Ch 52 Elbow disease Flashcards

Question

lateral approach to the proximal end of the radius

Answer 1

Lateral rotation/luxation of the ulna affects predominantly small purebred dogs deformity is typically noted at birth or soon thereafter anconeal process and the medial coronoid process are variably present Conservative treatment may be considered for patients with good function and no pain. However, early reduction and stabilization of the joint are generally indicated Closed Reduction and Immobilization younger than age 4 months recurrence is prevented by placement of a transarticular pin or a modified ESF one or two small threaded K wires from caudal to cranial through the trochlear notch into the distal end of the humerus. removal 14 to 21 days later caudolateral approach to the elbow transposition of the olecranon medially and distally, ulnar osteotomy and radioulnar synostosis, trochlea and trochlear notch reconstruction, external fixation, and transarticular pins

Answer 2

syndrome that includes several developmental abnormalities, leading to osteoarthritis, pain, and disability Include - fragmented medial coronoid process (FCP), - osteochondrosis (OC[D]) of the humeral trochlea - ununited anconeal process - articular cartilage damage - joint incongruity. inherited condition, incidence of 0% to 55%, depending on breed, population, and screening technique young large- and giant-breed dogs, abnormality of the MCP + incongruity have been recognized in smaller (chondrodystrophic) breeds as well

Answer 3

- fragmented medial coronoid process (>96% of developmental elbow disease cases) - osteochondrosis (2.7% to 25.4% > 25.4% of Golden Retrievers) - incongruity (6.0% to 50.3% > 50.3% of Bernese Mountain Dogs) medial coronoid process, osteochondritis dissecans of the trochlea, and elbow joint incongruity are often concurrent and affect the medial compartment of the elbow joint.

Answer 4

1. provides stability by limiting mediolateral movement when engaging the humerus. 2. While weight bearing, it is the primary stabilizer of the elbow joint in pronation and a secondary stabilizer in supination

Answer 5

Bernese Mt Dogs and Mastiffs 13 - 30% have concurrenct FMCP Bilateral in 20 - 35% male dogs twice as frequently as female radioulnar incongruence reported in 50% to 100% of cases often present btw 5 and 12 months German Shepherd Dog, Golden Retriever, Labrador Retriever, Newfoundland, Rottweiler, Saint Bernard Dog, Great Dane, French Bulldog, Dachshund, and Weimaraner.

Answer 6

14-15wk in Greyhounds 16-20wk GSD

Answer 7

Positive: Ulna longer than the radius Negeative: Radius longer than ulna

Answer 8

- radioulnar incongruity - large-breed dogs have a secondary center of ossification of the anconeal process - develops by appositional ossification, formation of a separate ossification center, or both - STUDY: secondary center of ossification (SCO) was radiographically apparent in 16% of dogs> different to UAP. - presence of SCO does not result in UAP, earlier diagnosis should be possible due to the radiographic difference - etiology unclear; proposed theories: metabolic genetic failed endochondral ossification, repetitive growth plate trauma associated with rapid growth underdevelopment of trochlear notch incongruous growth between the radius and the ulna (proximal displacement radial head > pressure on anconeal process) - polygenic mode of inheritance - instability caused by loss of the stabilizing function - free or attached via fibrous tissue or fibrocartilage

Answer 9

1. Damage to the distal ulnar physis, ulna becomes shorter than the radius> decreasing the distance between AP and radius> humeral condyle shifts proximally> excessive force on the developing anconeal process. Repeated microtrauma > damage the center of ossification supported by clinical reports of fusion from PUO 2. reduction in the vertical distance between AP and the radial incisure (decreased trochlear notch size) > poor articulation between the ulna and humeral condyle > increase loading AP thus preventing union

Answer 10

RADs maximally flexed mediolateral radiograph > UAP dx (minimizes superimposition) area of lucency (cleavage plane) is apparent osteophyte production, joint distention, muscle atrophy, and irregular subchondral sclerosis both elbows should be obtained radiographic diagnosis traditionally not made until at least 20 weeks CT or arthroscopy diagnosis of concurrent dz size and shape of the fragment, from which the likelihood of successful fixation

Answer 11

Early intervention is recommended to optimize reviewing studies : radiographic healing of the anconeal process is inconsistently defined + objective evaluation of function following surgical procedures is warranted

Answer 12

caudolateral approach, midbelly incision anconeus muscle. The fragment is grasped Although owners appeared satisfied with the surgical outcome, only 50% of dogs were free of lameness warned of the progression of osteoarthritis Consider removal > malformed anconeal process or severe OA

Answer 13

dogs < 24 weeks of age screws in lag fashion +/- K wires from the articular surface> olecranon or caudal olecranon > anconeal process Exact positioning is important, risk of implant failure STUDY: Union obtained 2 to 6 months after surgery in 6 of 10 dogs retrospectively theory of radioulnar incongruity > reattaching AP without PUO may increase the risk of implant failure

Answer 14

rationale: contraction of the triceps brachii muscle to pull the ulna proximally during weight bearing. This proximal migration> expected to restore the normal alignment of joint surfaces + alleviating the biomechanical loads on the AP by the humerus. encourage union between the anconeal process and the ulna proximal better than distal re facilitate proximal migration of the ulna > may be associated with higher morbidity (interosseous ligament prevents migration) caudal tipping and varus deviation minimized by oblique plane or IM pin complication > migration of IM pin successful in dogs < 7 months and with a firmly attached and nondisplaced AP STUDY: 15/21 healed, 17 good to excellent clinical outcome. Results were less favorable in another study 5 of 23 achieved union | limited caudal approach to the ulna

Answer 15

sole ulnar osteotomy or reattachment AP does not produce consistently acceptable outcomes > therefore both total of 58 elbows has been reported in the literature, with an overall fusion rate of 93%. One of these studies was a retrospective multicenter analysis comparing the outcomes of two surgical >significantly better radiographic outcome than those that had only an ulnar osteotomy

Answer 16

- Anconeal process removal (owners satisfied but only 50% free of lameness) - Reattachment (dogs under 24 weeks with normal trochlear notch, 60% fusion 2-6m) - Ulnar osteotomy/ostectomy - Reattachment and ulnar osteotomy/ostectomy (fusion 93%)

Answer 17

Most successful in dogs under 7m with firmly attached, non-displaced anconeal process Located 3-6cm distal to articular surface Proximocaudolateral to distocraniomedial at 40-50 degrees to long axis +/- IM pin

Answer 18

Labradors, GSD, English Setter term flexor enthesopathy proposed to summarise pathological changes within the flexor muscles of the carpus and digits and their attachments to the medial epicondyle, without referring to any suspected, but still unknown, etiology (i.e osseous metaplasia, ununited medial humeral epicondyle etc)

Answer 19

Extending the carpus while holding the elbow at 90 degrees Rads partial avulsion of the tendons, discreet enthesophyte on the medial aspect of the distal part of the humeral diaphysis (just proximal to the medial epicondyle) and large ossified bodies Arthroscopy allows for evaluation of the tendinous muscle attachment from within the joint capsule,

Answer 20

Conservative Intra-articular methylpred Tenotomy Partial excision Resection of osseous bodies Prognosis is generally good with the primary form (i.e without intra-articular lesions and osteoarthritis)

Answer 21

medial coronoid process disease medial coronoid sclerosis, coronoid microfracture, coronoid fragmentation or fissuring, and cartilage damage to the coronoid process medial compartment disease advanced” or “end-stage” in elbows with extensive damage to or loss of joint cartilage within the medial joint compartment Cartilage lesions within the medial compartment include: OCD abrasion from humeroulnar conflict i.e., “kissing lesions” joint incongruity

Answer 22

young, large- to giant-breed dogs. Males twice as frequently OCD + MCPD share similar breed predisposition in Labrador Retrievers, German Shepherd Dogs, and Rottweilers incongruity is seen primarily in lab, GSD, Rotti, bernese affecting 60% of elbows with medial coronoid process disease elbow joint incongruity > chondrodystrophic breeds OCD present between 5 and 8 months, medial coronoid process disease is 13 months bilateral disease has been reported as anywhere from 25% to 80% of dogs distinct biphasic pattern, with peaks at ≤3 years and ≥7 years incidence of multiple components varies > anywhere from 0 to 60%

Answer 23

screening programs still based on the radiographic appearance of elbows, rather than on genetic screening, because the genes involved remain unidentified osteochondritis dissecans, medial coronoid process disease, and elbow joint incongruity appear to be inherited independently as polygenic traits complexity of inheritance and the effect of environmental variables in disease expression complexity also affects breeding programs focusing on phenotypic selection phenotypic selection results in the exclusion of at most 18% of the highest risk animals from breeding. Estimated breeding values have been shown to be more reliable than phenotype

Answer 24

Micro-CT evaluation of coronoid processes at 5, 7, 9, and 12 weeks of age clearly proved the absence of a secondary ossification center STUDY: no evidence of osteochondrosis on histomorphometric analysis of MCP in 38 dogs, instead, microcracks were noted in the trabecular bone > indicate that fatigue microdamage of the underlying subchondral bone plays a crucial role in the pathogenesis (consequence of excessive loading of this area) Microdamage and loss of osteocytes and canalicular density was greatest in the radial incisure region structural changes within the subchondral bone precede articular cartilage fissure/fracture STUDY: Prospective and, in part, serial evaluation of medial coronoid processes of growing Labrador Retriever puppies,186-189 with or without developmental elbow disease, using radiography, CT, necropsy examination, micro-CT, and histology revealed that medial coronoid process disease begins at approximately 15 weeks of age and that it involves only subchondral bone > By 15 weeks of age, localized disturbance of endochondral ossification, leaving weak points that may develop into cracks between the retained cartilage and the subchondral bone

Answer 25

the etiopathogenesis is not fully known Earlier microscopic studies suggested that a delay in endochondral ossification may play a role in MCD development in labs, though recent studies have focused more on biomechanical forces acting on the medial coronoid process during maturation that are thought to initiate cleft formation, fracture, bone remodeling, and, ultimately, fatigue of the subchondral bone of medial coronoid process. \ Overloading of the medial compartment of the canine elbow joint may result from different forms of joint incongruence. Several theories have been suggested, the most pervasive are those of radioulna incongruity and humeroulnar conflict. 1. traditional linear model of RUI (short radius, positive RUI) leads to redistribution of load-bearing forces (mainly axial) from the radial head to the medial coronoid process, leading to tip fissure/fracture. coexistence of UAP and MCPD in the same joint challenges the linear model 2. angular vector model (short ulna, negative RUI) the radius (longer than the ulna) would cause an inclination of the humeral condylar axis to cause an increase in the load at the level of the medial humeral condyle and the medial coronoid process of the ulna (torsional moment on radius, pivot on anconeal process to bring medial portion of humeral condyle into contact with apex of MCP). 3. radial incisure fissure/fracture may be due to torsional overload of radial head (rotational RUI). Supraphysiological loading of the lateral aspect, along the radioulnar joint, postulated to be mechanical cause. Load-induced pronation → pressure of radial head on MCP. Micro-CT findings: some torsional force component in fragment development, torque moment could result from soft tissue laxity in the lateral aspect excessive pull of the biceps brachii/brachialis muscle (fitzpatrick) 5. Dynamic axial RUI of icreased load during weightbearing was been refuted by studies showing adult dogs without elbow disease, activity results in dynamic axial translation. In fact, in MCPD affect joints, static RUI was pervasive during walk rather than any dynamic change occuring (rohwedder) differences in the motion pattern between healthy joints and elbows with medial coronoid disease could be detected > fluoroscopic kinematography 5. Osseous conformational discrepancy/ ligamentous insufficiency, relative humeroulnar rotational instability, moment forces the trochlea against MCP, probably resulting in repetitive, chronic mechanical overload Regardless of the type of incongruity, the consequence is a maldistribution of the load forces, which are mainly directed toward the medial coronoid process of the ulna

Answer 26

.1. insufficient growth of the trochlear notch, leading to a slightly elliptical notch that is too small to accommodate the humeral trochlea, Unproven to be present .2. Radioulnar incongruity (RUI) - static axial radioulnar incongruence (short radius) leads to redistribution of load-bearing forces from the radial head to the medial coronoid process dt creates a step at the level of the radial incisure and proximal displacement of the entire coronoid process - localised positive RUI at apex: tip deformation, (dt Abnormal development). rejected: authors concluded that subchondral bone surface geometry does not relate to medial coronoid process disease (normal anatomical variation) - traditional linear model: Positive RUI = short radius → pressure on MCP or Negative RUI = short ulna → pressure on AP. The documented coexistence of ununited anconeal process and medial coronoid process disease in the same joint challenges the linear model - Angular vector model Positive RUI = short radius → pressure on MCP Negative RUI = short ulna → pressure on MCP and AP: hort ulna) is believed to increase intraarticular pressure within the medial joint compartment by applying force against the lateral aspect of the humeral condyle. while CT restrospective STUDY documents negative RUI > Experimental evidence is lacking. axial radioulnar incongruence, is thought to develop as a consequence of asynchronous growth between the bones etiologic relationship between the initiation of medial coronoid process disease and radioulnar incongruence has been disproved by prospective monitoring of the development > puppies that later proved to have medial coronoid process disease showed normal skeletal development similar to the seven sound control dogs: but probably related to course and severity of disease later on .3. Dynamic axial RUI Same scenarios as with static RUI, but being dependent on deformation of the radioulnar joint cup during weight-bearing activity (dt elasticity in the interosseous membrane in young) but adult dogs without elbow disease, activity results in dynamic axial translation .4. Rotational RUI Supraphysiological loading of the lateral aspect, along the radioulnar joint, postulated to be mechanical cause of radial incisure fracture/fissure pattern - Load-induced pronation → pressure of radial head on MCP - Mismatch between curvature of the radial head and MCP → radioulnar conflict - Increased biceps brachii and brachialis muscle pull → pressure of MCP on radial head Micro-CT findings: some torsional force component in fragment development, torque moment could result from soft tissue laxity in the lateral aspect excessive pull of the biceps brachii/brachialis muscle > eccentrically located position (medial to the joint), a substantial portion of the flexion forces would be expected to cause supination, thereby creating shear .5. Varus-instability of the humeroradioulnar joint Osseous conformational discrepancy/ ligamentous insufficiency> allow for angulation of the humeroulnar joint surfaces (varus deformation) Varus-instability → compression of MCP between humeral trochlea and radial head .6. Dynamic axial humeroulnar joint instability Osseous conformational discrepancy/ ligamentous insufficiency, relative humeroulnar rotational instability, moment forces the trochlea against MCP, probably resulting in repetitive, chronic mechanical overload STUDY: kinematics in sound dogs and MCPD, In vivo humeroulnar contact patterns support this assumption of mechanical overload at the lateral border

Answer 27

Labs, GSD, Rottweilers 60% concurrent incongruity Bilateral 25 - 80%

Answer 28

Subchondral defects 15 weeks Articular cartilage defects 18 weeks Glycosaminoglycan content depletion of the articular cartilgae parallels the subchondrl bone defects.

Answer 29

Positive (short radius) - 45% Negative (short ulna) - 14%

Answer 30

MOS 1: Cartilage softening anf swelling MOS 2: Partial thickness surface defects, fibrillation MOS 3: Deep fibrillation to subchondral bone MOS 4: Full thickeness cartilage erosion MOS 5: Subchondral bone eburnation

Answer 31

MOS + MCP changes + humerus changes

Answer 32

Traumatic fracture of the medial coronoid process without preexisting developmental abnormality

Answer 33

1. part of osteochondrosis/osteochondritis dissecans of the humeral trochlea 2. Result from humeroulnar conflict and/or medial coronoid process disease. The term kissing lesion Extension of cartilage erosion around the fragment to the apex and body of the medial coronoid process supports the theory of mechanical conflict Probing lesions during arthroscopic evaluation + MOS recommended cartilage erosions of MCP + opposing trochlea correlate with each other and also with RUI Cartilage erosions have been reported in the absence of fragmentation > probably from DJD secondary to alterations in joint loading

Answer 34

A normal cartilage-free area of the lateral aspect of the trochlea notch, approx half way between tip and radial incisure

Answer 35

- individual components of developmental elbow disease share common clinical signs - Lameness is occasionally difficult to recognize dt bilateral disease - dogs with MCPD occasionally stand with the elbow slightly abducted (voluntary unloading of the cranial aspect) - Pain elicited with palpation of the medial compartment, especially near the tendon of the biceps brachii - Flexion of joint and supination of the limb distal to the elbow joint> compression of the medial joint compartment > elicit pain - Joint effusion caudolateral aspect - Decreased range of motion and crepitus, muscle atrophy - exacerbation of clinical signs with exercise | exclude shoulder

Answer 36

- craniocaudal (OA, OCD, FMCP) - 90 degrees mediolateral (inconguirity) - flexed mediolateral projections (UAP) Radiographic evaluation for medial coronoid process disease is directed at excluding other lesions dt low sensitivity Suggestive of MCPD (sn 80% sp 100%): - Trochlea notch sclerosis - blurring cranial margin of the medial coronoid process Fitzpatrick et al: 13 of 437 (3%) elbows, considered to be free of any radiographic evidence later arthroscopic dx of MCPD high incidence of false-negative radiographic diagnoses (specificity, 10% to 69% CT or arthroscopy is highly recommended in dogs with lameness localized to the elbow joint opacity at proximal aspect of the anconeal process can be incorrectly interpreted as a mild form of osteophytosis appreciation of subtrochlear sclerosis may be rather subjective width of sclerosis on mediolateral radiographs: sensitive predictors of MCPD (91% to 93%) although juvenile elbow screening may reveal radiographic changes in dogs with developmental elbow disease, negative findings **do not necessarily rule out** medial coronoid process disease

Answer 37

- proximal surface of the anconeal process, - cranial aspect of the radial head, - cranial edge of the medial coronoid process, - caudal surface of the lateral supracondylar crest, - medial contour of the humeral trochlea, - medial contour of the medial coronoid process

Answer 38

0 = Normal elbows 1 = Mild: osteophytes less than 2mm high, subtrochlear sclerosis but trabecular pattern still visible 2 = Moderate: Osteophytes 2-5mm high, obvious subtrochlear sclerosis (no trabecular pattern). RU step 3-5mm, indirect signs of primary lesion 3 =Severe: Osteophytes over 5mm high, RU step over 5mm, obvious primary lesion

Answer 39

**DMPLO-35 degrees** diagnostic accuracy of plain radiography for the detection of medial coronoid process disease is lower than that with CT imaging

Answer 40

Radiographs are the mainstay for the diagnosis of osteochondrosis of humeral - flattening or indentation of the subchondral bone contour - sclerosis of the condyle - roughening of the medial epicondylar surface - osteophyte

Answer 41

correct quantification or grading is unreliable for Radioulnar incongruity effect of radiographic positioning on the interpretation of elbow joint congruity: 90 degree flexed lateral - Sensitivity 100% and specificity 70-90% another study: identify congruent elbow joints (specificity) in only 86% and incongruent elbow joints (sensitivity) in only 78% generally accepted that only severe (≥2 mm) radioulnar step formation could be accurately detected by plain radiograph Humeroulnar incongruity has been evaluated using an index of subluxation | accuracy MRI (95.5%) compared favorably to rads (77.2%)

Answer 42

90 degree flexed lateral - Sensitivity 100% and specificity 70-90% for incongruity over 2mm

Answer 43

Dx of MCPD and joint incongruity require advanced imaging limitations of CT is the lack of standardization - small increments (≤1 mm slices), and 50% overlap - Variation in positioning requires cautious comparison between studies - supination and pronation affect joint congruity - dorsal recumbency with the elbow joints extended to approximately 135 degrees sensitivity of CT (71%) was less than previously reported (88.2%). The lower sensitivity: may reflect an improvement by arthroscopic dx Changes consistent: - abnormal shape and sclerosis of MCP, - irregularity of the radial incisure, - fissure or fragmentation of MCP, - lucencies along the radial incisure, - osteophyte formation advantage of CT over arthroscopy: - assess the subchondral bone (sclerosis, necrosis, cysts, fissure, and fragmentation) - disadvantage of CT is the inability to image cartilage lesions | sedation and both elbows at once

Answer 44

29% - Cannot assess the articular cartilage

Answer 45

- Type 1: Round - Type 2: Pointed - Type 3: Flattened - Type 4: Irregular Type 1 most common in normal elbows Type 4 indicative of FMCP

Answer 46

elbow joint incongruity remains the most challenging diagnostic - CT has limited specificity - evaluated on reformatted dorsal and sagittal multiplanar reconstructions either by directly measuring the radioulnar step or by measuring subchondral joint space (dx radioulnar step and widened joint spaces) - Reliably defining the image planes a problem with most tehcniques - create a distinct sagittal multiplanar reconstruction via a duplicated circle superimposition technique (inter- and intraobserver reliability are almost perfect) - sphere-fitting technique have been reported to be sn 94% and sp 89% (most accurate methodology)> complexity imits its broad clinical application

Answer 47

**MRI** - ability to evaluate the articular surface, rather than subchondral bone shape, is a clear advantage of MRI over radiographs and CT - Periarticular soft tissues, however, are best visualized **us** noninvasive and cost-effective approach to early diagnosis of fragmentation of the medial coronoid process At least one ultrasonographic lesion was detected in 13 out of 15 elbows. - effusion (10/15 elbows) - abnormal shape of the medial coronoid process (9/15). Nuclear scintigraphy, PET

Answer 48

unparalleled visibility of joint surfaces and allows simultaneous minimally invasive tx structures seen: - humeral trochlea, - medial collateral ligament, - medial coronoid process, - radial head, - humeral capitulum, - lateral coronoid process, - trochlear notch, - anconeal process - synovial membranes A 1.9 mm short 30 degree oblique arthroscope is therefore preferred Use of a graduated right-angled probe facilitates the evaluation of radioulnar congruity > Factors such as elbow joint flexion angle, pronation and supination, loading condition of the joint, and the presence of the arthroscope in the medial joint space influence radioulnar incongruity Griffon et al demonstrated that there is poor correlation between radiography, CT, and arthroscopy with respect to the degree of incongruity

Answer 49

Abduction and pronation Fluid pump set to 70mmHg (50-100) with rate of 1-1.4L/min

Answer 50

Elbow joint in a neutral position at a standing angle of approx 135 degrees

Answer 51

- Infection 0.2% - Major complication needing additional surgery 4.8% - Conversion to open arthrotomy 5% - Iatrogenic superficial cartilage injury 15% - iatrogenic damage to the ulnar nerve - breakage of a surgical instrument (magnetic retriever and large forceps) - free osteochondral fragment migrates out of the arthroscopic field

Answer 52

- symptom-oriented treatments, which include surgical and nonsurgical treatment modalities, - disease-modifying treatments, directed at correcting the suspected underlying cause several factors should be considered i.e. severity of preexisting OA, the age best prognosis: early surgical treatment in young dogs with minimal to mild osteoarthritis + postoperative rehabilitation + OA modifying tx. objective data regarding the outcomes of specific surgical procedures are lacking, and there are few studies directly comparing different treatment modalities. In the absence of prospective clinical studies > tx a matter of opinion and therefore of controversy

Answer 53

avoid the median nerve, as the flexor carpi radialis and pronator teres muscles are bluntly separated to expose the joint capsule

Answer 54

Osteotomy of medial epicondyle tenotomy of pronator teres

Answer 55

advantages of arthroscopy - reduction in patient morbidity, - ease of treatment of both in a single session, - improved visibility of intra-articular structures, - use of a minimally invasive approach. Disadvantages of arthroscopy - cost of the equipment; - learning curve - fluid extravasation - iatrogenic trauma to the cartilage; - median or ulnar nerve palsy; - diminished visibility in the presence of hemorrhage, synovitis, or fluid extravasation STUDY: superiority of arthroscopy over arthrotomy, in terms of reduced postoperative morbidity, was not supported in a study that compared lameness in normal dogs (BUT used 2.7 scope) STUDY: long-term outcome, arthroscopy resulted in a shorter period of convalescence and a better functional outcome (questionnaire), but there was no significant difference in the development or degree of osteoarthritis STUDY: systematic review and meta-analysis, arthroscopy was found to be superior to medial arthrotomy BUT no randomized clinical trial, illustrating the relatively weak evidence

Answer 56

**Conventional arthrotomy** medial arthrotomy, removal of flap +/- abrasion arthroplasty and penetration of the subchondral bone (by drilling or microfracture) to bring blood supply and cells with chondrogenic potential to the joint surface. **arthroscopy** forceps or an endoscopic motorized shaver STUDY: Long-term clinical and radiographic evaluation shows a significantly worse outcome if OCD present (chronic lame and OA) + SHO does NOT imrpove outcome **OAT** standard medial intermuscular lateral (nonarticulating) aspect of the femoral trochlea Putative benefits: - accurate reconstruction of the subchondral and articular contour, - resurfacing with hyaline or hyaline-like cartilage, - creation of an immediate barrier between synovial fluid and subchondral bone Potential limitations: - donor site morbidity, - invasion of a distant normal joint, - regional differences in cartilage thickness and composition. - Clinical outcome was considered good in the majority of cases, but lack of a control group **osteochondral allograft** - (orthotopic transplantation) same anatomical area as the lesion **synthetic osteochondral transplants** - avoids the limitations inherent to autografts and allografts - titanium base for bony ingrowth - STUDY: SynACart + PUO revealed no complications with good to excellent function. Second-look arthroscopy showed stable implants, quiescent joints BUT 4/6 had MOS grade 4 cartilage wear noted on the medial coronoid process lacking studies comparing SynACart, osteochondral transfer, and fibrocartilage stimulating techniques

Answer 57

- Titanium mesh base - Thermoplastic polycarbonate urethane surface

Answer 58

- Fragment Removal and Subtotal Coronoid - Ostectomy - Biceps Ulnar Release Procedure - Osteotomy of the Radius - Osteotomy of the Ulna - PAUL - Osteotomy of the Humerus - Canine Unicompartmental Elbow - Arthrodesis - Elbow replacement - conservative Tx meds/PRP/Stem cells

Answer 59

probe the medial coronoid process Transection of the fibrous attachments or use shaver (round burr tip (3 to 3.5 mm)), osteotome why coronoidectomy: - Because microcracks can be present (recurrent fragmentation and persistent pain) - improvement of joint incongruence in the presence of positive radioulnar incongruity - Exact guidelines for resection margins of have not been published > my vary according to fragment size - Fitzpatrick et al: the medial portion of the MCP from its medial border to the most caudal extent of the radial incisure cranial to the sagittal ridge of the trochlear notch - Conservative approach: starting osteotomy just caudal to the medial collateral ligament and slightly caudal to the coronoid fissure - Aggressive could significantly reduce the weight-bearing surface of MCP > resulting in humeroulnar conflict with acute end-stage medial compartment disease - fragment removal, without subtotal does not address the underlying cause of the disease > palliative | thorough evaluation of intra-articular structures

Answer 60

treatment option for concept of rotational (transverse-plane) radioulnar incongruity - eccentric attachment of the biceps at the ulnar tuberosity, just distal to abaxial MCP, > muscle contraction produce a large rotational moment in the form of supination - moment rotates the craniolateral border of the MCP against the radial head (compressive stress + microdamage) - BURP eliminate the proximally directed traction at the ulna - tenotomy > cranial to the ulnar tuberosity and just caudal to the medial collateral ligament - Arthroscopically assisted biceps ulnar release, using an arthroscopic push knife, has been shown to be safe - No objective method has demonstrated the clinical contribution of this mechanism of trauma - there is very limited clinical evidence regarding the contribution of rotational dynamic incongruity to the pathogenesis of medial coronoid process disease or regarding the efficacy of the biceps ulnar release procedure

Answer 61

Radial lengthening to correct for short radius radioulnar incongruence (Slocum and Pfeil) osteotomy of the proximal part of the radius + dorsally applied bone plate. - Only limited clinical experiences with inconsistent results canine elbow realignment osteotomy (CERO) allows for precise and reliable correction - using a specially designed string of pearls (SOP) plate (Orthomed) - temporary spacers ranging from 1 to 5 mm - Clinical studies are needed to confirm

Answer 62

Static osteotomies - involve intraoperative lengthening or shortening to correct for radioulnar incongruity followed by stable internal fixation - reduce postoperative morbidity compared to that of dynamic osteotomies; however, precise measurement of incongruity and the correction needed to reestablish congruity = procedural limitation (arthroscopy not help) Dynamic ulnar osteotomies - rely on the forces (tension and compression) acting on the proximal segment to reestablish joint congruence. - dictated by the action of soft tissues, articular interface and loading forces - The pull of the triceps brachii muscle as well as flexor and extensor moments acting on the medial and lateral epicondyles are the most important muscle forces - presence of positive radioulnar incongruity, realignment expected to occur by “pushing” the proximal ulnar segment distally - adult dogs: axial shifts of 4.68 and 0.95 mm reported for proximally and distally performed ulnar osteotomy - varying magnitudes of axial translation and tilting will occur. depends on if interosseus mobilised, IM pin used etc - complications:osteotomy site instability, signs of discomfort, delayed or non-union, excessive callus formation, varus deformity, ulnar fissure fractures and ligament or vessel damage. **Distal dynamic ulnar ostectomy (DDUO)** - abolish the supraphysiological pressure within medial joint compartment by allowing the ulna to slide proximally or distally as needed depending on the type (positive or negative) - in older dogs is not advised because the interosseous ligament is expected to become too strong - may last 2 to 4 weeks - no precise data exist on the elasticity of the interosseous ligament (age), 4 to 6 months of thought to be the maximum age - 4 to 5 mm of ulna - 2 to 3 cm proximal to ulnar epiphysis. - well tolerated, even when performed bilaterally - preserve the periosteal envelope to avoid radioulnar synostosis - =/- arthroscopically assisted fragment removal - ostectomy–treated cases seemed to have only very mild progression of OA **Dynamic proximal ulnar osteotomy/bi-oblique** - BODPUO: junction of the proximal and middle one-third of the radius, with the long axis of the saw blade held at the most acute angle possible relative to the caudolateral cortex of the ulna - Tilting and axial rotation of the proximal ulnar segment can be observed > excessive varus controlled by bi-oblique (fitz) - following DPUO, incongruity only mildly reduced, but the concentration of joint contact at MCP was significantly ameliorated because of caudal tipping - most proximal portion of the interosseous ligament should be elevated - simultaneous bilateral bi-oblique associated with greater risk of postop complications PROS: - unload the medial joint compartment - improve joint congruity - better fit of the opposing joint surfaces - overall increased load-bearing area - combination with local intra-articular treatment of medial coronoid process disease or end stage dz or OCD - Most reports lack a control group; therefore, observed improvement following DPUO might not be related to the procedure alone - comparison of treated with and without DPUO indicates only weak superiority of dynamic (function and progression of OA) - pinning would limit caudal tipping as well as varus deviation - Clinical improvement in end-stage documented objectively using force plate analyisis - On second-look arthroscopy, denuded humeral trochlea covered by fibrocartilage

Answer 63

custom locking plate (Advanced Locking Plate System [ALPS] PAUL, Kyon) - mild abduction - mild caudal tipping - mild axial rotation of the proximal segment derived from assessment of joints radiographed under simulated weight-bearing conditions > Mimicking short radius and subsequently performing a PAUL resulted in normalization of joint congruity. - one specific radioulnar joint cup, which is present in approximately 30% of elbow joints - manufacturer, PAUL unloads the medial compartment and thereby alleviates lameness, stiffness, and joint pain by introducing a slight abduction of the proximal ulna of 4 to 6 degrees - Biomechanical testing: cadaver elbows incongruent due to a short radius confirmed the theory of medial joint unloading. - load does not seem to be transferred from the medial to the lateral joint compartment - STUDY: 64 elbow, end-stage medial compartment disease, improvement in lameness, Age affect prognosis, older dogs performing worse. - reported complication rate is low (5% plate removal) | contraindicated if OA involves lateral compartment of joint

Answer 64

derived from the application of closing wedge osteotomies as tx in human beings with unicompartmental arthrosis of the knee - Based on contact patterns in normal cadaver joints, loads were distributed more equally (approximately 50 : 50) between the radius and the ulna - transmitted through three zones of contact in the elbow joint - uneven distribution of forces across the joint was aggravated by experimental radioulnar incongruity - a lateral translation of the distal portion of the humeral diaphysis relative to the elbow would cause a shift in the radioulnar-humeral mechanical axis. - fibrocartilage at the formerly denuded humeral trochlea prves redction innpressure/friction - Pain scores and owner assessments of function generally improved and lameness resolved in approximately 66% of dogs available for follow-up - initial complication rate was high, 19% (5% major complications) related to failure or instability of the bone-implant construct STUDY: proximal segment, where shear loading appears to concentrate > locking screw created + stepped plate - reduced the complication rate to 4.17% with no major complications. Lameness resolved in 49 of 60 limbs. STUDY: 18 dogs, Significant improvement in ground reaction force | contraindicated if OA involves lateral compartment of joint

Answer 65

- Pain related to end-stage medial compartment disease is thought to arise from bone-on-bone contact - Reestablishing articular contact surfaces (focal joint resurfacing) could improve load transmission and joint kinematics, clinical function and ameliorate associated pain - contraindicated if osteoarthritis involves the lateral compartment of the elbow joint compare favorably with that of total elbow joint replacement BUT cannot be considered as minimally invasive: - subluxation of the joint - tenotomy of the flexor tendons - desmotomy of MCL or osteotomy of medial epicondyle - 4 to 6 mm diameter polyethylene plug in MCP (porous titanium socket for bone ingrowth) - figure eight”–shaped cobalt chrome prosthesis into opposing humeral trochlea - press-fit - humeral implant slightly proud to restore normal joint space width > relieves pressure on the denuded joint surfaces around the implant + counterbalances the varus deviation STUDY: multicenter, prospective (103 cases) (follow-up 10 months), catastrophic (1%), 11 major (10.7%), and minor (27.2%) complications. Functional outcomes: full (47.6%), acceptable (43.7%), and unacceptable (8.7%) - CUE limited to MCPD (UAP is more lateral) complications - avulsion or nonunion of the medial epicondyle, - implant malpositioning - incisional/extraarticular infection - persistent pain and lameness | safe, effective, consistent, repeatable and clinically practical

Answer 66

- alleviates pain associated with osteoarthritis, - results in substantial loss of function and limb circumduction. - limited to cases with loss of articular cartilage in the medial and lateral + if elbow replacement not an option

Answer 67

- several retrospetive studies did not demonstrate significant differences in radiographic/physical/force plate evaluation in dogs treated medically versus surgically **Evans and de Lahunta** - compared arthroscopy, medial arthrotomy, and medical in a meta-analysis of more than 400 candidate manuscripts. - arthroscopy was superior to medial arthrotomy and medical management, - overall weak evidence from most studies, definitive conclusions on the effectiveness of conservative management are not possible.

Answer 68

CCS, hyaluronic acid, autologous conditioned plasma or platelet-rich plasma - reported to improve limb function for up to 6 months - results are encouraging, and further studies are warranted - limited duration, therefore the need for repeated injections, as well as the associated costs, have limited widespread use. stem cells - autologous adipose-derived mesenchymal stem cells - (IL-1RA) might play a key role. - prospective, randomized, placebo-controlled efficacy study: adipose stem cells in 74 dogs with osteoarthritis affecting one or two joints (primarily hip and elbow joints) showed positive results - Relatively small group size, significant group differences in limb function and degree of osteoarthritis reduce strength of results Acupuncture (no strong evidence) other meds???

Answer 69

- pain management - rehabilitation - multomodal management for osteoarthritis (weight management, nutritional supplementation, physical rehabilitation, and antiinflammatory medications) - restricted activity for 4 to 6 weeks (1) the immediate motion phase (weeks 1 to 3), (2) the intermediate phase (weeks 4 to 6), (3) the advanced strengthening phase (weeks 7 to 11) (4) return to activity (weeks ≥12) - positive impact of early motion on joint homeostasis, preservation of range of motion, and muscle mass justifies the routine use of this therapy in dogs

Answer 70

- disturbance of endochondral ossification takes place < 20 weeks of age, thus available tx must be regarded as palliative or, at best, disease modifying. - preventive cure for MCPD is not available. - validated juvenile screening tool does not exist **early MCPD** Removal of the fragment - may reduce irritation and pain - Arthroscopy lowers surgical risks, provides improved visual assessment, and results in better functional outcome than arthrotomy - debatable whether removal of the fragment impacts the progression of osteoarthritis - lack of definitive evidence that fragment removal improves joint health and positively alters dz coronoidectomy - Studies comparing fragment removal to subtotal are lacking; therefore, benefit of subtotal ostectomy remains unclear - excessive resection > introduction of joint instability and load concentration - Fragment removal is less invasive, does not induce further joint damage or alteration in biomechanics other than those already present, and, subjectively, the risk of refragmentation seems to be negligible Only very weak evidence for protective effect of bi-oblique dynamic DPUO in cases of early medial coronoid process disease. **Diseased MCP** cartilage abrasion at the medial coronoid process, mechanical overload within the medial joint compartment has to be considered Mechanical unloading of the diseased area of the medial coronoid process > subtotal or bi-oblique **Diseased humerus** wear lines of the humeral trochlea are affected by a more serious mechanical dysfunction than elbow joints with simple fragmentation/fissure alone Humeroulnar conflict could be due to mechanical overload, joint instability, and/or humeroulnar incongruity > Mechanical unloading of the diseased area may be achieved by the described osteotomies **Advanced medial compartment disease** salvage procedures aiming at unloading the medial joint compartment - macroscopically normal-looking joint cartilage within the lateral joint compartment has to be present - SHO/PAUL/BIoPUO demonstrated efficacy for improvement - CUE **global joint involvement** (medial and lateral) - TER - arthrodesis

Answer 71

mid- and long-term prognosis for MCPD/OCD + efficacy of current treatment options, remains poorly defined. - Most studies report improvement in lameness in 50% to 100% of cases, despite radiographic progression of osteoarthritis. - Functional improvement is noted in an average of 85% of cases - FMCP and OCD warrants guarded to poor prognosis end-stage medial compartment disease bears a favorable prognosis, regardless of the surgical technique. - Up to 90% good to excellent functional outcomes have been reported, mostly using subjective evaluation - The rate of serious complications is least for DPUO < PAUL < CUE < SHO - Several procedures are often combined, prevents discrimination of the individual - outcome are often limited to subjective data, outcome is not standardized and varies between studies, often small numbers > affects the ability to identify statistical significance in differences between treatment groups - Most long-term (>6 months) studies report a progression of osteoarthritis in most, if not all, dogs evaluated, regardless of the treatment evaluated - Large-scale postoperative studies using kinetic gait analysis are lacking

Answer 72

Ex vivo cadaveric study. Sample population: Canine thoracic limbs (n = 15 limb pairs). There were differences in five of 12 limb alignment values pre-PAUL and post-PAUL in standing and recumbent positions increase in mechanical medial proximal radioulnar angle and a decrease in elbow compression angle In the ex vivo setting, PAUL resulted in translation of the mechanical axis of the thoracic limb from a medial to lateral direction The results of the present study provide evidence that in the ex vivo setting PAUL3 has more dramatic effects on limb alignment values compared with PAUL2 use of contact pressure systems in small, confined, curvilinear joints is prone to a number of data recording errors.

Answer 73

retrospective clinical study. Materials and Methods Records from 30 dogs Outcome was assessed via owner questionnaire CBPI score for dogs in the PAUL group was not significantly different from the control group. nsaid administration was similar between groups and there was no significant difference between modified Outerbridge score and outcome over a median of 43 months post-surgically PAUL showed no owner-assessed benefit over arthroscopic with medial compartment disease and modified Outerbridge score of 3 or greater. A prospective clinical trial is warranted This finding demonstrates that pain associated with elbow disease progresses with time irrespective of treatment. Previous non-peer reviewed studies on the PAUL procedure have reported a poor response rate in older dogs which is consistent with the findings reported here > unknown if early interventionwith PAUL, prior to the onset of osteoarthritis, would improve outcome in dogs with medial compartment disease. McConkey and colleagues recently demonstrated that the contact area in the joint decreased in the medial compartment, but was not increased in the lateral compartment following PAUL procedure. They hypothesized a pressure transfer to the anconeal process

Answer 74

Retrospective review, Lateral luxations were most common (n = 21 14/25 cases underwent primary surgical reduction and 11/25 were secondary procedures following failure of closed reduction. Transcondylar bone tunnels and circumferential suture (n = 19) most common. Catastrophic (n = 1), major (n = 11) and minor complications (n = 5) reluxation (61%) > after closed reduction (n = 8) than after open (n = 0) + was associated with increased injury duration outcome was good-excellent in 10/12> eight of 31 surviving cats were reported to be lame on clinical follow-up three elbows initially judged as stable by Campbell’s test that later luxated (72hr-6weeks) in humans, dislocations are assessed fluoroscopically in varus and valgus stress following closed reduction Compared with dogs, cats have increased thoracic limb dexterity, conferred by shallower trochlear furrows, larger and distally-projecting humeral trochleas and smaller anconeal processes Additionally, feline oblique and olecranon ligaments are relatively large compared to those of dogs, and act as important secondary stabilisers mean pronation angle of approximately 50° and a mean supination angle of approximately 129° in feline cadaveric elbows with intact collateral ligaments increased severity of damage to the collateral ligaments in the cats (explain increase reluc compared to 30% dogs)

Answer 75

studied 99 elbows results do not identify a significant difference in axial radioulnar congruity between the radial incisure and apical MCP protocol used in our study to measure joint space in the transverse plane, even though consistent between observers, has not been validated, no control group Abnormal ulnar morphology in the radial incisure group could result in a fulcrum effect within the radioulnar joint, overloading the radial incisure and predisposing to osteochondral damage at this site. can exclude genetic contribution to the development of either radial incisure or apical fragmentation Fluoroscopic kinematography studies have quantified dynamic change in humeroradioulnar articulation, revealing axial incongruity of similar magnitude in both normal and dysplastic elbows (Rohwedder et al. 2017), as well as increased rotational humeroulnar laxity in dysplastic elbows (Rohwedder et al. 2018).

Answer 76

Retrospective review First-line treatment was Penrose drain placement in 12 and complete surgical excision in nine. Bilateral hygromas were addressed simultaneously 4/12 hygromas managed with Penrose drain recurred and one developed ulceration Clinical Significance: Surgical excision of canine elbow hygroma is an effective technique that appears to have fewer postoperative complications than Penrose drain placement.

Answer 77

retrospective case series. Results Six cases A non-locking 2.7/3.5- mm precontoured elbow arthrodesis plate mean angle of arthrodesis was 118° One major intraoperative complication occurred (radius #). Three minor (implant migratino, radial neuropraxia) and 3 major (spint related + recurrence of sinus drainage tracts) postoperative complications occurred Complete arthrodesis was confirmed by imaging in 4/5 cases, partial in one Subjective outcomes in the remaining three cases were rated as acceptable more than 1 year postoperatively high rate of complications in this case series All five cases were able to ambulate but often with a lameness which required activity to be limited in duration, the administration of analgesic medications, or a combination of both to achieve improvement in gait The pre-contoured plate resulted in a narrower range in angle of arthrodesis (113–130°) compared to the previous report using either a caudally applied bone plate, lag screws or Kirschner wires (85° and 145°). current plate > width is increased in themid-section in the region of greatest bending force Three cases had an elbow arthrodesis following explantation of a total elbow replacement Olecranon osteotomy has been previously reported to have a complicationrate of37%

Answer 78

retrospective, Eight dogs Five of the eight dogs had surgical revision of lateral radial head subluxation. Resolution of lateral radial head subluxation was achieved in four dogs Such subluxation is debilitating and appears to result from ulnar osteotomy instability. a greater proportion of lateral radial head subluxation dogs had angular limb deformities > cofounding factor five of eight dogs had different concurrent procedures performed | interosseus ligament release??

Answer 79

Retrospective. complications after PAUL (n=66 dogs) - overall complications 19/74 (25.7%), 13/19 (17.6%) major - major complications: non-union, implant failure, infection, distal ulnar fracture - body weight associated with increased risk of complications - post-operative radiographs not predictive of complications (plate and screw placement or osteotomy reduction) did not attempt to evaluate the clinical outcomes. Performing PAUL in juvenile patients remains controversial and may even be contra-indicated implant removal of other clean orthopedic procedures (2.6%–7.4%). PAUL implants has recently released new conical screws > expected to make the entire construct stiffer; may reduce instability at the osteotomy

Answer 80

retrospective, 67 clinically affected elbow joints (67 dogs) with MCPD on CT fragments were removed in 30 elbows, chondroplasty of themedial coronoid process onlywas performed in 10 elbows and 4 elbows had inspection only used CBPI to compare arthroscopy and conservative management in dogs with medial compartment disease, and also showed no significant difference in long-term outcome. For LOAD, PSS and PIS, older age at diagnosis was all significantly associated with higher scores did not report the severity of cartilage erosion for MC tx only group, making comparison of these findings difficult. Dogs in the AI groupwere significantly older at the time of questionnaire completion those dogs with bilateral disease may have confounded our results prospective required > Without these studies, the decision-making process for the management ofMCPDwill remain, to a large extent, amatter of opinion and therefore of controversy. Burton NJ Conservative versus arthroscopic management for medial coronoid process disease in dogs: a prospective gait evaluation. Vet Surg 2011

Answer 81

retrospective, 82 client-owned dogs (93 limbs) Postoperative complications were documented in 39 limbs (13 major and 26 minor). The most common major complication was osteotomy nonunion (8 limbs), while the most common minor complication was delayed union (21 limbs). Statistical analysis revealed that lower body weight (P = .01) and older age (P = .04) were significantly associated with the development of postoperative complications oligotrophic nonunion> excessive motion or inadequate cellular activity at the osteotomy (predisposed by iatrogenic thermal necrosis) lighter-weight dogs were chondrodystrophic dogs risk for angular deviation at the osteotomy site because any mechanical forces applied along the bone would be more eccentric 15 of 17 dogs older than 24 months experienced complications osteotomy angle did not influence the complication rate. 50 of 93 limbs in our study, the interosseous ligament was deliberately disrupted > univariate analysis failed to identify any significant association and the development of complications

Answer 82

The left trochlear notch is markedly flattened with irregular margins and lamellar/smooth solid periosteal reaction. The left anconeal process is blunted. The soft tissues of the left lateral elbow have heterogeneous mineralization potentially secondary to surgery. At the most recent review, 7 months postoperatively, the lameness had become moderate weight-bearing lameness

Answer 83

Prospective. 15. Ultrasonography in dx of Medial Compartment Disease > rad and CT did not lead to a clear diagnosis At least one ultrasonographic lesion 13 out of 15 elbows. - joint effusion (10/15 elbows) - abnormal shape MCP (9/15). transducer can assess soft tissues and medial compartment, but not the articular cartilage may have value in early diagnosis for process fissuring (rad and CT less sensitive)

Answer 84

Attenuation of the MCP reduced in dogs with MCD compared with those with no MCD (P < .002). good inter- and intraobserver agreement may be a useful tool for early detection of MCD

Answer 85

prospective, RCCT. 16. Arthroscopic Subtotal Coronoidectomy +/- Concurrent Autologous Conditioned Plasma 16 dogs with unilateral medial coronoid disease - no difference between ACP and placebo groups - ground reaction forces decreased initially then propulsive and vertical forces reached normal by 26 weeks - braking forces did not reach normal - visual improvement in all dogs, 10/16 not lame at 26w outcome of arthroscopic less favourable than previously reported > limitations of subtotal coronoidectomy (bone fragments, scar tissue and progressive osteoarthritis) Normalizing GRF based only on body weight may not be sufficient for analysing dogs of different breeds

Answer 86

7. retrospectively. CT-guided cannulated lag screw placement for UAP seroma formation (n = 1) and major SSI (2) > 2 implant removal (in GSD) All radiographic union, partial 5/8 complete 3/8. arthrosis scores remained static in all patients. 2/7 had no PUO performed. confounded by treatment of incongruity or FMCP fibrous bridging of the anconeal not determined arthroscopically prior to lag screw > CT-guided more difficult on loose fragments; Prolonged anesthetic, reduced level of asepsis seroma > SF thru screw (Bone wax was placed in the screw head Countersinking not performed > distribute forces against the screw head evenly to reduce the risk of fracture +/- reduce soft tissue irritation and seroma formation.

Answer 87

Retrospective. 38 Labrador (total of 76 elbows). (CT) images Subchondral bone cysts identified in elbows with osteophytic new bone formation. Subchondral bone cysts were identified as a feature of radiographic elbow osteoarthritis in Labrador retrievers, and their number and size were indicative of the presence and severity of radiographic elbow OA (clinical severity correlation unknown) not confirmed histologically tendency for SBCs to form within the medial compartment of the elbow.

Answer 88

11. retrospective short radius syndrome treated with acute arthroscopically assisted ulnar shortening Radiographic and arthroscopic articulation improved short-term (9 weeks) clinical improvement in all dogs. - planned ostectomy length = measured radioulnar distance + 2–3 mm ostectomy of the ulna > fragments compressed under arthroscopic control until radiohumeral articulation is considered optimal (surgeons personal experience). Plate applied. coronoidectomy also was performed No major complications occurred. 4 dogs > follow-up 2 years > LOAD scores suggesting no progression to severe elbow arthrosis or chronic pain - RUI treatment has been recommended if >2–3 mm Alternatives: PUO, ESF

Answer 89

Prospective. correlation between static and dynamic RUI in MCPD incongruence > sphere fitting technique. radiostereometric analysis MCD joints had mean positive sRUI (1.4mm) vs controls (0.2mm) - controls → negative mean dRUI (-0.4mm) versus MCD (1.4mm) - dynamic and slightly negative RUI occurs during loading of normal elbows - developed just before stance phase → potential protective muscle contraction - no dynamic change in RUI at walk in MCD joints > sRUI persists in canine elbowjoints with MCPD during walk - CT-based measurement of sRUI comparable to in vivo situation MCPD > radioulnar motion is decreased primary mechanism or a secondary result of the disease process? angular vector model (AVM) > As negative dRUI was measured in sound elbow joints only, increase in mechanical overload due to the described negative dRUI, can be excluded.

Answer 90

static RUI reduced (2.3-1.5) but not normalised, no effect on dynamic RUI - joint contact area at MCP increased → more homogenous distribution, which can still lead to functional improvement.

Answer 91

Review incongruity. - elbow is a complex joint and structures in contact differ in different phases of the gait cycle - Positive RUI (short radius) recognized as major cause > chronic supra-physiological load recent in vivo fluoroscopic studies: dynamic RUI equally present in normal and dysplastic (therefore dynamic less likely cause) Humeroulnar incongruity, condition is less reported > some uncertainty ulnar trochlear notch and humeral trochlea shape: current concept of the canine elbow conformation does not mean a perfect match of congruence. small physiological concave incongruity = accepted normal joint forces mapping > three distinct contact areas on the canine elbow: caudomedial radial head, MCP and craniolateral anconeus Contrary to large breeds, small breeds > located more centrally load transfer up to 50% of forces borne by themedial and the lateral coronoid processes and the rest by the radial head scope: direct visualization and simultaneous tx incongruity > sensitivity 94 to 98% and specificity of 81 to 89%, Coronoid pathology was evident in every incongruent joints. micro-ct > subchondral bone plate remodels and appears to thicken before degradation of the overlying articular cartilage in osteoarthritis genetics inherited polygenic traits, differences between breeds Elbow anatomy and incongruity nfluenced by genetics phenotypic heterogeneity makes it difficult to determine the genetic background challenges RUI techniques > low joint space tolerance, variation in the interpretation, elbow positioning, and loading, which brings subjectivity to the methods

Answer 92

Review of MI tx for MCPD 60 papers, Six prospective with gait analysis, three with control group. conclusion - small case numbers, all studies employing a control group failed to demonstrate superiority of surgery over nonsurgical management. - 3 gait analysis and no control > some improvement in function compared to pretreatment - Multiple studies document progression of osteoarthritis > +/- synonymous with worsened function. - Subtotal coronoid osteotomy (SCO) > long-term biomechanical consequences unclear and quantitative data on the efficacy awaited. - studies need to be more defined re age, incongruity and the precise arthroscopic findings RUI and MCPD Work by Lau et al > lab puppies compared, determines elbow incongruity is not the inciting cause of MCPD as MCP pathology develop in the absence of incongruity. positive correlation between the magnitude of incongruity and the severity of medial compartment articular damage Fragment removal Second look arthroscopy confirmed that fragment removal does not arrest the progression of osteoarthritis. - no longitudinal objective study that has evaluated whether early fragment removal result in slower progression of osteoarthritis. A subsequent meta-analysis arthroscopy was superior to arthrotomy and medical ttreatment of MCPD. Based on poor studies - majority advocated MCP fragment removal have not employed objective outcome measures or a control group BURP 10% MCL damage. clinical series BURP as a sole treatment with objective outcome currently lacking. Subtotal coronoidectomy Histopathological > microcracks may be incipient adjacent to fissure or fragment - STUDY> CT immediately following subtotal coronoid osteotomy (SCO) revealed apical completely removed 72% of cases but only 5% of radial - unknown optimum commencement position and angle of osteotomy - Studies are lacking on the biomechanical consequences of SCO on the medial joint compartment. “Impingement syndrome” shown if too much taken

Answer 93

Arthroscopic fragment removal for traumatic fracture of the MCP has previously been described in 24 dogs. This condition is considered a separate entity to MCPD with a single, large fracture fragment being appreciated in all cases with no adjunctive articular pathology. Subjective short-term outcome in this case series was excellent following fragment removal.

Answer 94

retrospective 8 cats. 5 lateral. 3 medial. age 9yr. Tx > closed reduction and percutaneous placement of a temporary transarticular type II ESF, which was removed 2 weeks postoperatively Elbow reluxation and major complications were not encountered All cats demonstrated an excellent outcome based on the lameness score

Answer 95

CT study screening for elbow dysplasia prior to breeding were evaluated. 86 elbows in asymptomatic dogs. Guide Dogs had significantly higher minimum, mean and maximum difference in HU within the medial coronoid process ROI and humeral trochlea ROI. data suggest that sclerosis in these regions may represent a breed or population variation and not necessarily an association with elbow dysplasia asymptomatic Guide Dogs have increased HU measurements within the subchondral bone of the humeral trochlea and MCP > consider in breeding screening programmes to avoid over-interpretation of elbow sclerosis, in the absence of elbow pathology

Answer 96

ex vivo. asess if level, angle, roation or orientation of humeral osteotomy. affect pressure through themedial compartment of the elbow Performing an osteotomy at a more distal location along the humerus and increasing the angle of the induced change increased the effectiveness of loadshifting humeral osteotomies. > 3D printed plate with wedge. Performing the osteotomy at 75% of humeral length, Opening wedge osteotomies were more effective than external rotational osteotomies, but both were effective Aspects such as adverse effects on limb alignment, soft-tissue loading, and bone healing need to be carefully considered in clincal studies

Ch 52 Elbow disease Flashcards

(129 cards)