Review of the literature

Outcomes of 11 dogs with short radius syndrome treated with acute arthroscopically assisted ulnar shortening

OBJECTIVE

To describe the short-term outcome of acute arthroscopically assisted ulnar shortening (AUS), to treat short radius syndrome in dogs.

STUDY DESIGN

Case series.

ANIMALS

Eleven client owned dogs.

METHODS

Records of dogs that had undergone AUS for treatment of short radius syndrome were reviewed for inclusion. Reporting data included among others pre- and postoperative radioulnar, humeroradial and humeroulnar distances, lameness scores, surgical times, complications and clinical outcome.

RESULTS

Following AUS, radiohumeral articulation was improved in all dogs. Median presurgery radioulnar, humeroradial and humeroulnar values were 4.5, 3.2, and 2.2 mm and were improved with surgery by a median of 3.2, 1.8, and 1.2 mm, respectively. Median surgery time was 140 min. Median time to bone healing was 8 weeks (range: 4-14). Median time to last follow-up was 9 weeks (4-468). Median lameness score (scale 0-4) improved from 2 to 1. No major complications were reported. Short-term clinical outcome was graded by the surgeons as full function in four cases and acceptable function in seven.

CONCLUSION AND CLINICAL RELEVANCE

Radiographic and arthroscopic radiohumeral articulation were improved and short-term clinical improvement was documented following AUS in all 11 dogs.

Long-term outcomes in dogs with elbow dysplasia, assessed using the canine orthopaedic index

BACKGROUND

Elbow dysplasia (ED) is an important cause of lameness in dogs. This study aimed to report long-term outcomes in dogs with elbow osteoarthritis.

METHODS

Demographic data, medical management, and scores from The American College of Veterinary Surgeons' Canine Orthopaedic Index (COI) were collected from owners of dogs radiographically screened for ED, graded as normal, mild, or moderate. Telephone interviews were performed in 2017 (Q1), followed by an email survey in 2020 (Q2). The association between ED grade and deterioration in COI scores over time was evaluated with logistic regression.

RESULTS

A total of 765 replies were collected for Q1 and 293 for Q2. At Q2, 222 dogs (76%) were alive, with a median age of 8 years (range 5-12 years). No association was found between ED and changes in COI score over time or between ED and survival (p = 0.071). Dogs with mild and moderate ED were treated with analgesic medications to a higher degree than dogs without ED (p < 0.05).

LIMITATIONS

Only owner-assed data were assessed; no clinical orthopaedic examination or follow-up radiographic evaluation was performed.

CONCLUSIONS

No association was found between the grade of ED and the worsening of clinical signs in dogs with elbow osteoarthritis.

Comparative evaluation of radiographic and computed tomographic findings in dogs with bilateral medial coronoid disease (MCD) presenting with unilateral forelimb lameness

OBJECTIVES

The purpose of this study was to compare the radiographic and computed tomographic (CT) findings of dogs with diagnosed bilateral medial coronoid disease, which showed clinically only unilateral lameness of the forelimbs.

MATERIALS AND METHODS

Medical records, including radiographs and CT images of dogs with diagnosed bilateral MCD showing only a unilateral forelimb lameness clinically were reviewed retrospectively. Depending on the gait of each dog we established two groups to investigate their radiographs and CT data comparatively. Group I: affected non-lame limb. Group II: affected lame limb. Several evaluation systems were used to assess which factors are important for clinical decision making and a patient tailored therapeutic plan.

RESULTS

Data from 84 affected elbow joints (42 dogs) diagnosed with MCD by computed tomography were included. Both the radiological and the CT analysis showed that there are significant differences between Groups I and II. Group I had a lower modified International Elbow Working Group Score (IEWG), the values of the Trochlear notch sclerosis were only slightly deviated, and this group showed less often a dislocation of the fragment compared to group II. Furthermore, the size of the fragment (both the median and the mean value) of the forelimbs from group II was almost twice as big as the one from group I. The following sizes of the fragments were calculated (group I versus (vs.) group II)-median: 0.09 cm2 vs. 0.16 cm2, mean value: 0.112 cm2 vs. 0.202 cm2. It could be shown that a larger fragment is more likely to dislocate than a smaller one.

CLINICAL SIGNIFICANCE

This study provides some evidence towards a better understanding of which diagnostic parameters and findings might be important in clinical decision making. Nevertheless, a "decision tree" for the correct therapy of MCD could not be determined in this study.

Bone density of the humeral condyle in Labrador retrievers with medial coronoid process disease

OBJECTIVES

To estimate, using CT imaging, differences in the regional bone density of the humeral condyle in Labrador retriever elbows with and without medial coronoid process disease.

MATERIALS AND METHODS

The elbows of Labrador Retrievers that had undergone CT were reviewed. Scans were divided into three categories: elbows without medial coronoid process disease; elbows with medial coronoid process disease involving fragmentation of the radial incisure; elbows with medial coronoid process disease involving fragmentation of the medial coronoid apex. A templating technique was employed to define the weight-bearing regions of the medial and lateral portion of the humeral condyle and estimates of volumetric bone density (defined by Hounsfield unit measurement) were compared across the three groups.

RESULTS

CT evaluation was performed on 122 elbows in 81 dogs. There was a higher mean Hounsfield unit measurement in the medial and lateral portions of the humeral condyles in elbows with medial coronoid process disease involving fragmentation of the medial coronoid apex compared with elbows with medial coronoid process disease involving fragmentation of the radial incisure.

CLINICAL SIGNIFICANCE

Dogs with apical fragmentation of the medial coronoid process exhibited significantly higher estimated bone mineral density within the medial portion of the humeral condyle when compared to dogs with radial incisure fragmentation. The medial portion of the humeral condyle may be associated with the pathogenesis of apical but not radial incisure medial coronoid process fragmentation in Labrador Retrievers.

Effect Of Elbow Angle And Weight-Bearing On The Evaluation Of Joint Congruence In Dogs

Joint congruence is relevant for the assessment of elbow dysplasia, a development disorder in dogs. However, quantification of its variation with joint angle and weight bearing, important factors in quadrupedal locomotion, is lacking. Our objective was to estimate those effects on the alignment of humeroradioulnar joint surfaces. The usual protocol for screening elbow dysplasia, including mediolateral extended and flexed elbow views, was preceded by a weight-bearing lateromedial standing radiographic view, without sedation. Minimum distances were measured at established points of the humeroradioulnar joints classified with a grade zero of dysplasia. Sixty elbows (30 Portuguese Pointer dogs) were studied. The joint space between the anconeal process and the ulnar trochlear notch increased with flexion, decreasing with weight bearing (P<0.001). The distance between the humeral trochlea and the trochlear notch at the widest point, increased with weight bearing, while it decreased with flexion. Step and distance between the radial head and the base of the medial coronoid process increased with flexion and decreased with weight bearing. At this point, physiological changes occurred at the humeroulnar joint space. The methodology allowed to quantify the variations on joint spaces with the elbow angle and weight bearing, important for the interpretation of congruence in diagnosis and treatment of dysplasia. Reference absolute and indexed values obtained allow future comparisons with other breeds and dysplastic dogs. Physiological variations denoted that radioulnar joint became more incongruent under flexion, and more congruent under weight bearing, while humeroulnar joint became more congruent under flexion, and more incongruent under weight bearing.

Relation of Computed Tomography-Based Static Axial Radioulnar Incongruence Measurements under General Anaesthesia and Dynamic, In Vivo RUI during the Walk in Canine Elbow Joints with and without Medial Coronoid Process Disease

OBJECTIVE

 This study aimed to evaluate the correlation of static axial radioulnar incongruence (sRUI) measured under general anaesthesia with the real in vivo dynamic RUI (dRUI) during walking.

STUDY DESIGN

 This was a prospective clinical study that included 6 sound elbows (5 dogs) and 7 medial coronoid process disease (MCPD) affected elbows (6 dogs).

MATERIALS AND METHODS

 Static axial radioulnar incongruence was measured using the sphere fitting technique on computed tomography-based three-dimensional (3D) models of radius and ulna. The in vivo pose of radius and ulna was derived from radiostereometric analysis during the walk and transferred onto previously calculated 3D models. Dynamic RUI was measured on those adjusted models using the sphere fitting technique, providing a measurement of RUI over time during walk.

RESULTS

 Mean sRUI was 0.2 mm (standard deviation [SD]: 0.30) in control and 1.4 mm (SD: 0.73) in elbow joints with MCPD; being significantly different (p = 0.0035; confidence interval [CI]: 0.4772-1.8824). Mean dRUI in controls (-0.4 mm; SD: 0.47) was significantly different (p = 0.0004; CI: 0.9918-2.5225) from dRUI in the affected elbows (1.4 mm; SD: 0.73). Comparison of sRUI and dRUI within each group showed difference in the control group (0.2 vs. -0.4 mm; p = 0.0138; CI: 0.1820-1.0014). In affected elbows, no difference between sRUI and dRUI was found (1.4 vs. 1.4 mm; p = 0.8963).

CONCLUSION

 In normal elbow joints, sRUI does not represent the in vivo condition during weight bearing. Dynamic and slightly negative RUI occurs during loading (0.2 mm positive to -0.4 mm negative RUI). In MCPD affected elbows with sRUI, no dynamic change of RUI occurs during the walk.

Canine Elbow Dysplasia: Ununited Anconeal Process, Osteochondritis Dissecans, and Medial Coronoid Process Disease

Elbow dysplasia is a major cause of front limb lameness in medium to large dog breeds. Underlying causes include ununited anconeal process, medial coronoid process disease, and osteochondritis dissecans. When a definitive diagnosis of elbow dysplasia is made, the surgeon can improve elbow function but cannot entirely prevent progression of osteoarthrosis. Conventional surgical treatment with joint debridement and removal of loose osteocartilaginous bodies is not rewarding if joint incongruity persists; the result is overloading and subchondral bone exposure with erosion of the cartilage of the medial humeral condyle and medial coronoid area of the ulna leading to medial compartment disease.

Long-Term Prognosis of Quality of Life in Dogs Diagnosed With Mild to Moderate Elbow Dysplasia in Sweden

Objective: The objective of this study was to increase knowledge regarding long-term prognosis of mild to moderate elbow dysplasia (ED) using a canine orthopedic index.

Study Design: Cross-sectional observational study.

Sample Population: Sixty dogs randomly selected from each of five different breeds and three ED groups: ED0 (control), ED1, and ED2, based on the Kennel Club's screening results. The total number of selected dogs was 900 (60^*5^*3).

Methods: Questionnaires were administered to owners by telephone interview. Bayesian network modeling was used to assess the relation between ED grade, treatment options, dog demographics, and quality-of-life indicators.

Results: Seven hundred sixty-five questionnaires were collected (85% response rate), of which 61 concerned dogs euthanized due to osteoarthritis. There was no direct association between ED grade and owner's perceived quality of life, but ED1 and ED2 dogs were more likely to receive veterinary care and subsequent NSAID treatment compared to ED0 dogs. A significant association was found between the occurrence of euthanasia due to orthopedic disease and ED scores 1 and 2 in the sample (p < 0.001).

Conclusion: The degree of osteoarthritis was not directly associated with the canine orthopedic index, except for ED2 and lameness score. It can be speculated that owners who paid closer attention to orthopedic symptoms and perceived them as impairing their dogs' lives were also more likely to seek veterinary care and get treatment, irrespective of the ED grading.

Impact: ED1-graded dogs had a lower risk than might be expected to develop visible clinical symptoms and showed a similar quality of life as dogs with ED0. ED2-graded dogs were more likely than ED0-graded dogs to have their lives impaired by lameness, according to the owners' perception.

Computed tomographic findings in three Pinschers affected by incomplete ossification of the humeral condyle

Incomplete ossification of the humeral condyle is a cause of forelimb lameness in dogs. Affected dogs are predisposed to humeral condylar fractures. Incomplete ossification of the humeral condyle has been reported in breeds such as Spaniel, Rottweiler, Labrador and Pug. Diagnosis is made by a radiographic or computed tomographic study of the elbow, while treatment includes the placement of a bone screw across the humeral condyle. This paper discusses the computed tomography findings of incomplete ossification of the humeral condyle in three Pinschers.

Radiographic determination of humeroradial, humeroulnar, and radioulnar subluxation indices to quantify elbow incongruence in dogs confirmed to have medial coronoid disease

Medial coronoid disease and elbow incongruence are common orthopedic problems causing forelimb lameness in large breed dogs. Therefore, the objective of this retrospective clinical study is to radiographically quantify the incongruity of humeroradial, humeroulnar, and radioulnar joints in dogs with confirmed medial coronoid disease compared to controls. Sixty-six (93 elbows) control and 73 (113 elbows) diseased Labrador and Golden Retrievers were enrolled. Our objective was achieved by measuring the central humeroradial, humeroulnar, and radioulnar distances and calculating the corresponding subluxation index of each joint on the extended mediolateral elbow radiograph. The traditional radioulnar step was also measured on the same mediolateral projection. Variables were compared between control and diseased groups, and the significance level was P < .05. The central humeroradial, humeroulnar, and radioulnar distances and corresponding subluxation indices increased significantly (P ≤ .007) in elbows with confirmed medial coronoid disease compared to controls. Radioulnar step increased significantly (P < .0001) in diseased elbows. Elbow incongruence, manifested by increased humeroradial, humeroulnar, and radioulnar subluxation indices, appeared to be consistent with medial coronoid disease in Labrador and Golden Retrievers. An elbow with a humeroradial, humeroulnar, or radioulnar subluxation index >0.15, 0.10, or 0.14, respectively, or radioulnar step >1.4 mm, is more likely to be incongruent and may have a concomitant coronoid disease. However, future validation of the reported measurements is still warranted.

Radial torsion in dogs with medial compartment disease

OBJECTIVE

To evaluate the magnitude and direction of radial torsion (RT) in dogs with medial compartment disease (MCD).

STUDY DESIGN

Case-control study.

SAMPLE POPULATION

Twenty-eight healthy dogs and 28 dogs with confirmed MCD.

METHODS

Computed tomography images of each dog's antebrachium were evaluated. Radial torsion was measured by using previously described landmarks on the proximal and distal radius. Differences between groups were tested with Student's t tests and Wilcoxon rank-sum tests.

RESULTS

Healthy dogs had a mean RT angle of 3.44° (range, 1.28°-5.44°). Dogs with MCD had a mean RT angle of 11.84° (range, 2.31°-26.55°). Both groups included similar proportions of dogs with external (76% vs 77%) and internal (24% vs 23%) torsion. The direction of torsion (P = .21 and P = .69) did not appear to affect the magnitude of the RT angle.

CONCLUSION

Dogs with MCD had an increased RT angle compared with healthy controls. The direction of torsion varied similarly between groups regardless of the disease status of dogs in this study.

CLINICAL SIGNIFICANCE

The fourfold increase in the RT seen in dogs with MCD may contribute to the rotational overload proposed recently, potentially modifying the orientation of the elliptical radial head and the ligaments crossing the elbow joint.

Computerized measurements of radiographic anatomical parameters of the elbow joint in Bernese Mountain Dogs

Objective: Comparison of two methods for evaluation of anatomical parameters of elbow joints in Bernese Mountain Dogs.

Study design: Radiographic analysis.

Animals: Nine hundred and thirty-one radiographs of elbow joints from 305 Bernese Mountain Dogs.

Material and methods: The angles OL, PA, RA and UL were measured according to the Mues method and the Radius of the humeral condyle, Opening angle beta, Quotient Q and Ae, Area X, Step 1 and Step 2 according to the Viehmann method. The radiographs were divided according to their angle of flexion into five groups: 0–30°, 31–60°, 61–90°, 91–120° and >120°. The difference and the correlation between measured values and the elbow dysplasia (ED) score was calculated and compared.

Results: The average values of angle OL, PA and RA, Area X, Step 1 and Step 2 were significantly different within the different elbow flexion angle groups. The values of Opening angle beta, Quotients Q and Ae as well as Radius of the humeral condyle varied independently from the degree of the elbow flexion on the radiograph. The angles OL, PA and RA and the Radius of the humeral condyle, the Opening angle beta, the Quotients Q and Ae, Step 1 and Step 2 correlated with the ED score.

Conclusion: In contrast to the method of Mues, the majority of the measured parameters of the method of Viehmann were not influenced by the degree of flexion of the elbow joint and correlated with the ED score. Clinical relevance: The method of Viehmann warrants consideration for the evaluation of radiographs of elbow joints in the Bernese Mountain Dog for ED.

This article is based on a study first reported in S. Stein's doctoral thesis, which was presented on 08.05.2007 and published thereafter in full by Mensch & Buch Verlag. This abridged and translated version is now being published with the kind permission of Mensch & Buch Verlag.

Analysis of risk factors for elbow dysplasia in giant breed dogs

Objective: Identify radiographic risk factors for development of elbow dysplasia in giant breed dogs less than one year of age.

Methods: Twenty-five giant breed puppies (Bernese Mountain dogs, English Mastiff, and Newfoundland) were studied. Both elbows of each dog were radiographed monthly from two to six months of age, then every other month until radial and ulnar physeal closure, followed two months later by bilateral elbow computed tomography. Radiographic parameters measured included the presence or absence of a separate centre of ossification of the anconeal process (SCOAP), medial coronoid disease (MCD), ununited anconeal process, humeral osteochondrosis, elbow incongruity, as well as the length of the radius and ulna, radius-to-ulna ratio, and date of closure of the radial and ulnar physes.

Results: Fifteen dogs completed the study. Two Bernese Mountain dogs were diagnosed with MCD. Risk factors significantly associated with medial coronoid disease included dyssynchronous physeal closure and a decreased radius-to-ulna ratio, both detected between eight to 11 months of age. A separate centre of ossification of the anconeal process was present in 60% of the dogs, and was not a risk factor for development of elbow dysplasia.

Clinical significance: Transient, dyssynchronous growth of the radius and ulna may be a risk factor for development of MCD in Bernese Mountain dogs. Dyssynchronous physeal closure or decreased radius-to-ulna ratio prior to radiographic closure of the distal ulnar and radial physes warrants further study in Bernese Mountain dogs and other breeds subject to MCD development.

Avaliação morfológica e morfométrica da articulação umerorradioulnar em cães através de exames radiográficos e por tomografia computadorizada

RESUMO: Este estudo teve como objetivo apresentar de forma detalhada dados morfológicos e morfométricos da articulação umerorradioulnar de cães de raça definida avaliados por meio de exames físicos, radiográficos e tomográficos. A amostra dessa pesquisa constituiu-se de 44 cotovelos de cães com idades variadas. Para análise de informações obtidas, o coeficiente kappa e de correlação interclasse e associação foram realizados. Constatou-se que o desempenho individual de cada projeção radiográfica teve pobre concordância com o exame tomográfico; não houve concordância entre os observadores para as mensurações do ângulo da incisura ulnar ao exame radiográfico e tomográfico. Porém houve boa/moderada concordância para mensuração da incongruência radioulnar no plano sagital entre os observadores. Concluiu-se que nenhuma das cinco incidências radiográficas foi superior para análise radiográfica, uma vez que cada projeção apresentou melhor identificação de um compartimento do cotovelo. Medidas ao exame tomográfico para incongruência radioulnar não apresentaram reprodutibilidade no plano de reconstrução frontal, entretanto no corte sagital apresentaram boa e moderada concordância entre os observadores e que a mensuração do ângulo da incisura ulnar não apresentou repetibilidade ao exame radiográfico e nem reprodutibilidade ao exame tomográfico. Esses resultados contribuem para melhor utilização de cada exame de acordo com a região a ser avaliada bem como ressaltam a necessidade da somatória de múltiplos exames de imagem para a correta avaliação desta afecção.

COMPUTED TOMOGRAPHIC FINDINGS IN CANINE ELBOWS ARTHROSCOPICALLY DIAGNOSED WITH EROSION OF THE MEDIAL COMPARTMENT: AN ANALYTICAL METHOD COMPARISON STUDY

Medial compartment erosion is an advanced stage of medial coronoid disease, an important cause of elbow lameness in dogs, with treatment and the expected prognosis depending on the extent of the cartilage lesions. The identification of specific computed tomographic (CT) findings might facilitate the nonsurgical diagnosis and add to treatment decision making. Aims of this retrospective, analytical, method comparison study were to describe CT findings in elbows of dogs arthroscopically diagnosed with medial compartment erosion and to compare CT vs. arthroscopic findings. A total of 56 elbows met inclusion criteria. Elbows with focal (n = 13), diffuse (n = 11), and complete (n = 32) erosion were compared. Prevalence findings for CT lesions were as follows: periarticular osteophytosis (100%), abnormal shape of the medial coronoid process of the ulna (96.4%), and subchondral bone defect of the medial part of the humeral condyle (MHC; 96.4%). The three groups significantly differed for presence of medial coronoid process fragmentation, radial head subchondral bone sclerosis, and widening of the humeroulnar joint space. No significant agreement was found between CT and arthroscopy for presence of a subchondral bone defect of the MHC. A significant agreement was found between CT and arthroscopy for presence of fragmentation of the medial coronoid process. However, some of the calcified body/fragment(s) visualized on CT in the region of the medial coronoid process could not be identified via arthroscopy. Findings indicated that an accurate estimation of the extent of the elbow cartilage lesions still requires arthroscopic joint inspection.

Assessment of medial coronoid disease in 180 canine lame elbow joints: a sensitivity and specificity comparison of radiographic, computed tomographic and arthroscopic findings

Background

Diagnostic imaging is essential to assess the lame patient; lesions of the elbow joint have traditionally been evaluated radiographically, however computed tomography (CT) has been suggested as a useful technique to diagnose various elbow pathologies. The primary objective of this study was to determine the sensitivity and specificity of CT to assess medial coronoid disease (MCD), using arthroscopy as gold standard. The secondary objective was to ascertain the radiographic sensitivity and specificity for MCD compared with CT.

Methods

For this study 180 elbow joints were assessed, of which 141 had been examined with radiography, CT and arthroscopy; and 39 joints, had radiographic and CT assessment. Sensitivity and specificity were calculated for CT and radiographic findings using available statistical software.

Results

Sensitivity and specificity of CT using arthroscopy as gold standard resulted in high values for sensitivity (100 %) and specificity (93 %) for the assessment of MCD. For the radiographic evaluation, a sensitivity of 98 % and specificity of 64 - 69 % using CT as the technique of reference, were found.

Discussion

These results suggest that in case of doubt during radiographic assessment, CT could be used as a non-invasive technique to assess the presence of MCD.

Conclusion

Based on the high sensitivity and specificity obtained in this study it has been considered that CT, rather than arthroscopy, is the preferred noninvasive technique to assess MCD lesions of the canine elbow joint.

Medical Infrared Imaging of Normal and Dysplastic Elbows in Dogs

OBJECTIVE

To investigate the ability of medical infrared imaging to differentiate between normal canine elbows and those with abnormal elbows (elbow dysplasia).

STUDY DESIGN

Prospective cohort study.

ANIMALS

Dogs with normal (n = 15) and abnormal (n = 14) elbows.

METHODS

Infrared imaging was performed on all dogs and data analyzed via descriptive statistics and image pattern analysis software. Animals with elbow dysplasia had arthroscopic procedures to confirm the presence of elbow disease.

RESULTS

Computer recognition pattern analysis was up to 100% correct in identifying abnormal elbows and normal elbows, with the medial images most consistent. The caudal, lateral, and cranial images correctly identified 83-100% abnormal elbows. The caudal and lateral images correctly identified 83% normal elbows. A significant difference in temperature was found between normal and abnormal elbows for the cranial full region of interest, lateral images, and each quadrant.

CONCLUSION

Medical infrared imaging was able to correctly identify known abnormal and known normal elbows in dogs.

Focal humero-ulnar impingement following subtotal coronoid ostectomy in six dogs with fragmented medial coronoid process

OBJECTIVE

To report acute eburnation of joint cartilage at the humeral trochlea following subtotal coronoid ostectomy (SCO) in a clinical case series of six elbows.

MATERIAL AND METHODS

Six dogs (median BW 27.1 kg; median age 7.5 months) with fragmented medial coronoid process (FCP) and varying degree of radio-ulnar incongruence (RUI) (mean 2 mm) were treated with SCO using an arthroscopic burr. Second look arthroscopy 4-12 weeks later was performed either because of recurrent or persistent lameness in three dogs. In the others, second-look arthroscopy was scheduled prospectively because of RUI, which was thought to be a risk factor for the observed humero-ulnar impingement.

RESULTS

All six elbows had a 1-2 mm wide line of focal full-thickness cartilage loss along the edge of the SCO, while the opposing trochlea had diffuse cartilage damage of Outerbridge grade III-IV, indicating focal humero-ulnar impingement. None of the elbows showed repeated FCP.

CONCLUSION

In some cases SCO might lead to focal humero-ulnar impingement along the osteotomy line.

CLINICAL SIGNIFICANCE

Whether this relays to variations in respect the amount of resected bone (too much vs. too less) or concomitant joint pathologies like RUI or joint instability remains unknown and warrants further studies.

Topographic bone density of the radius and ulna in greyhounds and labrador retrievers with and without medial coronoid process disease

OBJECTIVE

To quantify, using computed tomography (CT), cross-sectional ulnar bone density (UBD), and regional radial bone density (RRBD) at the level of the medial coronoid process (MCP) in elbows with and without medial coronoid process disease (MCPD) and with and without fragmentation of MCP (FCP).

STUDY DESIGN

Retrospective clinical case-control and ex vivo study.

SAMPLE POPULATION

Labrador Retriever elbows (n = 54) and normal cadaveric Greyhound elbows (11) undergoing elbow CT.

MATERIALS AND METHODS

Labrador Retriever elbows were divided into 2 groups: (1) clinically unaffected and (2) MCPD-affected elbows. This 2nd group was subdivided based on the presence of a displaced FCP. UBD was measured linearly, in Hounsfield units (HU) across the widest part of the ulna incorporating the MCP. The radial head was divided into 6 zones, with mean RRBD (HU) calculated for each group.

RESULTS

MCPD-affected Labrador Retriever elbows had significantly lower UBD within the MCP with a higher UBD in the cranial ulnar medulla. Lower RRBD was also seen in the radial head adjacent to the MCP in MCPD-affected Labrador Retriever elbows with FCP compared with Labrador Retriever elbows without FCP. Greyhounds had consistently lower RRBD and UBD at the apex of the MCP compared with clinically unaffected Labrador Retriever elbows.

CONCLUSIONS

Our results suggest a caudolateral load-transfer shift through the ulna in MCPD-affected elbow joints, unloading the MCP. Changes in regional radial head bone density suggest that the radial head is involved in the pathogenesis of MCPD.

Efficacy of an oral hyaluronate and collagen supplement as a preventive treatment of elbow dysplasia

One hundred and five Labrador dogs were randomly divided into two groups to determine the number of animals that develop elbow dysplasia when treated with an oral supplement compared to untreated ones. Efficacy of the oral treatment was also evaluated once illness was diagnosed. The supplement (Hyaloral) contained hyaluronic acid, hydrolysed collagen, glucosamine, chondroitin sulphate, and gamma oryzanol. Clinical evaluation of the elbow joints was completed at months 3, 6, 12, and 20 by orthopaedic evaluations, radiography, serologic and blood analysis, and veterinarian evaluation of dysplasia symptoms. All side effects were recorded. In the control group, 33.3% of the dogs developed radiographic evidence of elbow dysplasia compared to 18.5% in the treated group. Symptoms of dysplasia at 12 months differed between the treated (12.5%) and control (61.5%) animals, and were significantly different at 20 months (p < 0.05). Differences in lameness along with movement and swelling of the elbows between groups were observed after 12 months. The treated group had improved significantly by the last visit (p < 0.05). No adverse side effects were reported. In conclusion, oral treatment with Hyaloral may have a potential cumulative action that provides protection against dysplasia and significantly improves symptoms of elbow dysplasia.

Correlation between histopathologic, arthroscopic, and magnetic resonance imaging findings in dogs with medial coronoid disease

OBJECTIVE

To describe the magnetic resonance imaging (MRI), arthroscopic, and histopathologic changes in dogs with medial coronoid disease and to identify potential relationships between these findings.

STUDY DESIGN

Retrospective case series.

SAMPLE POPULATION

Twenty-five diseased medial coronoid processes (MCP) were collected from 19 dogs with a confirmed diagnosis of medial coronoid disease that were surgically treated by subtotal coronoid ostectomy. A reference group of normal MCP was collected from 9 dogs euthanatized for reasons unrelated to elbow disease.

METHODS

MCP specimens were evaluated by MRI using a novel grading scheme (all dogs), arthroscopy using a modified Outerbridge scheme (affected dogs only) and histopathology (all dogs).

RESULTS

The common histopathologic findings were subchondral microfractures, subchondral microfractures continuous with cartilaginous fissures, moderate to severe hypercellularity of the marrow space, trabecular bone necrosis, and articular cartilage degeneration. The severity of cartilage disease in the MCP was moderate to severe in most specimens, even in cases with minimal arthroscopic pathology. Three distinct patterns of bone marrow lesion (BML) were identified adjacent to the MCP, but there was no correlation between BML pattern and either histopathologic or arthroscopic findings. There was moderate correlation between modified Outerbridge scores and MRI scores. No correlation was identified between the histopathologic changes and either MRI or arthroscopic scores.

CONCLUSION

There was no significant correlation between the clinical scores and histopathologic changes. Ongoing improvements in the resolution of noninvasive imaging techniques will likely improve description and understanding of the MCP disease in dogs.

Short- and long-term outcomes after arthroscopic treatment of young large breed dogs with medial compartment disease of the elbow

OBJECTIVES

To report short- and long-term outcomes after arthroscopic treatment in young large breed dogs affected by medial coronoid process disease (MCPD) and identify variables affecting outcome.

STUDY DESIGN

Prospective observational case series.

ANIMALS

Large breed dogs <3 years old (n = 15; 23 elbows).

METHODS

MCPD was confirmed by radiography, computed tomography, and arthroscopy. Dogs were treated by arthroscopy. Variables recorded at time of treatment included radioulnar incongruity (RUI) and degree of cartilage erosion. Variables recorded before, 6 weeks, and ≥23 months after surgery included radiographic score for osteoarthritis, trochlear notch sclerosis, muscle circumference, range of motion (ROM), and the load distribution of vertical ground reaction forces between thoracic and pelvic limbs.

RESULTS

A greater load distribution to the pelvic limbs was identified preoperatively in dogs with RUI than in dogs with congruent elbows. Load distribution was not significantly improved at 6 weeks compared with preoperatively. Muscle circumference and vertical impulse distributions were improved at long-term evaluation despite an increased osteoarthritis score. This improvement was more obvious in dogs with RUI or a high degree of cartilage erosion at initial presentation.

CONCLUSION

Some evidence of improvement in long-term function was found in dogs with MCPD after arthroscopic treatment. RUI and cartilage erosion at the time of diagnosis were associated with more lameness preoperatively but did not affect the final gait assessment or osteoarthritis score in this small cohort.

CT assessment of the influence of dynamic loading on physiological incongruency of the canine elbow

OBJECTIVES

To present a novel technique for loading of the canine elbow joint and to quantify changes in congruency with increasing load using computed tomography.

MATERIALS AND METHODS

Five pairs of thoracic limbs were mounted at a mid stance angle in a custom made jig. Elbow joints were loaded to 0, 33, 66 and 100% of total individual cadaver bodyweight. At each load computed tomography of the elbow was performed. Joint space measurement was performed on sagittal plane central, lateral and medial compartment images at humero-radial (R1 , R2 , R3 ), humero-ulnar (U1 , U2 ) and radio-ulnar loci. The effect of loading on joint spaces was assessed (P<0.05).

RESULTS

With increasing load; for central an increase in R1 and radio-ulnar distance and decreased R3  occurred; for medial R1 increased; and for lateral R1 and radio-ulnar distance increased. The largest increases were seen in the lateral compartment.

CLINICAL SIGNIFICANCE

Significant changes in humero-radio-ulnar congruency occurred suggesting pronation of the radius with respect to the ulna was induced during loading. This movement may influence the load experienced by the medial coronoid process and could play a role in the aetiopathogenesis of medial coronoid process disease.

Monitoring Hip and Elbow Dysplasia achieved modest genetic improvement of 74 dog breeds over 40 years in USA

Hip (HD) and Elbow Dysplasia (ED) are two common complex developmental disorders of dogs. In order to decrease their prevalence and severity, the Orthopedic Foundation for Animals (OFA) has a voluntary registry of canine hip and elbow conformation certified by boarded radiologists. However, the voluntarily reports have been severely biased against exposing dogs with problems, especially at beginning period. Fluctuated by additional influential factors such as age, the published raw scores barely showed trends of improvement. In this study, we used multiple-trait mixed model to simultaneously adjust these factors and incorporate pedigree to derive Estimated Breeding Values (EBV). A total of 1,264,422 dogs from 74 breeds were evaluated for EBVs from 760,455 hip scores and 135,409 elbow scores. These EBVs have substantially recovered the reporting bias and the other influences. Clear and steady trends of genetic improvement were observed over the 40 years since 1970. The total genetic improvements were 16.4% and 1.1% of the phenotypic standard deviation for HD and ED, respectively. The incidences of dysplasia were 0.83% and 2.08%, and the heritabilities were estimated as 0.22 and 0.17 for hip and elbow scores, respectively. The genetic correlation between them was 0.12. We conclude that EBV is more effective than reporting raw phenotype. The weak genetic correlation suggested that selection based on hip scores would also slightly improve elbow scores but it is necessary to allocate effort toward improvement of elbow scores alone.

Anatomical study of fibrous structures of the medial aspect of the canine elbow joint

Forces exerted by fibrous structures on the medial aspect of the canine elbow joint have been reported to be involved in elbow pathology. The purpose of this paper is to assess the relationships of the ligamentous and muscular structures of this region of the canine elbow joint, and how they relate to the medial coronoid process. Six cadavers of adult German shepherd cross-breed dogs were used in this study to make intra-articular and vascular injections of this region. Some joints were dissected and some were frozen to saw sagittal or dorsal cryosections to assess the relationships of the myotendinous structures. The brachialis muscle tendon passed through the division of the bicipital tendon of insertion which formed a fibrous tendon sheath that was reinforced by the oblique ligament. The biceps' brachii's main insertion is the radial tuberosity where it inserts along with the cranial branch of the oblique ligament and the cranial branch of the medial collateral ligament. Rotational and compression forces exerted by the insertion of the biceps brachii-brachialis tendon complex onto the ulna might influence medial coronoid disease. Therefore, sectioning these tendons could be considered as a treatment for medial coronoid disease.

Arthroscopic treatment of fragmented coronoid process with severe elbow incongruity. Long-term follow-up in eight Bernese Mountain Dogs

The purpose of this study was to investigate the long-term treatment results of fragmented coronoid process (FCP) in joints with a radio-ulnar step greater than 3 mm. Treatment of these patients only consisted of fragment removal, without correction of the incongruity. The eight Bernese Mountain Dogs (11 joints) included in this study showed obvious clinical signs of elbow disease and were diagnosed with severe elbow incongruity and concomitant FCP in the time period from 1999-2003. At that time, elbow radiography, computed tomography, and arthroscopy were performed. The mean follow-up period was 5.6 years. The follow-up consisted of a telephone questionnaire combined with a clinical and radiographic re-evaluation at our clinic. The questionnaire revealed that all dogs were either free of lameness or only lame following heavy exercise. One dog sporadically required medication after heavy exercise. The owner satisfaction rate was 100%. The clinical re-evaluation did not reveal any signs of pain or lameness in all cases. Range-of- motion was decreased in nine of the 11 elbows. Radiographs revealed an increase in severity of osteoarthritis in every case.In this case series, arthroscopic fragment removal without treatment of incongruity was demonstrated to be a valuable treatment option and may provide a satisfactory long-term outcome.

Computed tomography of ununited anconeal process in the dog

OBJECTIVE

The purpose of this study was to describe computed tomography (CT) features of the ununited anconeal process and relate them with the following elbow dysplasia signs: medial coronoid disease, medial humeral condyle changes, osteoarthritis (OA), and radioulnar incongruence.

METHODS

Computed tomographic images of dogs older than six months with an ununited anconeal process were evaluated (n = 13). Ununited anconeal process features were described as being complete or incomplete, and the degree of displacement, volume, and presence of cysts and sclerosis were also evaluated. Medial coronoid disease was defined as an irregular medial coronoid process shape, presence of sclerosis and fragmentation. Medial humeral condyle changes were defined as subchondral bone flattening, lucencies, and sclerosis. Osteoarthritis was graded depending on the osteophytes size. Radioulnar incongruence was measured on a sagittal view at the base of the medial coronoid process.

RESULTS

Eleven elbows had a complete and two had an incomplete ununited anconeal process. All ununited anconeal processes had cystic and sclerotic lesions. Seven ununited anconeal processes were displaced and six were non-displaced. Mean ununited anconeal process volume was 1.35 cm3 (0.61 cm³ - 2.08 cm³). Twelve elbows had signs of medial coronoid disease (4 of them with a fragmented medial coronoid process), and one elbow did not show any evidence of medial coronoid disease. Ten elbows had medial humeral condyle changes. One elbow had grade 1 OA, seven elbows had grade 2, and five elbows grade 3. All elbows had radioulnar incongruence: three elbows had a negative and 10 elbows had a positive radioulnar incongruence. Mean radioulnar incongruence was 1.49 mm (0.63 mm - 2.61 mm). Computed tomographic findings were similar in the majority of the elbows studied: complete ununited anconeal processes with signs of medial coronoid disease, positive radioulnar incongruence, high grade of OA, sclerotic medial humeral condyle changes, and large ununited anconeal process volumes.

CLINICAL SIGNIFICANCE

Incomplete small ununited anconeal process volumes could be associated with a lower incidence of medial coronoid disease or medial humeral condyle changes. We recommend performing preoperative CT of elbows with an ununited anconeal process to evaluate concurrent lesions.

Quantification of humeroulnar incongruity in labrador retrievers with and without medial coronoid disease

OBJECTIVE

To quantify humeroulnar incongruity on elbow radiographs in Labrador Retrievers with or without medial coronoid disease (MCD).

STUDY DESIGN

Retrospective study of 92 elbows.

SAMPLE POPULATION

Radiographic projections of elbow joints from Labrador Retrievers with MCD (n = 42 elbows; 26 dogs) and without MCD (n = 50 elbows; 25 dogs).

PROCEDURE

The congruity of the humeroulnar joint was measured using an index of subluxation (SI) for each elbow. SI was defined as the distance between the centers of 2 circles drawn along the margins of the incisura trochlearis and the trochlea of humerus on mediolateral digital radiographic projections, normalized by the radius of the circle circumscribing the humeral trochlea. SI was compared between right and left elbows with and without pathology using a Wilcoxon test for paired data, and between normal and abnormal groups with a Wilcoxon test for unpaired data. Mismatch between ulnar curvature and curvature of humeral trochlea and radioulnar incongruency were also noted (Wilcoxon test). The intraobserver repeatability, correlation between SI and radioulnar incongruency, and between SI and mismatch elbow curvature were estimated with a Pearson's correlation coefficient.

RESULTS

Intraobserver repeatability of SI measurement was high (r = 0.97). Mean ± SD humeroulnar incongruity (SI) was greater in elbows with MCD (18.5 ± 6.6) than in the normal elbows (1.7 ± 2.0, P < 0.001). The difference between the diameters of the curvatures of the ulnar and humeral trochlea was greater in elbows with MCD (12.5 ± 4.4) than in the normal group (10.7 ± 4.1, P < 0.05). A moderate correlation was found between the degree of humeroulnar incongruity and a radioulnar step (r = 0.63); however, no correlation was identified between SI and the difference between the diameters of the curvatures of the ulnar and humeral trochleae (r = 0.14).

CONCLUSION

We propose a radiographic index to measure humeroulnar incongruity on mediolateral digital radiographic projections. This index (SI) supports the presence of humeroulnar incongruity in Labrador Retrievers with MCD. Further evaluation of its reproducibility and clinical importance are warranted. Although there is a moderate correlation between humeroulnar incongruity and radioulnar incongruency, causation has not been established.

Radiographic evaluation of osteotomized ulnar segments following arthroscopic treatment for canine medial coronoid disease

OBJECTIVE

To assess movement of ulnar segments radiographically, following proximal and midshaft ulnar osteotomy or ostectomy after arthroscopic treatment for dogs diagnosed with medial coronoid disease.

METHODS

Fragmentation and cartilage wear were treated arthroscopically and the presence of incongruity confirmed. Osteotomies were performed at the mid-point or proximal third of the length of the ulna. The distance of separation between the ulnar segments and the adjacent radius were measured and followed by serial radiographs postoperatively until healing had occurred.

RESULTS

Proximal oblique osteotomies located at one-third the length of the ulna were associated with the most movement of the ulnar segments, most notably of the proximal segment. Osteotomies or ostectomies performed in the middle demonstrated less segmental movement and on average, slightly longer time to heal. Movement of the ulnar segments in both groups occurred immediately, and then peaked at two to four weeks postoperatively, tending to plateau thereafter.

CLINICAL SIGNIFICANCE

Radioulnar incongruity is considered a facet of the aetiopathogenesis of canine medial coronoid disease. This creates abnormal loads and focal wear along the medial coronoid process. Performing an oblique osteotomy at a location measured at the proximal third of the length of the ulna allows increased movement of the proximal segment, which may result in unloading of the medial compartment. Performing an osteotomy or ostectomy distally dampens segmental movement due to constraint of the interosseous ligament. These findings suggest that a proximal oblique osteotomy at this location creates immediate favourable movement with low morbidity.