FATTY MUSCLE DEGENERATION IN CUFF RUPTURES - PREOPERATIVE AND POSTOPERATIVE EVALUATION BY CT SCAN

A preoperative computed tomography (CT) scan grading muscular fatty de generation in five stages was done in 63 patients scheduled for repair of a torn rotator cuff. The results were compared with postoperative evaluation done after a mean of 17.7 months in 57 patients. Postoperat ive arthrographies were also performed in 56 patients. Preoperative CT scans demonstrated that infraspinatus fatty degeneration can occur in the presence of large anterosuperior tears even when the infraspinatu s tendon is not torn; it worsens with time. The subscapularis rarely d egenerates, and when it does it degenerates moderately, even when its tendon is not torn. After an effective surgical repair, moderate supra spinatus degeneration regressed in six of 14 patients; that of the inf raspinatus never regressed but rather, increased, in three patients. O ne of these deteriorations, involving both supra- and infraspinatus, c ould probably be attributed to a partial subscapular nerve injury, Inf raspinatus degeneration was correlated with functional pre- and postop erative impairment of active external rotation. Recurrence of infraspi natus tear was never observed, but recurrence occurred in 25% of supra spinatus repairs. Infraspinatus degeneration had a highly negative inf luence on the outcome of supraspinatus repairs. It seems preferable to operate on wide tears before irreversible muscular damage takes place .