficult reconstruction due to small size of trochlea and degree of comminution, arthrodesis when not possible Fractures of the Central Tarsal Bone **Common in racing Greyhounds** **Rarely seen** -Repair with one or more small lag screws -When buttress effect of central tarsal bone lost, fractures of 4th tarsal and calcaneus occur. **Buttress = support** PE findings, Central tarsal bone -Non-wt-bearing lameness -Attempts to place wt on limb cause tarsus to collapse in plantigrade stance PE findings , Calcaneus -May walk plantigrade on limb -May be non-wt bearing -Pain, swelling, heat, crepitus present -Varus or valgus deviation usually present Diagnostic imaging -Require sedation -Dorsoplantar, medial-lateral, and oblique usually sufficient to make diagnosis DDx -Calcaneal fractures differentiated from lacerations or rapture of Achilles tendon. -Acute lacerations to achilles tendon: open wound and soft tissue swelling around area proximal to calcaneal tuberosity. -Fractures of calcaneus: swelling caudal to tarsus and crepitation elicited on palpation. **Medical/conservative management not indicated** Surgical Tx -Calcaneal: pull gastrocnemius m. tension, wire, lag screws or plate. -Talar fractures: anatomically reduced and rigidly stabilized for optimal outcome. -If fracture repair not feasible, arthrodesis of tarsocrural joint considered Pre-surgery -Stabilized, examined for concurrent injury -Check for open wounds: clean, protect from further contamination. -Mason metasplint or bivalve cast applied for comfort and protect soft tissue from further contamination or injury by bone fragments. -Analgesics provided to post traumatic animals. Surgical Anatomy -Calcaneus is the largest of the tarsal bones: has two distal facets and processes that articulate with talus -Tuber calcaneus forms sturdy prominence to accommodate INSERTION OF THE ACHILLES TENDON -Talus: second largest: articulates with tibia and fibula and distally with central tarsal bone. Medial and lateral trochlea (articulate with tibia and fibula). Sides of trochlea articulate with medial and lateral malleoli

Answer 76

-Transverse fractures: tension band wire or plate -Oblique fractures: lag screws -Articular surface: diverging Kirschner or lag screws

Answer 77

Large screw, angled from caudal medial surface of head of talus into trochlea, from there into calcaneus

Answer 78

-Radiographs to evaluate fracture reduction and implant location -Pain management -Coaptation with a soft padded bandage controls bleeding and swelling -Coaptation with splint up to 6 weeks -Activity restricted to leash walking and PT until healed -Passive flexion and extension of tarsus -Pins used in application of tension band for stabilization of calcaneal fractures may irritate soft tissue. REMOVE after healing if needed -Screws NOT removed Complications -Articular fractures degenerative joint disease -Delayed union and nonunion if not adequately calcaneal stabilization, gastrocnemius muscle pull/tension. Prognosis -Calcaneal: excellent to return to normal -Tarsal: fair to good, depends on degree of articular cartilage damage and reconstruction needs.

Answer 79

Metatarsal bone fractures -Common in dogs and cats -Result direct blow to paw or hyperextension injuries **Greyhounds: result from fatigue, loaded beyond its yield strength** -Classified based on location: Base, proximal end, shafts, or diaphysis, head or distal bone Early surgical repair -Better results than closed reduction and splintage -Chronic instability leads to DJD and less than optimal function -But DEPENDS, splinting may be appropriate Avulsion fractures of base occur most often on 2nd and 5th bones -Due to their ligamentous insertions Phalangeal fractures occur similarly in dogs and cats: fragments often smaller and more difficult to secure.

Answer 80

-Mostly working dogs or racing Greyhounds -Early surgical repair better results -Chronic instability leads to DJD and les optimal function Diagnostic imaging -Dorsoplantar and mediolateral views from tarsus to end of digits -Oblique views with digits spread -A lateral view affected digit pulled cranially with tape or gauze -Stress radiographs may need to displace distal digit to show joint instability Medical management -Analgesics for postraumatic pain -Conservative tx with fiberglass bivalve cast or metasplint: used for nondisplaced metatarsal diaphyseal fractures of 1 or 2 bones **especially 2nd and 5th digits** Non-wt-bearing -Coaptation (joining or reuniting two surfaces): cats with comminuted non reducible features. -Most phalangeal fractures and acute sesamoid bone fractures -Cast or splints not removed until radiographic evidence that fracture bridged w/bone, usually 4-8 weeks. Surgical Treatment -Metatarsal fractures in athletic or racing dogs: require anatomic reduction and rigid stabilization, plates and screws -Plate fixation: when FAS is low or when athletic function is desired Bridging plate: digit 2, span and support comminuted Compression plate: for transverse fractures, digit 3-4 Lag screw: Digit 5, oblique fracture, neutralizing plate. -Large avulsed (An avulsion fracture occurs when a small chunk of bone attached to a tendon or ligament gets pulled away from the main part of the bone) fragments from base of 2nd and 5th metatarsals: require open reduction generally and internal fixation -Lag screws: used to counteract pull of adjacent ligament or compress oblique fractures.

Answer 81

1 & 2 bones: splint or cast 3 & 4 bones: internal fixation Large displaced avulsion fractures with lag screws **Splint or bivalve cast applied after internal fixation until radiographic evidence of bone healing achieved** same for metacarpal Intramedullary (IM) Pinning Technique -Multiple transverse or short oblique fractures with high FAS patients -Slot in distal metaphysics, pin through slot, drive proximally Fractures of phalanges are less frequent, most amenable to splinting

Answer 82

Acute phalangeal laxations in working or racing dogs: open reduction and suturing of joint capsule, lateral collateral ligaments. Chronic laxations of 2nd and 5th toe treated with amputation Arthrodesis of metatarsophalangeal and interphalangeal joints result in good function and pain relief Surgical Treatment -Orthopedic wire -IM pins -External fixation -Plates and screws External Fixation of Metatarsal Fractures -Connect fixation pins with acrylic bars: provides rigid stabilization of comminuted fractures -Fixation does not interfere with open wound treatment -OR place pins type Ib configuration and connect with acrylic Phalangeal Fractures and Luxations -Handled same as for the forelimb -Digit masses: amputate same as for the forelimb -Digit amputation: performed same as for the forelimb

Answer 83

Paucity (the presence of something only in small or insufficient quantities or amounts; scarcity) of soft tissue increases potential for open fractures, decrease of extra osseous blood supply. Both can delay bone healing. Paucity advantageous for placing ESF (external skeletal fixators), but Tissue irritation, cold hypersensitivity -Mostly trauma fractures, entire animal needs to be evaluated for concurrent injuries. Rib fractures, pneumothorax, pulmonary contusions, traumatic myocarditis, may include extensive soft tissue damage or loss. Diagnosis -Signalment: any age, breed, cat or dog. -history: non-wt-bearing lameness of affected limb PE -Crepitation and pain, palpable swelling, -Often appear to have abnormal propioceptive response bc they are reluctant to move limb. -Requires sedation for radiographs, painful. -Radiographs of contralateral limb useful, used to contour bone plate more precisely, approx size of implants, compare bone light and shape. -Evaluate for neoplasia or metabolic disease if trauma not definitive Dx. Medical management -Analgesics, antibiotics for open fractures. Conservative: splints and casts for closed, non displaced or greenstick in immature animals (A greenstick fracture occurs when a bone bends and cracks, instead of breaking completely into separate pieces. The fracture looks similar to what happens when you try to break a small, "green" branch on a tree). -Cast/splint fixation appropriate bc joint above and below (stifle and hock) can be immobilized. Should heal quickly Surgical treatment -Decision to perform open or closed reduction based on: 1. Fracture configuration 2. Fracture assessment score 3. Implant selected -Open reduction: autogenous cancellous bone indicated (sites for harvest: Ipsilateral proximal humerus, wing of the ilium, ipsilateral distal femur) -Fixation systems include: Casts, IM pins with cerclage wire or ESF support, interlocking nails, ESF (linear, circular, hybrid). Bone plates Preoperative -Open wounds management: swabs for bacterial culture and susceptibility testing -Culture results before antibiotics administration -ROBERT JONES bandage temporary stabilization -Decrease swelling, protect and enhances comfort until surgery -Analgesics, anesthesia for fracture fixation, prophylactic antibiotics. Positioning -leg prepared from hip to below hock -Donor site prepared, if using harvested cancellous bone -Closed reduction or limited open reduction: leg suspended from ceiling. -Open reduction and plate application: can also be performed with leg suspended. If IM pin or interlocking nail application = dorsal recumbency and limb draped out and released to expose medial surface External Coaptation -FAS 8-10: full cylinder cast, immobilizes stifle and hock, limb in extension with slight virus angulation. Cast bivalve: apply over multiple layers of padding, cutting lateral and medial aspects. Secure with elastic tape. Application of IM pins -Tibial diaphyseal fractures: excellent resistance to bending, additional implants for axial and rotational support. - Transverse or short oblique, requires ESF splint to control rotation. **Length of fracture line is 2-3 times diaphyseal diameter** -Multiple cerclage wires

Answer 84

Paucity (the presence of something only in small or insufficient quantities or amounts; scarcity) of soft tissue increases potential for open fractures, decrease of extra osseous blood supply. Both can delay bone healing. Paucity advantageous for placing ESF (external skeletal fixators), but Tissue irritation, cold hypersensitivity -Mostly trauma fractures, entire animal needs to be evaluated for concurrent injuries. Rib fractures, pneumothorax, pulmonary contusions, traumatic myocarditis, may include extensive soft tissue damage or loss. Diagnosis -Signalment: any age, breed, cat or dog. -history: non-wt-bearing lameness of affected limb PE -Crepitation and pain, palpable swelling, -Often appear to have abnormal propioceptive response bc they are reluctant to move limb. -Requires sedation for radiographs, painful. -Radiographs of contralateral limb useful, used to contour bone plate more precisely, approx size of implants, compare bone light and shape. -Evaluate for neoplasia or metabolic disease if trauma not definitive Dx. Medical management -Analgesics, antibiotics for open fractures. Conservative: splints and casts for closed, non displaced or greenstick in immature animals (A greenstick fracture occurs when a bone bends and cracks, instead of breaking completely into separate pieces. The fracture looks similar to what happens when you try to break a small, "green" branch on a tree). -Cast/splint fixation appropriate bc joint above and below (stifle and hock) can be immobilized. Should heal quickly Surgical treatment -Decision to perform open or closed reduction based on: 1. Fracture configuration 2. Fracture assessment score 3. Implant selected -Open reduction: autogenous cancellous bone indicated (sites for harvest: Ipsilateral proximal humerus, wing of the ilium, ipsilateral distal femur) -Fixation systems include: Casts, IM pins with cerclage wire or ESF support, interlocking nails, ESF (linear, circular, hybrid). Bone plates Preoperative -Open wounds management: swabs for bacterial culture and susceptibility testing -Culture results before antibiotics administration -ROBERT JONES bandage temporary stabilization -Decrease swelling, protect and enhances comfort until surgery -Analgesics, anesthesia for fracture fixation, prophylactic antibiotics. Positioning -leg prepared from hip to below hock -Donor site prepared, if using harvested cancellous bone -Closed reduction or limited open reduction: leg suspended from ceiling. -Open reduction and plate application: can also be performed with leg suspended. If IM pin or interlocking nail application = dorsal recumbency and limb draped out and released to expose medial surface External Coaptation -FAS 8-10: full cylinder cast, immobilizes stifle and hock, limb in extension with slight virus angulation. Cast bivalve: apply over multiple layers of padding, cutting lateral and medial aspects. Secure with elastic tape. Application of IM pins -Tibial diaphyseal fractures: excellent resistance to bending, additional implants for axial and rotational support. - Transverse or short oblique, requires ESF splint to control rotation. **Length of fracture line is 2-3 times diaphyseal diameter** -Multiple cerclage wires -Avoid interference with stifle, retrograde pinning may damage intra-articular structures in dogs and patellar ligaments in cats. -NORMOGRADE a must -Pin inserted through skin on medial aspect of proximal tibia

Answer 85

Type Ia: on craniomedial surface of tibia to stabilize transverse fracture. Type Ib: anatomic reconstruction with cerclage wire, restores bony column and allows load sharing with type Ib ESF Type II: minimal type II constructed with unilateral fixation pins, LOW FAS

Answer 86

Compression plate: transverse fractures Neutralization plate: support long oblique fractures with lag screws

Answer 87

Failure to reproduce normal cure of tibia = valgus or varus angulation of the limb.

Answer 88

-Osteomylitis -Implant migration -Malunion -Delayed union -Non-union -Pin loosening and drainage **Poor implant choice most common reason for complications** -Cats treated with rigid ESF may be at risk for delayed healing or non-union Prognosis -Generally good

Answer 89

-Occur infrequently in mature dogs and cats Proximal metaphysics and epiphysis -Transverse oblique or short oblique usually, may be comminuted severe trauma, gun shot Distal metaphysics and epiphysis in mature animals -Usually involves malleoli and erosion injuries that remove malleoli, from loss of collateral ligament function and talocrural instability. -Accurate alignment of articular surface of malleolar fractures and rigid fixation needed to achieve joint stability and minimize development of DJD Surgical Treatment -High FAS, IM pin, K-wire and figure 8 wire added for rotational stability. Crossed K-wires may be used -Malleoli repair: Lag wire screws, tension band wires high FAS Prognosis next slide

Answer 90

Metaphyseal fractures usually heal quickly due to large amounts of cancellous bone surrounding the fracture In general tubercular bone heals with minimal formation of callus Physeal fractures occur through cartilaginous growth plate in immature animals = slipped physes: weaker than surrounding tissue bone and ligaments, more susceptible to injury and may or may not be displaced. Salter Harris classification on basis of radiographs and histologic appearance Salter Harris I and II with concurrent fracture of fibula: epiphysis may be displaced cuadolateral to tibial diaphysis, collateral ligament injury may occur. -Open reduction and internal fixation: restore normal anatomy so required. -Compare to radiographs of opposite limb, particularly with tibial tuberosity avulsions. Radiographs taken at time of injury NOT much information about damage to blood supply -Difficult to give an accurate prognosis for growth -FAS 8-10 most common, need surgical treatment. young animals heal quickly and mostly affected. Implants need to function for a long time -K-wires or small pins plus anatomical reduction, use smooth pins so it doesn't interfere with physical function, perpendicular to physics.

Answer 91

Excellent for healing Growth function depend on amount of damage, good if zone of hypertrophied cells is separated at cartilaginous physis Most trauma-induced physical fractures sustain damage to growing cells and have a guarded prognosis for growth Caudal malalignment of proximal tibial epiphysis may result in increase tibial plateau angle Premature closure of tibial tuberosity physis can alter conformation of proximal tibia, results in impaired function and stifle DJD.

Answer 92

-Scapulohumeral Joint Luxation -Shoulder Instability -Biceps (brachii) Tendon Disease -Supraspinatus Tendinopathy

Answer 93

When loss of damage of supporting structures of joint cause separation of the humerus from scapula. The supporting structures include: joint capsule, glenohumeral ligaments and surrounding tendons. Significant structures include: teres major, teres minor, and subscapularis mm. zz Same as dislocated shoulder or shoulder luxation Causes: trauma or congenital

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