Association Between Excessive Joint Laxity and a Wider Hill-Sachs Lesion in Anterior Shoulder Instability

Abstract

Background: Excessive general joint laxity, a negative prognostic factor in joint instability, has not been studied to determine its relationship with bipolar bone loss in anterior shoulder instability.

Purpose/hypothesis: This study aimed to investigate the characteristics of bipolar bone defects in the presence of excessive joint laxity and the clinical outcomes based on the on-track/off-track theory. We hypothesized that (1) patients with excessive joint laxity might have less significant bipolar bone defects compared with those without excessive joint laxity and (2) no significant difference would be found in the clinical outcomes, including recurrence rate.

Study design: Cohort study; Level of evidence, 3.

Methods: This study included 81 patients who had undergone arthroscopic Bankart repair, with (group L; n = 33) or without (group N; n = 48) excessive joint laxity. The presence of excessive joint laxity was defined as a score of ≥4 using Beighton and Horan criteria preoperatively. Bipolar bone lesions were assessed using preoperative 3-dimensional computed tomography. Additional remplissage was performed for cases with off-track or positive engagement test in borderline on-track lesions. The functional outcomes at the 2-year follow-up were assessed using the recurrence rate, Subjective Shoulder Value, Rowe score, University of California Los Angeles shoulder score, active range of motion, and the sports/recreation activity level.

Results: No significant difference was found in the glenoid bone defect between groups (14.1%, group L; 14.4%, group N). Off-track lesions were identified in 39.4% (13/33) of group L and 14.6% (7/48) of group N (P = .011). The mean Hill-Sachs interval to glenoid track ratio was 83.1% in group L and 75.2% in group N (P = .021). Additional remplissage procedures were more frequently performed in group L (48.5%; 16/33) than in group N (16.7%; 8/48) (P = .002). However, no significant difference was observed in the shoulder functional scores and recurrence rates between the groups.

Conclusion: Patients with anterior shoulder instability and excessive joint laxity had significantly wider Hill-Sachs lesions and more off-track lesions than did those with normal joint laxity despite the lack of a significant difference in the glenoid bone defect. However, these differences in the Hill-Sachs lesion were not related to differences in the functional outcomes between the groups.