Introduction and Objectives: According to the literature, the prevalence of osteoarthritis in shoulder instability is about 4 to 31%. In these studies we used imaging techniques with little sensitivity to early alterations of cartilage. The aim of this study is to arthroscopically assess the prevalence and distribution of osteoarthritis in shoulder instability and analyze associated risk factors.

Materials and Methods: In a group of 64 patients (mean 28.9 years of age, range 15–55) we arthroscopically assessed the degree and distribution of glenohumeral arthritis at the time of surgical stabilization classifying them into 3 groups according to severity. We determined the correlation of the degree of osteoarthritis (Pearson coefficient) with sex, dominance, age, age at the first episode, preoperative sports activities, degree of instability, laxness and number of dislocations and subluxations.

Results: 63 patients (98.5%) had chondral or synovial lesions of a degree of severity categorized as slight, moderate or severe in 26 (40.6%), 35 (54.7%) and 3 (4.7%) patients respectively. The most frequent findings were Hill-Sachs type lesions and anteroinferior glenoid fibrillation. We found a significant correlation between degree of severity of the arthritis (p< 0.05) and the age of the patient, age at the first dislocation and number of dislocations.

Discussion and Conclusions: The prevalence of osteoarthritis in shoulder instability is greater than has been described. The fact that there is a positive correlation between the number of dislocations suffered and the severity of the arthritis could be a reason for carrying out early stabilization in these patients.