Glenohumeral morphological predictors of recurrent shoulder instability following arthroscopic Bankart repair.

PURPOSE: The purpose of this study was to evaluate glenohumeral morphological features on a magnetic resonance arthrogram (MRA) to determine risk factors for recurrence of anterior shoulder instability following arthroscopic Bankart repair (ABR).

METHODS

A retrospective review of patients who underwent ABR between 2012 and 2017 was performed to identify patients who had recurrence of instability following stabilisation (Group 1). These were pair-matched in a 2:1 ratio for age, gender and sport with a control (Group 2) who underwent ABR without recurrence. Preoperative MRAs were evaluated for risk factors for recurrence, with glenoid bone loss and Hill-Sachs lesions also measured. Multilinear and multilogistic regression models were used to evaluate factors affecting recurrence.

RESULTS

Overall, 72 patients were included in this study, including 48 patients without recurrence and 24 patients with recurrent instability. There was a significant difference between the two groups in mean glenoid bone loss (Group 1: 7.3% vs. Group 2: 5.7%, p < 0.0001) and the rate of off-track Hill-Sachs lesions (Group 1: 20.8% vs. Group 2: 0%, p = 0.0003). Of the variables analysed in logistic regression, increased glenoid anteversion (p = 0.02), acromioclavicular (AC) degeneration (p = 0.03) and increased Hill-Sachs width were associated with increased risk of failure. Increased chondral version (p = 0.01) and humeral head diameter in the anteriorposterior view were found to be protective and associated with a greater likelihood of success.

CONCLUSION

Glenoid anteversion was a risk factor for recurrent instability, whereas increased chondral version and humeral head diameter were associated with higher rates of success following ABR. Glenoid bone loss, presence of an off-track Hill-Sachs lesion, increased Hill-Sachs width and AC degeneration were also associated with failure. These findings should be used by surgeons to stratify risk for recurrence following ABR.

LEVEL OF EVIDENCE: Level III.