Superior labrum almost always tears following subscapularis injuries

Purpose and Hypothesis: The subscapularis tendon is the major medial support of the long head of biceps tendon (LHBT). Thus, tears of subscapularis may cause biceps tendon subluxation or dislocation. A subluxated biceps tendon may cause a superior labrum injury because of the changed direction of the biceps tendon pulling vector. The purpose of this study is to express the frequency of superior labrum anterior posterior (SLAP) lesions accompanying subscapularis tears. Methods: The digital files of 2010 patients who underwent shoulder arthroscopy were reviewed retrospectively. 141 videos of 141 patients with subscapularis tear were examined in terms of superior labrum and biceps tendon injuries by one of the authors in this study. The results were compared with those of all the 2010 patients who underwent shoulder arthroscopy for any reason. The statistical analysis was made with a statistics programme by the Independent Samples T-Test. Results: There were 113 videos on which the superior labrum and LHBT could be examined precisely. Mean age was 57.8 and 66% of the patients were female. 96.4% of the 113 patients were having a SLAP lesion. 10.6% of those were SLAP I and 89.4% were SLAP II lesion. Out of 2010 patients, the SLAP lesion ratio was 32.2% of which 4.9% were SLAP I. That difference between the patients with and without subscapularis tear was statistically significant. Conclusions: Following the loss of medial support, the LHBT and its pulling vector subluxate anteriorly resulting in a tear of the superior labrum from anterior to posterior. In this study, SLAP lesions were strongly correlated with subscapularis tears as well. Furthermore, the synovial hypertrophy initiated after a superior labrum pathology at superior aspect of the glenoid spreads over the LHBT. An inflamed LHBT firstly degenerates, and then ruptures. According to this study, tears of subscapularis should be repaired when encountered in order to prevent the upcoming secondary intra-articular disorders. [Figure: see text]