The treatment of posterior shoulder instability remains a clinical problem because it is uncommon and its criteria is not clear. In this paper, we reported the results of a posterior glenoid osteotomy (Scott) for posterior instability of the shoulder. From 1978 to 1997, we operated on 17 patients with posterior shoulder instability in our hospital. There were 11 males and 6 females with a mean age of 16.7years old (range; 10 to 29 years old). The average follow-up period was 7 years 5 months (range; 10months to 18 years 8 months).
A posterior subluxation of the shoulder could be felt when an examiner pushed humeral head posteriorly in all the patients. The posterior subluxations were demonstrated in axillary stress roentgenograms. Seven cases showed a habitual subluxation and three cases could subluxate their shoulder at will. Six cases could demonstrate habitual and voluntary subluxation.
In the first 4 cases, we performed Scott's original method and tightening of the posterior capsule. The remaining 13 patients were operated on by a modified Scott's procedure ( a skin incision was changed and a bone graft was harvested from the iliac bone) and tightening of posterior capsule. All the patients were evaluated by the shoulder evaluation score of the Japanese Orthopaedic Association.
The pre-operative average point of the JOA score was 74.7 points, which improved to 95.3 points at the final follow-up. Recurrence was observed in 3 cases, which had voluntary posterior subluxation and inferior instability. All these patients were female. One of them also had a general joint laxity. All except these three patients showed no difficulties in ADL and sports activities. From this study it can be suggested that satisfactory results can be obtained in the patients with posterior shoulder instability by posterior glenoid osteotomy.
