1999 年 23 巻 2 号 p. 357-360
The purpose of this study was to evaluate anterior translation of the glenohumeral joint (GHJ) for patients with traumatic anterior instability of the shoulder by examination under anesthesia. We retrospectively studied the bilateral shoulders of 170 patients, who were diagnosed and operated on as unilateral traumatic anterior instability of the GHJ. Before each operation, we graded the amount of anterior translation of the humeral head relative to the center of the glenoid fossa at 90 degrees of abduction and neutral rotation under general anesthesia, utilizing a modified 5-step grading method reported by Hawkins et al. Intraarticular lesions were classified into 5 types: labral detachment type, labral defect type, small bony fragment type, big bony fragment type, and bony defect type. The grades of the anterior translation in each type were statistically compared, using a Mann-Whitney U test. The statistical significance was set at 0.05. The anterior translation of the involved GHJ for a small bony fragment type was significantly smaller than those for other types. The anterior translation of the uninvolved GHJ for a small bony fragment type was significantly smaller than those for the labral detachment type and the big bony fragment type. The anterior translations of the involved GHJ significantly increased more than the uninvolved GHJ in all types.