Open surgical repair restores joint forces that resist glenohumeral dislocation

Traumatic anterior shoulder instability is a clinical problem often observed in athletes participating in overhead activities. The standard treatment for this condition is surgical repair, which may be accomplished by an open or arthroscopic procedure. The current authors assessed the strength of open repair, by comparing glenohumeral joint forces in intact specimens with specimens with anterior dislocation and open repair. Eighteen shoulders from cadavers were tested on a custom shoulder dislocation device with simulated muscle forces. Bankart lesions were repaired using a three-suture anchor technique combined with capsular advancement. Capsular failures were addressed by sharp dissection of the labrum from bone, then repaired as above, and the experiment was repeated. One-way analysis of variance was used for analyses. All specimens dislocated anteroinferiorly, eight dislocated by bony Bankart failure, and 10 dislocated by capsular failure. Maximum joint compression force for the initial dislocation was 760 +/- 79 N for the specimens with Bankart failures and 690 +/- 59 N for the specimens with capsular failures. The maximum joint compression force for dislocation after repair measured 541 +/- 50 N for the specimens with Bankart failures and 536 +/- 46 N for the specimens with capsular failures. The forces after repair were normalized with respect to the intact shoulders. For specimens with Bankart failures, joint compression and pectoralis major forces were 72% and 62%, respectively, and 79% and 61% for specimens with capsular failures. A three-dimensional digitizing system confirmed restoration of glenohumeral position. These results support clinical data, showing that open Bankart repair adequately restores the static restraints of the glenohumeral joint that resist anteroinferior dislocation.