The purpose of this study was to evaluate clinical outcomes of arthroscopic repairs of rotator cuff tears involving the subscapularis (SSC) tendon. Between January 2006 and September 2008 we treated 139 cases of rotator cuff tears (RCTs). Among them, 49 cases (35%) showed partial or complete subscapularis tendon tears. The arthroscopic rotator cuff repairs were performed in 13 of 49 cases. In the 13 cases, the average age at operation was 68.3 years old. The mean pre-operation period was 14.4 months. The tear size was classified by the longitudinal distance and the tendon retraction during arthroscopic surgery. In the longitudinal distance, the superior one-third of the footprint was torn in 7 cases, the superior two-thirds of the footprint in 6 cases. In the tendon retraction, there were 9 cases between lateral articular margin and the glenoid surface, 4 over the glenoid surface. We arthroscopically repaired RCTs by using the double-row technique. The clinical preoperative and postoperative assessment was performed using the JOA score, range of motion, the lift off test, and the belly press test. Their results improved significantly. The MRI assessment at 6 months after the surgery was performed on repair integrity according to Sugaya's classification. Type I and II was detected in 7 cases, type III in 4. Postoperative MRI findings showed no re-tear of SSC. The MRI assessment compared the repair integrity and the preoperative tear size, the fatty infiltration. The type III by Sugaya's classification was detected in 3 cases when the tear size was larger and the fatty infiltration stage by Goutallier's classification was stage III. In conclusion, the clinical and structural outcomes of arthroscopic repairs of rotator cuff tears involving the SSC were satisfactory. The preoperative tear size and fatty infiltration of the SSC tears might affect the postoperative repair integrity.
