The bone block procedure in recurrent posterior shoulder instability.

We analyzed the results of eleven shoulders in ten patients who had a bone block procedure for recurrent posterior shoulder instability after extensive conservative treatment had failed. Five patients had posterior instability with additional laxity in another direction (UPI+), and five patients had unidirectional posterior instability without additional laxity (UPI-). After a median follow-up of 72 (43-102) months there was no recurrent posterior instability in the UPI-group (100% success), but the recurrence rate in the UPI+ group was high (20% success). We concluded from these results that a bone block procedure is not sufficient to treat recurrent posterior shoulder instability in unidirectional posterior instability with additional laxity but it seems to be a good method to treat unidirectional posterior instability without additional laxity.