Computed tomographic features of elbow osteoarthritis predict lameness in small-breed pigs

Objective: To describe CT features of elbow osteoarthritis (OA) in small-breed pigs and determine the ability of CT to predict elbow-related lameness. Methods: Medical records between January 1, 2013, and April 30, 2025 were retrospectively reviewed and included if diagnostic forelimb CT images, reason for CT, signalment, and gait examination were available. Images were scored for OA severity, humeral intracondylar fissure (HIF), subchondral bone cystic lesions, articular margin incongruity, periarticular mineral bodies, and subchondral bone sclerosis (SBS). Exploratory single-predictor logistic regression generalized estimating equation models determined relationships between each finding and odds of lameness. Results: 90 elbows from 49 pigs were included. Computed tomographic findings related to the probability of lameness included OA severity, HIF, articular margin incongruity, periarticular mineral bodies, and SBS. Odds of lameness were 21.97 times as high in pigs with mild elbow OA (95% CI, 1.80 to 268.64) compared to pigs without. Odds of lameness in pigs with HIF (OR, 11.82; 95% CI, 3.17 to 44.04), articular margin incongruity (OR, 5.28; 95% CI, 1.78 to 15.68), periarticular mineral bodies (OR, 3.09; 95% CI, 1.59 to 5.99), and SBS (OR, 4.78; 95% CI, 1.10 to 20.86) were higher when each finding existed on CT. Conclusions: Certain CT findings predict elbow-related lameness, increasing opportunity for early diagnosis and intervention. Clinical Relevance: Lameness is difficult to diagnose in pigs. This study identified new CT findings relating OA to lameness, allowing clinicians to more accurately predict and treat elbow-related lameness in this population.