抄録
Gerber's lift-off test is a valuable method for studying the function of the subscapularis muscle. Isokinetic muscle tests using a torque machine (BIODEX®) reveal the function of inner muscles in the shoulder. The purpose of this study was to determine the clinical significance of Gerber's lift-off test by using isokinetic muscle tests (BIODEX®) after surgery to repair traumatic recurrent dislocation of the shoulder. We examined 25 cases of traumatic recurrent dislocation of the shoulder. All the operations were performed under the modified Putti-Platt method (Nobuhara-Hospital method). The cases were divided into 2 categories according to Gerber's lift-off test: “weak” and “normal”. Statistically the 2 groups were comparable with regard to clinical histories, the Rowe score, and peak torque per body weight. The operations resulted in 25 “weak” cases becoming 7 “weak” and 18 “normal” cases. There were no significant differences between the 2 categories about clinical histories and the Rowe score. The “weak” cases indicated a smaller peak torque per body weight in flexion at 180 degree/sec, extention at 60 degree/sec and 180 degree/sec, in internal rotation at 60 degree/sec (P<0.05), in external rotation at 60 degree/sec and 180 degree/sec, and internal rotation at 180 degree/sec (P<0.01). Dysfuntion of the subscapularis muscle was detected by Gerber's lift-off test but not by the Rowe score because Rowe score's sensitivity was lower. “Weak” cases in Gerber's lift-off test indicated decreased power in almost all the directions. Dysfunction of the subscaplaris muscle could cause decreased musclar strength in the shoulder and in these cases patients should refrain from sporting activities and physical labor. This study concluded that Gerber's lift-off test was a useful test for high sensitivity and a valuable method for evaluating the function of the shoulder after operations.
