The muscle strength of recurrent dislocation of the shoulder after Bankart's procedure was evaluated by using a Cybex II, and was compared with that of the non-involved side.
The shoulders of 26 patients on whom we had used Bankart's procedure were analysed. The average follow-up interval was 8.1 months(range 5 to 13 months) post-operatively. Isokinetic muscle strength testing of the shoulder was examined by using a Cybex II at the speed of 30 or 60 degrees/second, for flexion, extension, abduction, adduction, internal rotation, and external rotation. The peak torque was measured as a maximum strength and the percentage of the involved/non-involved side was calculated.
The muscle strength of the involved side was 83.6% in flexion,93.1% in extension,78.8% in abduction,87.1% in adduction,88.6% in internal rotation, and 73.1% in external rotation. The muscle strength of the involved side was lower in all directions than that of the non-involved side, especially in abduction and external rotation.
Then, we examined the correlation between the muscle strength, the number of dislocations, the durations of disease, and the degrees of Bankart's lesion. The muscle strength in abduction and external rotation was significantly lower in the group which consisted of a large number of dislocations, and a long duration of disease. There was no correlation between the muscle strength and the degrees of Bankart's lesion.
The muscle strength plays an important role in the stability of the shoulder after surgery. Therefore, Bankart's procedure is recommended to be performed in the early stages of a recurrent dislocation of the shoulder in order to get good results regarding the postoperative muscle strength and stability.