Contracted joint capsule affects labral and chondral lesions in patients with frozen shoulder

Purpose: Intra-articular pathologies, such as labral and chondral lesions, are common in patients with frozen shoulder. This study evaluated the correlations between the range of motion and labral and chondral lesions in patients with frozen shoulder and investigated their pathophysiologies. Methods: In total, 125 individuals (53 men and 72 women) who underwent arthroscopic pan-capsular release between 2014 and 2020 were included in the study. The range of motion was measured using scapular fixation and true glenohumeral motion under general anaesthesia. The American Shoulder and Elbow Surgeons Shoulder score and the Shoulder Rating Scale score of the University of California, Los Angeles were used to compare intra-articular pathologies. Results: More than 80% of patients with frozen shoulder had labral pathologies, and nearly half of them had chondral pathologies. Labral lesions extending to the anterior rim of the glenoid had a greater range of motion and the greatest total American Shoulder and Elbow Surgeons Shoulder score. More severe chondral lesions had a lesser range of motion, but presented the greatest function scores and the lowest strength scores according to the Shoulder Rating Scale of the University of California, Los Angeles. The pain scores of the American Shoulder and Elbow Surgeons Shoulder score and the Shoulder Rating Scale of the University of California, Los Angeles were not correlated with the degree of these pathologies. The traction force affected the labrum during true range of motion, and the compression force occurred on the articular cartilage during internal rotation at 90° of forward flexion during diagnostic arthroscopy. Conclusion: Labral and chondral lesions are common in patients with frozen shoulder. Adherence to the capsulolabral complex induced a limited range of motion and labral and chondral pathologies. Diagnostic arthroscopy with motion is an important method of reproducing the pathogenesis of intra-articular structures for patients with frozen shoulder. Level of evidence: Level III.