Risk factors for recurrence of shoulder instability after arthroscopic bankart repair

Background: The higher failure rates reported with arthroscopic stabilization of traumatic, recurrent anterior shoulder instability compared with open stabilization remain a concern. The purpose of this study was to evaluate the outcomes of arthroscopic Bankart repairs with the use of suture anchors and to identify risk factors related to postoperative recurrence of shoulder instability. Methods: Ninety-one consecutive patients underwent arthroscopic stabilization for recurrent anterior traumatic shoulder instability. The mean age (and standard deviation) at the time of surgery was 26.4 +/- 5.4 years. Seventy-one patients were male. Seventy-nine patients were involved in sports (forty, in high-risk sports). Capsulolabral reattachment and capsule retensioning was performed with use of absorbable suture anchors (mean, 4.3 anchors; range, two to seven anchors). All patients were prospectively followed, and, at the time of the last review, the patients were examined and assessed functionally by independent observers. Results: At a mean follow-up of thirty-six months, fourteen patients (15.3%) experienced recurrent instability: six sustained a frank dislocation and eight reported a subluxation. The mean delay to recurrence was 17.6 months. The risk of postoperative recurrence was significantly related to the presence of a bone defect, either on the glenoid side (a glenoid compression-fracture; p = 0.01) or on the humeral side (a large Hill-Sachs lesion; p = 0.05). By contrast, a glenoid separation-fracture was not associated with postoperative recurrent dislocation or subluxation. Recurrence of instability was significantly higher in patients with inferior shoulder hyperlaxity (p = 0.03) and/or anterior shoulder hyperlaxity (p = 0.01). On multivariate analysis, the presence of glenoid bone loss and inferior hyperlaxity led to a 75% recurrence rate (p < 0.001). Lastly, the number of suture-anchors was critical: patients who had three anchors or fewer were at higher risk for recurrent instability (p = 0.03). Conclusions: In the treatment of traumatic recurrent anterior shoulder instability, patients with bone loss or with shoulder hyperlaxity are at risk for recurrent instability after arthroscopic Bankart repair. At least four anchor points should be used to obtain secure shoulder stabilization.