Department of Orthopaedic Surgery. Fundación Jiménez Díaz. Madrid, Spain

Purpose: The reported prevalence of osteoarthritis associated to shoulder instability (dislocation arthropathy) ranges from 4 to 31.2%. However, the studies on this topic have been performed using imaging techniques lacking of enough sensitivity to detect early cartilage abnormalities. The purpose of this study is to evaluate arthroscopically the prevalence of osteoarthritis to characterize chondral damage in shoulder instability, and to determine which factors could be responsible for these abnormalities

Methods: Sixty-four patients (mean age 28.9, range 15 to 55, years) were evaluated arthroscopically for osteoarthritis at surgery following the score of Calvo et al. The prevalence, topographic distribution and severity of synovial and chondral lesions was recorded and graded into three stages. Osteoarthritis was correlated (Pearson´s coefficient) with those factors that might potentially determine their prevalence and severity: gender, handedness, patients age, age at first dislocation, preoperative sporting activity, level of instability, number of dislocations and subluxations, and ligament laxity.

Results: Sixty-three patients (98.5%) showed synovial or chondral lesions, that were graded as mild, moderate and severe in 26 (40.6%), 35 (54.7%), and 3 (4.7%) patients, respectively. Hill-Sachs lesion of the humeral head and fibrillation on the anterior inferior glenoid cartilage were the most common findings. The age of the patient, the age at first dislocation, and the number of dislocations correlated significantly with the severity of osteoarthritis (p<0.05).

Discusión: Osteoarthritis associated to instability is more prevalent than previously reported. The fact that the number of dislocations showed a positive correlation with the severity of instability could be an argument for early shoulder stabilization.