Clinical Features of a Rupture of the Subscapularis Tendon

Abstract

The purpose of this study was to compare the clinical features of the subscapularis tendon avulsed from the lesser tuberosity with those of the subscapularis tendon torn from the rotator interval to the bicipital groove.
Sixty-two shoulders in 62 patients were diagnosed with isolated rupture of the subscapularis tendon (SSC) or rupture of the SSC with the anterior part of the suprasupinatus tendon at Nobuhara Hospital. We divided the pattern of the rupture of the SSC into two groups. Group A (N=26): the SSC avulsed from the lesser tuberosity. Group B (N=36): the SSC was torn from the rotator interval to the bicipital groove. The causes of the injuries, the arthrographical findings and the relationships between ruptures of the SSC and the long head of the biceps tendon (LHB) were examined in both groups. The clinical results were evaluated in 22 patients, who were assessed directly at a mean follow-up time of 83 months.
In group A, trauma caused the injuries in 92% shoulders. In group B, trauma caused them in 89%shoulders. An arthrography detected the SSC ruptures in group A (88%) more frequently than in group B (38%). Eight of 9 shoulders with a subluxation or dislocation of the LHB belonged to group A (p>0.01). The clinical results by 6 months had improved except for the external internal rotations in range of motion, and they were maintained until the final follow-up. The results of this study indicate that the SSC avulsed from the lesser tuberosity had a more frequent subluxation or dislocation of the LHB than SSC from the rotator interval to the bicipital groove.