부산대학교 도서관

[Purpose] We measured the muscle strength of the shoulder in patients after a modified Bristow operation and compared it with the strength of the intact side.[Subjects] The subjects were 14 right-handed men who underwent a modified Bristow operation and could be directly examined. The patients were 16 - 30 years old (mean 20.1) at the time of surgery.[Methods] Internal and external rotator strength was measured in the standing position using a Cybex 340 to examine the following: 1) The angle of occurrence of the peak torque,2) the peak torque,3) maximum work, and 4) the ratios of the injured shoulder values to those of the intact shoulder. Twenty right-handed men,17-34 years old (mean 23.8), without shoulder disorders were used as the controls, and each measurement was performed 5 times.[Results] The results of the Smirnoff-Grubbs rejection test confirmed that the measurements were reproducible. A peak internal rotation torque was observed slightly externally, and that of an external rotation was observed slightly internally. The peak torque of internal rotation was reduced 4 months postoperatively, and had not recovered to its preoperative value even 6 months postoperatively, however; it was greater than the preoperative value one year postoperatively. Since the subjects returned to their athletic activities 6 months postoperatively, the muscle strength was assumed to have been greater than its preoperative value at this point in time, however, this suggests that it is difficult to evaluate the time to return on the basis of muscle strength alone.The peak external rotation torque was only slightly reduced 4 months postoperatively, and was still slightly greater than the preoperative value 6 months postoperatively. It became approximately the same as the the preoperative value one year postoperatively. There seemed to be only a slight postoperative influence on external rotator strength because of the absence of surgical stress on the muscle strength of an external rotation. [Conclusions] Measurements were performed on 20 healthy subjects, and their reproducibility was confirmed. The peak torque of internal rotation was observed slightly externally, while that of external rotation was observed slightly internally. The internal rotator strength was greater than the preoperative value and the value of the intact shoulder one year postoperatively. The muscle strength of external rotation was only slightly reduced after surgery.