[Histological lesions of supraspinatus tendons in full thickness tears of the rotator cuff].

PURPOSE OF THE STUDY: Iterative tears after simple tendon bone suture of transfixiant ruptures of the rotator cuff are frequent. The frequency of iterative ruptures had seemed to be correlated to the importance of the preoperative fatty degenerations of the cuff muscles. But fatty degeneration cannot account for iterative ruptures occurring with no or little preoperative muscle fatty degeneration. The authors have tried to know if iterative ruptures could also be accounted for by the presence on repaired tendinous stumps of histological lesions which are known to lower their mechanical quality, and if such was the case, they have tried to know what could be the impact of these lesions on the repairing technique by suturing cuff ruptures. MATERIAL AND
METHOD: Thirty-two distal stumps of ruptured supraspinatus, resected on more than 1 cm to eliminate macroscopic tendinous lesions (thin, lacerated, cleaved, hardened or whitish tendons) and to reach a new stump, slightly bleeding and thick enough to hold the stitches correctly, have been studied on longitudinal histological slides.
RESULTS: All the tendinous resected stumps had histological anomalies: dilacerations lesions of the conjunctive tissue, fatty infiltrations, necrosis, scar lesions and micro calcifications were found. The histological lesions were often associated. The histological lesions were an average 4 mm shorter than those of the tendinous resection. In 18 cases however the whole of the resected tendon was histologically abnormal. DISCUSSION: Tendinous histological lesions found on the whole or almost the whole length of the macroscopically abnormal tendinous stumps diminish the mechanical quality of the tendons. Insufficient resection of the tendinous stumps leaving macroscopical lesions and therefore histological lesions could account for iterative ruptures in the first post operative year. Yet complete resection of the macroscopically abnormal tendinous stump does not entail that the neo tendinous stump to be repaired is histologically normal. This encourages to put the stitches well within the zone of the tendinous resection and to bury the tendinous stumps into a highly vascular bony trough. But tendinous resection although logical from the histological and mechanical point of view widens the rupture of the cuff to be repaired. It can make sutures under tension, which can entail iterative ruptures. Musculo-tendinoplasty appears then necessary to perform sutures without tension.
CONCLUSION: Histological lesions of tendinous stumps of cuff ruptures correspond roughly to tendinous macroscopic lesions. They could be at the origin of iterative ruptures that take place after simple tendon-bone sutures of ruptured cuffs which are not accounted for by muscular fatty degeneration. They could also partly account for iterative ruptures taking place when pre operative fatty degeneration is evident. It seems logical to resect macroscopically abnormal tendinous stumps before performing a suture. But the tendon-bone suture without tension is then often possible only with musculo-tendinoplasties.