[Early failure of anterior bone block in multidirectional shoulder instability: a case report]

We report the case of a 47-year-old female patient who developed predominantly anterior multidirectional glenohumeral instability. After rehabilitation, this patient was treated surgically with an anterior coracoid bone block using the Latarjet technique. The second postoperative day, the control scan revealed posterior glenohumeral dislocation. The patient underwent a second operation for a posterior iliac block. At last clinical follow-up (six years), the patient had normal shoulder motion; shoulder function was considered excellent using the clinical scores. We recall the pathogenic hypotheses explaining multidirectional shoulder instability and discuss the proposed treatments. This case illustrates the difficult diagnosis and therapeutic management of multidirectional instability. Under general anesthesia, examination showed that posterior laxity predominated while paradoxically, the patient presented predominantly anteromedial dislocations. This case is also exceptional by the development of posterior dislocation, an unusual postoperative complication after an anterior bone block; we describe the therapeutic options. In the event of multidirectional instability with bone injuries, we recommend a block in the direction of the instability. Preoperative examination under general anesthesia can be helpful in understanding the mechanism of residual postoperative instability, which would require complementary surgical stabilization.