Effect of elbow angle and weight‐bearing on the evaluation of joint congruence in dogs

Abstract

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 0 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 < .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 weightbearing, 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.canine elbow dysplasia, degenerative joint disease, elbow morphology, osteoarthritis, radiologic anatomy | INTRODUCTIONElbow dysplasia is a hereditary developmental disorder, leading to degenerative joint disease, and a common cause of thoracic limb lameness in young dogs of medium-to-large breeds (Samoy et al., 2006). Elbow joint geometry has been studied to help unravel the development of incongruency (INC) and its relation to dysplasia,

Humeral intracondylar fissures and intracondylar sclerosis are common CT findings in the limb contralateral to a humeral condylar fracture in French bulldogs and spaniel breeds

“…A limitation of this study is the subjective nature of the assessment of joint incongruency, as dogs were not positioned identically for the CT scan, which made an objective assessment of joint incongruity challenging. 25,26 A recent elbow CT evaluation of non-lame FBD also did not identify elbow incongruency as a feature in their study population. 22 Sclerosis adjacent to the intracondylar fracture site was a common finding in both breed groups.…”

“…Elbow incongruency has been suggested as a potential factor in the development of HIF, 20 but other studies have failed to confirm this theory, 24 which is consistent with the paucity of incongruency observed in this case series. A limitation of this study is the subjective nature of the assessment of joint incongruency, as dogs were not positioned identically for the CT scan, which made an objective assessment of joint incongruity challenging 25,26 . A recent elbow CT evaluation of non‐lame FBD also did not identify elbow incongruency as a feature in their study population 22 …”