Osteochondrosis of the elbow: a review of the pathogenesis and a new approach to treatment

SUMMARY To test the hypothesis that joint incongruity contributes to the pathogenesis of elbow osteochondrosis, the left and right radius and ulna of 20 young large breed dogs were measured to determine any variation in length and to observe any incongruity of the elbow joint. Both lame and normal dogs were included in the study. Nine of the 20 dogs had marked disparity in radial and ulnar lengths yet only one had obvious elbow joint incongruity. The use of a sliding osteotomy for the treatment of fragmented coronoid process and a lengthening osteotomy for the treatment of an ununited anconeal process is also discussed. All four dogs treated with a sliding osteotomy showed a marked clinical improvement, and two of the three dogs treated with a lengthening osteotomy showed radiographic fusion of the anconeal process.     

Comparison of Three Methods of Ulnar Fixation in Horses

Objective- This study compares the mechanical properties of three methods of equine ulnar fixation: dynamic compression plating, pins and wires tension band, and a prototype grip system.
Study Design- The mechanical properties of dynamic compression plating, pins and wires tension band, and a prototype grip system repair of equine ulnar fractures were evaluated in a cadaveric osteotomy model.
Animals or Sample Population- Fifteen pairs of the radius and ulna from equine cadavers.
Methods- The three repair techniques were evaluated to mimic the pull of the triceps brachii muscle in single cycle to failure and in cyclic fatigue loading. Single cycle results were evaluated as the axial and angular displacement. Cyclic fatigue results were evaluated as the number of cycles to failure.
Results- Dynamic compression plate fixation and pins and wires tension band had significantly less axial displacement of the proximal fragment than the grip system ( P <.05). No significant difference in angular rotation of the proximal fragment was present between the three techniques. Dynamic compression plating had significantly greater fatigue resistance than the grip system ( P <.05). Cyclic failure was characterized by screw loosening or breakage and wire breakage.
Conclusions- Dynamic compression plates were better than the other techniques at maintaining compression of a transverse ulnar osteotomy at the level of the anconeal process just proximal to the trochlear notch.
Clinical Relevance- Knowledge of fixation technique mechanical properties is essential for surgeons to select the proper method of fracture repair.     

Co-existence of ununited anconeal process and fragmented medial coronoid process of the ulna in the dog

OBJECTIVES: To determine the incidence of fragmented medial coronoid process of the ulna in dogs with ununited anconeal process. The efficacy of presurgical radiography to diagnose the co-existence of these diseases was also investigated. METHODS: One hundred and fifty-five joints from 137 dogs with ununited anconeal process were included in the study. For the radiographic examinations, an extended mediolateral projection and a craniolateral-caudomedial oblique projection of each elbow joint were taken before surgery. Inspection of the medial part of the joint was carried out either by arthrotomy or arthroscopy. RESULTS: Seventy-two per cent of the dogs were German shepherd dogs. In 25 joints (16 per cent) a fragmented medial coronoid process was diagnosed and removed via arthrotomy or arthroscopy. The co-existence of a fragmented medial coronoid process was diagnosed correctly in only 13 cases (52 per cent) by radiography. In five of these cases with advanced osteoarthritis, the fragment was directly visible because of its dislocation. Compared with published information, the occurrence of ununited anconeal process with fragmented medial coronoid process is noted more frequently in the present study. CLINICAL SIGNIFICANCE: It can be summarised that if ununited anconeal process is present, it is not usually possible to clearly identify fragmented medial coronoid process by radiography. Therefore, it is important to be able to inspect the medial aspect of the joint concerned during surgery.     

Radiographic Evaluation of the Anconeal Process in Skeletally Immature Dogs

Objective: To determine if a secondary center of ossification (SCO) of the anconeal process is present in skeletally immature dogs that do not develop an ununited anconeal process (UAP). Study Design: Case series. Animals: Dogs 77–154 days of age with conditions other than developmental disease of the elbow (n=78 dogs; total elbows=100). Methods: Mediolateral radiographic projections of the elbow were reviewed for presence or absence of a SCO of the anconeal process. Results: A SCO was radiographically evident in 16% of elbows from breeds that have been reported to be affected by UAP. The appearance of the SCO was different to an UAP fragment. None of the elbows with SCO of the anconeal process developed UAP. A SCO was not present in any small breed dogs. Conclusions: A SCO of the anconeal process is uncommon in medium and large breed dogs and the presence of a SCO does not indicate that UAP will develop. Clinical Relevance: Because radiographic diagnosis of a SCO of the anconeal process and UAP lesions have distinct appearances, an earlier diagnosis of UAP is possible.     

Radiographic changes in elbow dysplasia following ulnar osteotomy--a case report and review of the literature

This case report describes the results of bilateral elbow arthrotomy and a unilateral ulnar osteotomy in a 10-month-old dog with bilateral elbow dysplasia. Fragmented coronoid processes were removed from both joints via bilateral medial arthrotomies. On the right side an ulnar osteotomy was also performed using a caudolateral approach. Bilateral flexed lateral elbow radiographs taken before surgery and 5 months postoperatively were assessed for changes in osteophyte size on the anconeal process, caudal epicondylar ridge and radial head. Osteophytes on the anconeal process and caudal epicondylar ridge disappeared over the postoperative period in the joint that received an ulnar osteotomy. In the contralateral joint the size of the oesteophytes on the anconeal process and caudal epicondylar ridge increased in size during the same period.     

Antebrachial deformities in the dog: Treatment with external fixation

The results of 12 dogs with antebrachial deformity treated by ulnar ostectomy, radial osteotomy and external skeletal fixation are presented. Postoperative complications were seen in only one dog; a delayed union requiring placement of autogenous cancellous bone graft at a second surgery to achieve healing. Postoperatively, owners reported limb function was good in almost all cases, although they were less pleased with the cosmetic appearance.     

Short incomplete sagittal fractures of the proximal phalanx in ten horses not used for racing

Objective— To describe short incomplete sagittal fractures of the proximal phalanx (type Ia P1 fractures) in horses not used for racing and report outcome.
Study Design— Retrospective study.
Animals— Horses (n=10) with type Ia P1 fractures.
Methods— Retrieved data of horses with type Ia P1 fractures were signalment, history and results of orthopedic examination. Radiographs were re-evaluated for position and length of the fracture line, presence of osteoarthritis or subchondral cystic lesions (SCL), periosteal new bone formation and subchondral sclerosis. Conservative treatment (n=4) included box confinement for 2 months followed by 1 month of hand walking. Surgical therapy (n=6) consisted of internal fixation by screws inserted in lag fashion in 5 horses. Concurrent SCL were debrided by curettage via a transcortical drilling approach. In 1 horse, only SCL curettage but not internal fixation was performed. Outcome was assessed on a clinical and radiographic follow-up examination in all horses.
Results— Mean follow-up time was 27 months (median, 13.5 months; range, 9 months to 9 years). All horses treated with internal fixation were sound at follow-up and had radiographic fracture healing. Of the 4 horses managed conservatively, 3 remained lame and only 1 horse had radiographic evidence of fracture healing. Catastrophic fracture propagation occurred in 2 horses not treated by internal fixation, 20 and 30 months after diagnosis, respectively.
Conclusions— Horses with a type Ia P1 fracture treated surgically had a better outcome than those managed conservatively and lack of fracture healing seemingly increases the risk of later catastrophic fracture.
Clinical Relevance— Surgical repair of type Ia P1 fractures should be considered to optimize healing and return to athletic use.     

CORRELATION OF RADIOGRAPHIC, NECROPSY AND HISTOLOGIC FINDINGS IN 8 DOGS WITH ELBOW DYSPLASIA

Elbow dysplasia is osteoarthrosis/degenerative joint disease due to abnormal development of the elbow joint. The abnormaldevelopment is the result of specific inherited etiologies alone or in combination. This paper attempts to clarify the diagnosis of elbow dysplasia based on the presence of degenerative joint disease by correlating rediographic necropsy, necropsy, and histopathologic results using elbows from 8 German Shepherd dogs. All elbows had radiographic changes consistent with osteoarthrosis/degenerativejoint disease which were identified best on the flexedmedial-lateral projection. Radiographically, a specific diagnosis was made inseven elbows; ununited anconeal process(6) and osteochondrosis (1). At necropsy these lesions were confirmed plus 14 elbows were identified that had fragmented medial coronoid process (6), abnormally shaped medial coronoid processes of fissures in the articualr cartilage of the medial coronoid process (8). additionally, histopathologically there was proliferative synovitis at the radial notch of the ulna and degenerative changes on the proximal, nonarticualr surface of the anconeal process at the site of insertion of the olecranon ligament and joint capsule.Therefore, for screening the elbow joint to identify elbow dysplasia, the recognition of osteoarthrosis/degenerative joint disease on an extreme flexed mediolateral rediograph appears to be sufficient.     

The Effects of Fixation of the Ulna to the Radius in Young Foals

The effects of radioulnar fixation were studied in 21 Quarter horse foals by applying a bone plate to the caudal aspect of the proximal part of the ulna, with screws engaging both the radius and the ulna. The plates were applied at 1 month of age in six foals (group I), 5 months of age in six foals (group II), and 7 months of age in three foals (group III). Six foals underwent sham operations at 1 month of age to serve as controls (group IV). Ulnar dysplasia and elbow subluxation developed in all treated foals. The magnitude of ulnar dysplasia was inversely related to the patient's age at fixation and was accompanied by degenerative joint disease and lameness in foals undergoing fixation at 1 and 5 months of age. Removal of the fixation appliances 16 weeks after implantation in three foals from each of groups I and II failed to reverse the degree of ulnar dysplasia. Although foals undergoing fixation at 7 months of age (group III) were not lame, radiographic evidence of subluxation and subtle degenerative changes in the articular cartilage of the treated elbow did develop. Recommendations for avoidance of radioulnar fixation were developed from these observations.     

Radiographic diagnosis and surgical management of fragmented medial coronoid process in dogs

The diagnosis of fragmented (ununited) medial coronoid process was made in 21 dogs, with 10 dogs having bilateral lesions. Ten of these dogs were presented to surgery. The diagnosis of fragmented medial coronoid process was made in young and middle-aged large- and giant-breed dogs with a history of intermittent or persistent lameness. Diagnosis was based on history as well as results of clinical examination and radiographic study of both elbows. Concomitant elbow lesions seen with fragmented medial coronoid processes were ununited anconeal process and osteochondritis dissecans of the medial humeral condyle. Avulsion of the medial epicondyle and posteromedial supracondylar ridge of the humerus were thought not to have occurred in these cases. Instead, dystrophic ossification of the synovial membrane and periosteal proliferation on the medial epicondyle and posteromedial supracondylar ridge had taken place. It was concluded that, with a questionable radiographic diagnosis of fragmented medial coronoid process, exploratory arthrotomy may be necessary to confirm the diagnosis. Without surgery, the eventual outcome of fragmented coronoid process is degenerative joint disease. Even with degenerative joint disease, however, clinical improvement was seen following removal of the fragment of the medial coronoid process.     

Assessment of the geometry of the cubital (elbow) joint of dogs by use of magnetic resonance imaging

OBJECTIVE: To assess joint geometry and highlight potential evidence of physiologic incongruity in cubital (elbow) joints of large, small, and chondrodystrophic breeds of dogs. SAMPLE POPULATION: Nonarthritic elbow joints obtained from cadavers of mature dogs of large breeds (n = 19), small breeds (14), or chondrodystrophic breeds (8). PROCEDURE: Magnetic resonance imaging was used to quantify interosseous gaps at 6 defined positions and 2 sagittal planes of the humeroantebrachial region by use of a fat-suppressed 3-dimensional gradient-echo sequence. RESULTS: Interosseous gaps in the more medially located sagittal plane were significantly narrower at the level of the anconeal process than at any other position of the joint in large-breed dogs, compared with results for small- or chondrodystrophic-breed dogs. In both sagittal planes, the gaps were significantly wider at the center of the ulnar trochlear notch than at any other position. Significant correlation between body weight and width of the interosseous gaps was found only in large-breed dogs and was found in both sagittal planes at the center of the ulnar trochlear notch (r, 0.834 and r, 0.680, respectively). CONCLUSIONS AND CLINICAL RELEVANCE: In large-breed dogs, the interosseous gap was especially narrow at the level of the anconeal process and its diametric position. This suggests less ability to compensate intra-articular steps in dogs with short ulna syndrome, which predisposes to failure of the union between the anconeal process and olecranon. Geometric incongruity may be regarded as clinically normal in nonarthritic humeroulnar joints. The degree of geometric incongruity increases with body weight.     

Variation in the ossification process of the anconeal and medial coronoid processes of the canine ulna

This morphological and radiographic study investigates the ossification process of the anconeal and medial coronoid processes of the ulna in a sample of 142 dogs ranging in age from neonatal to 44 weeks. The anconeal process was noted to develop by appositional ossification, formation of a separate ossification center, or a combination of both. Several developmental stages of the ossification center of the anconeal process as well as its anatomic position and radiographic appearance are described. Differences have been noted in the shape of this ossification center as well as the ossification process itself. The medial coronoid process develops exclusively by appositional ossification. Unlike ossification of the anconeal process, ossification of the medial coronoid process was completed earlier (p < 0.05) in smaller than in the larger dogs. In smaller dogs, both the medial coronoid and anconeal processes were found to be mature by the age of 16 weeks. In the larger dogs, ossification of the anconeal process was completed not before 14 weeks of age and ossification of the medial coronoid process was completed about 6 weeks later.     

In vitro comparison of proximal ulnar osteotomy and distal ulnar osteotomy with release of the interosseous ligament in a canine model

Objective: To determine the effect of proximal ulnar osteotomy (PUO), distal ulnar osteotomy (DUO), and DUO with release of the interosseous ligament (DOLR) on displacement of the proximal ulna at the radioulnar joint. Study Design: Experimental mechanical study. Sample Population: Cadaveric, skeletally mature canine thoracic limb pairs (n=11). Methods: Thoracic limbs disarticulated at the elbow were randomly assigned to 1 of 2 groups: (A) limbs were tested with no treatment (NOTX), then with PUO; (B) limbs were tested with DUO followed by DOLR. A distraction force was applied to the proximal ulna with the distal limb secured in a frame, and displacement of the proximal ulnar segment at the radioulnar joint was recorded. Results: Mean displacement was 0.36 mm (95% confidence interval [CI]: 0?1.12 mm) in the NOTX group, 4.68 mm (95% CI: 3.82–5.55 mm) for PUO limbs, 0.95 mm (95% CI: 0.52–1.39 mm) for the DUO group, and 4.36 mm (95% CI: 3.71–5.02 mm) for the DOLR group. Mean ulnar displacement of the DOLR group was significantly different compared with the DUO group, but there was no significant difference between the PUO and DOLR groups. Conclusions: No significant difference was observed in displacement of the proximal ulnar segment after DOLR compared with PUO.     

Correction of Rotational Deformity of the Pes with External Skeletal Fixation in Four Dogs

Objective— To report unilateral correction and initial stabilization with external skeletal fixation (ESF) of metatarsal rotation in 4 immature Bernese Mountain Dogs.
Study Design— Case series.
Animals— Bernese Mountain Dogs (n=4).
Methods— The limb deformity, including degree and origin of the deformity at the level of the proximal intertarsal joint and involvement of the central tarsal bone, was characterized by clinical and radiographic assessment. Unilateral surgical correction of the most severely affected limb was performed by disrupting the ligaments and debriding the articular cartilage of the proximal intertarsal joint to allow for derotation of the deformity and arthrodesis of the proximal intertarsal joint stabilized with either circular or linear ESF.
Results— Initial metatarsal rotation of the corrected limbs ranged from 60° to 80° of external rotation (mean, 72.5°). Three limb corrections were stabilized with circular ESF and 1 with a biplanar linear ESF. Implants were removed at the time of radiographic bony union (range, 7–10 weeks; mean, 8.6 weeks). Residual deformity was minimal, ranging from 6° to 15° (mean, 11°). Two minor complications (loosening of 1 pin, serous drainage from 1 pin) resolved with treatment.
Conclusion— Correction of rotational deformity of the pes with intertarsal arthrodesis yielded an excellent clinical outcome, with only a mild residual deformity.
Clinical Relevance— Rotational metatarsal deformities can have a significant impact on gait, ambulation, and appearance. Correction of these deformities and stabilization with ESF and intratarsal arthrodesis can yield an excellent functional outcome, with improved gait and ambulation.     

Radiologic anatomy of the normal appendicular skeleton of the lion (Panthera leo). Part 1: thoracic limb.

Thoracic limb specimens from 12 euthanized free-ranging lions (Panthera leo, 16-170 mo old) underwent radiographic evaluation. The radiographic anatomy was described but excluded any areas of the bones with possible bone pathology. Comparisons between adult and juvenile lions were made and physes described. Differences or similarities (or both) to cheetahs (Acinonyx jubatus) and domestic cats and dogs were also noted. No dissections were made to corroborate the anatomic observations, but comparisons were made to macerated museum specimens. On the basis of evaluation, the scapula has a prominent acromion, hamate, and suprahamate processes, as well as prominent nutrient foramina. The humerus is similar to that of domestic cats. The humeral and ulnar nutrient foramina originate more medially than that in domestic cats. A supracondylar foramen may sometimes be observed radiologically, although one was present on all the macerated specimens in this study. Its radiologic visibility depends on the angle of incidence of the primary beam. The lateral "anconeal tubercle" of the olecranon (situated between the processus anconeus and tuber olecrani) is usually more prominent than the medial one and tends to be hook shaped, pointing cranially. There are no sesamoids in the region of the elbow. The first digit is large with two palmar metacarpophalangeal sesamoids and a prominent sesamoid in the tendon of the M. abductoris digiti I longus, all indications of a high degree of functionality. All physes close before 66 mo of age.     

Correction of angular deformities caused by premature closure of the distal ulnar epiphyseal plate in dogs

Surgical correction of angular deformities caused by premature closure of the distal ulnar growth plate in dogs. Correction of angular deformities in 14 cases of premature closure of the distal ulnar growth plate is described. Angular deformities were most frequently seen in large breeds during the most active phase of growth at 3-5 months of age. Preoperative axial deviations measured on radius were from 7 to 38 degrees in valgus and 0 to 35 degrees in antecurvation compared with the contralateral leg. According to the kind of treatment, the dogs were divided into two groups: In group I which consisted of cases with sufficient remaining growth potential of the radius, segmental ostectomy of ulna with insertion of an autologous fat graft in the ostectomy diastasis was performed to allow spontaneous correction by asymmetrical epiphyseal growth. In group II reconstructive osteotomy and stable, internal fixation with a plate was accomplished. The cosmetic result was judged as excellent in 10 cases, good in 3 and less favourable in 1. Postoperative follow up time was in average 33 months. On control 43% of the dogs showed no lameness, 57% were slightly lame after exercise or rest. None of the cases turned out to be permanently lame at the end of the follow up investigation.     

The surgical treatment of fractures of the olecranon in the horse.

Methods of treating fractures of the olecranon in the horse are reviewed. A further 4 cases are recorded in which the fracture was treated by open reduction and fixation with a heavy duty Venable's plate placed on the caudal aspect of the ulna. Three cases had an oblique fracture through the semilunar notch; this was complicated in one by a fracture of the lateral half of the radial head which resulted in subluxation of the radio-humeral joint. The fracture of the radial head was treated by open reduction and fixation with a lag screw. The fourth case had an oblique fracture of the olecranon just proximal to the semilunar notch, complicated by a fracture of the anconeal process which was removed. The fractures healed within 10 weeks and the plates were removed in all 4 cases. During follow-up periods ranging from 10 to 26 months, all 4 animals became sound.     

In vitro experimental study of the effect of radial shortening and ulnar ostectomy on contact patterns in the elbow joint of dogs

OBJECTIVE: To determine effects of incremental radial shortening and subsequent ulnar ostectomies on joint surface contact patterns in a canine elbow joint model. SAMPLE POPULATION: Paired forelimbs from 9 adult dogs. PROCEDURE: Joint casting was performed by placement of colored polymethylmethacrylate in the elbow joint cavity and loading in a materials testing system at physiologic angle and load. Joint casting was performed in unaltered specimens, after radial shortening, and after subsequent distal ulnar ostectomy, proximal ulnar ostectomy, and proximal ulnar ostectomy with intramedullary pinning. Computer-aided analysis of photographs of proximal radial and ulnar articular surfaces without joint casts was performed before and after each casting procedure. RESULTS: All increments of radial shortening changed the size and location of radial and ulnar contact areas. The radial contact area became smaller, the anconeal contact area disappeared, the medial coronoid contact area migrated craniolaterally, and the lateral projection of the coronoid process became a contact area. A proximal ulnar ostectomy stabilized with an intramedullary pin restored normal contact area size and location and restored continuity of the radial and coronoid contact areas across the radioulnar articulation in 6 of 10 specimens. A midshaft ulnar ostectomy, distal to the level of the radioulnar ligament, had no effect on contact patterns. A proximal ulnar ostectomy without stabilization resulted in varus deformity during loading. CONCLUSIONS AND CLINICAL RELEVANCE: Proximal radial shortening, which creates articular step incongruity, changes the location and size of the radioulnar contact areas. Dynamically stabilized ulnar ostectomies proximal to the radioulnar ligament restore contact patterns in vitro.     

Genetic analysis of three different classification protocols for the evaluation of elbow dysplasia in German shepherd dogs

OBJECTIVES: Three different scoring systems for elbow dysplasia and its radiographic signs were genetically evaluated in 2645 German shepherd dogs. METHODS: An animal model was used to estimate heritabilities and additive genetic and residual correlations for the three scoring systems: ED-SV, which is recommended by the International Elbow Working Group; ED-LA, developed by Lang and others; and ED-TH, proposed by Tellhelm. RESULTS: The effects of sex, age at examination and the correlation between the two factors were significant for all three scoring systems. Heritability estimates (se) were 0.18 (0.04) for ED-SV, 0.11 (0.03) for ED-LA and 0.16 (0.04) for ED-TH. The additive genetic correlations among the different single criteria for elbow dysplasia and the different elbow dysplasia scores were between 0.68 and 0.98, except for the criteria ununited anconeal process and osteochondrosis dissecans of the trochlea humeri, which were mostly genetically negatively correlated to the other radiological criteria. CLINICAL SIGNIFICANCE: The elbow dysplasia scores were determined by two genetically different traits. The possibilities for selecting German shepherd dogs with respect to elbow dysplasia might be improved by taking into account these two traits in the prediction of breeding values.     

Chiari-like malformation in the Griffon Bruxellois

O bjectives : This study describes Chiari-like malformation and syringomyelia in the Griffon Bruxellois and establishes if skull radiographs are useful for disease prediction.
M ethods : Magnetic resonance imaging from 56 Griffon Bruxellois dogs was assessed for Chiari-like malformation and cerebrospinal fluid pathway abnormalities. Skull radiographs were obtained in 33 dogs. Two rostrocaudal and two ventrodorsal measurements were made, and ratios of one length to another were compared.
R esults : In this selected sample, 60·7 per cent had Chiari-like malformation. Syringomyelia occurred with and without Chiari-like malformation (37·5 and 8·9 per cent study population, respectively). The radiographic study demonstrated that one measurement ratio could be used to predict Chiari-like malformation (sensitivity of 87 per cent and specificity of 78 per cent) and that there were significant interaction factors between sex and syringomyelia for two measurement ratios.
C linical S ignificance : The study suggests that Chiari-like malformation is characterised by a shortening of the basicranium and supra-occipital bone with a compensatory lengthening of the cranial vault, especially the parietal bone. We described a simple radiographic technique, which may be useful as a screening test until a more definite genetic test for Chiari-like malformation is available.