Eight metacarpophalangeal joints (MCP) of mature horses were evaluated by radiographic and ultrasonographic exams after surgically instability-induced that mimics the early changes of naturally acquired osteoarthritis (OA). Joint circunference, range of motion and lameness score were measured (clinical evaluation). Ten days after surgically joint instability the animals were walked on a horse walker by a 60-day period. Radiography and ultrasonography were taken immediately before desmotomy and 25, 40 and 70 days after surgery. Clinical evaluation was performed at each 7-day intervals. Ultrasonographic changes were observed on day 25 after articular instability while radiographic changes were only visualized on day 40. Joint circunference was significantly higher (P<0.05) in OA joints (25.75cm± 1.1) on day 7 as compared with contralateral joints (24.88cm± 1.0) and a range of motion was significantly less (P<0.05) in OA joints (96.38º± 10.7), on day 25, compared with basal value (109.24º± 10.3) and contralateral joint (108.75º± 8.3). Lameness score significantly increased (P<0.05) over time with mean score 1.5 for the 70-day study period. In conclusion, changes of induced OA joint were earlier and better detected by ultrasonography than by radiography. The measure of joint circunference and range of motion are useful in joint disease evaluation.
equine; joint; osteoarthritis; radiography and ultrasonography
