Variation in position of the medial fabella in West Highland white terriers and other dogs

• Published in: Journal of small animal practice Vol. 50; no. 5; pp. 236 - 240
• Main Authors: Störk, C.K, Petite, A.F, Norrie, R.A, Polton, G.A, Rayward, R.M
• Format: Journal Article
• Language: English
• Published: Oxford, UK Oxford, UK : Blackwell Publishing Ltd 01-05-2009; Blackwell Publishing Ltd
• Subjects: abnormal development; Animals; Anterior Cruciate Ligament - diagnostic imaging; Body Size; body weight; breed differences; Cohort Studies; Dog Diseases - diagnostic imaging; Dog Diseases - epidemiology; Dogs; Female; joint diseases; Knee Joint - diagnostic imaging; ligaments; Male; medial fabella; patella; Patellar Dislocation - diagnostic imaging; Patellar Dislocation - epidemiology; Patellar Dislocation - veterinary; Prevalence; Radiography; risk factors; sesamoid bones; Sesamoid Bones - diagnostic imaging; stifle; Stifle - diagnostic imaging; terriers; West Highland White Terrier (dog breed)
• ISSN: 0022-4510; 1748-5827
• DOI: 10.1111/j.1748-5827.2009.00746.x

To investigate whether West Highland white terriers exhibit significant variation in the position of the medial fabella compared to both small and large breed dogs. Criteria for the normal location of the medial fabella on a caudocranial radiograph were established. A retrospective analysis was undertaken of a consecutive series of bilateral caudocranial stifle joint radiographs from 70 West Highland white terriers, 100 small and 100 large control dogs by three reviewers. Medial fabellar location, cruciate ligament disease and medial patellar luxation were examined within and between groups. Abnormal medial fabellar location was identified in 70 per cent, 9 per cent and 0 per cent of West Highland white terriers, small dogs and large dogs, respectively. In the vast majority of the affected dogs, the fabella was found in a mediodistal location. Presence of concurrent cranial cruciate ligament disease or medial patellar luxation and body weight was excluded as confounding factors. West Highland white terriers appear predisposed to, and have a high prevalence of, an abnormal mediodistal location of the medial fabella. The authors suggest this is an incidental finding and should not be confused with true pathological fabellar displacement.