Diagnostic findings and prognosis following arthroscopic treatment of subtle osteochondral lesions in the shoulder joint of horses: 15 cases (1996-1999)

Objective-To determine clinical, scintigraphic, radiographic, and arthrosco pic findings and results of treatment in horses with lameness attributable to subtle osteochondral lesions of the shoulder joint. Design-Retrospective study. Animals-15 horses. Procedure-Medical records were reviewed, and results of physical examinatio n, scintigraphy, radiography, arthroscopy, and treatment were recorded. Results-Severity of lameness ranged from grade 1 to 4. Response to shoulder flexion or extension was variable. Twelve horses had a narrow upright foot . Intra-articular anesthesia of the shoulder joint localized the cause of t he lameness to the shoulder joint in 9 of 10 horses. Scintigraphic abnormal ities were detected in 4 of 6 horses. Radiographic lesions were subtle and included glenoid sclerosis, focal glenoid lysis, small glenoid cysts, and a lterations in the humeral head contour. Arthroscopic evaluation confirmed c lefts in the glenoid cartilage, glenoid cysts, a humeral head cyst, fibrill ation of the humeral head cartilage, cartilage fragmentation, or a nondispl aced fracture of the humeral head. After treatment, 12 horses returned to t heir previous level of performance, 1 was sound for light riding. 1 remaine d lame, and 1 was euthanatized because of chronic lameness. Conclusions and Clinical Relevance-Results suggest that a combination of ph ysical examination, scintigraphy, and radiography is necessary to diagnose subtle osteochondral lesions of the shoulder joint in horses. Arthroscopy c an be used to confirm the diagnosis and treat cartilage and subchondral bon e lesions. Young and middle-aged horses with subtle osteochondral lesions o f the shoulder joints have a good prognosis for return to performance follo wing arthroscopic treatment.