[Impact of fatty degeneration of the suparspinatus and infraspinatus msucles on the prognosis of surgical repair of the rotator cuff].

PURPOSE OF THE STUDY: Rupture of the cuff tendons can induce a fatty degeneration of cuff muscles. In 1989 the authors proposed a grading in 5 stages of this degeneration based on CT scan. The purpose of this study was to determine whether this degeneration had an influence on anatomical and clinical results after surgical repair of the cuff.
MATERIAL AND METHODS: Seventy-four patients operated for a ruptured cuff had prospectively a pre-operative CT scan grading of muscular degeneration, and a post-operative anatomical control by opaque arthrography at about 10.5 months follow-up. Forty-four patients were males and 30 were females. The mean age at operation was 58.7 (40 to 75). Fifty-two ruptures were large involving the supraspinatus and infraspinatus in 17 cases, the supraspinatus and the subscapularis in 20 cases and all three tendons in 15 patients. Twenty-two ruptures were smaller and involved only the supraspinatus. To repair the cuff, it was necessary to advance the supraspinatus muscle in 28 cases and both supra and infraspinatus in 24 cases. No patient was lost for follow-up, and 51 of the 56 having more than one year of follow-up (mean 3 years, maximum 7.5 years) were evaluated according to Constant and Murley score. Two reoperated patients were excluded from the final analysis.
RESULTS: Complete supraspinatus tears after repair recurred in 16 cases (22 p.cent). No infraspinatus rupture occurred after 32 infraspinatus repairs. Re-tears were observed only when a muscular advancement had been performed. Except in one case, re-tears occurred only when supraspinatus and/or infraspinatus were degenerated. The mean Constant score at revision for 49 patients was 66.6 points. According to this scoring system, 67.3 p.cent had a satisfactory result, 24.5 p.cent a fair result, and 8.2 p.cent a bad result. The mean score of the 39 patients having a continent cuff was 67.4 points, and was not significatively better than that of the patients with a re-tear (63.7 points). The best results were noted for the postero-superior tears (74.6 points). The type of repair had no significative influence on the final Constant score. The best improvements in external rotation were observed when a double advancement was performed. The stage of fatty degeneration, particularly of the infraspinatus, had an influence on the final range of motion, particularly in external rotation, and on the final strength. DISCUSSION: The fatty degeneration of supra and infraspinatus is an important prognostic factor of the anatomical and functional results after surgical repair of the cuff. More-over, when it is present, the surgeon may have some difficulties to close the tear during surgery. This study confirms that it is probably better to operate rotator cuff tears before the appearance of irreversible muscular damage, particularly when the lesions extend posteriorly to the supraspinatus.