Anterior glenoid rim resorption after arthroscopic Bankart repair by the footprint fixation technique and its correlation with the healing of the repaired capsulolabral complex: a computed tomography and magnetic resonance arthrography imaging study

Background

Studies have revealed that anterior glenoid rim bone resorption occurs in the early stage after arthroscopic Bankart repair (ABR) if bony Bankart lesions are absent or fail to heal. However, this structural change has never been studied after repair by footprint fixation (FF). Additionally, the relationship between the extent of rim resorption and healing of the repaired capsulolabral complex (CLC) remains unclear. Therefore, this study aimed to investigate anterior glenoid rim changes after ABR by FF and to elucidate the correlation between rim resorption and the healing of the repaired CLC.

Methods

This was a retrospective study on shoulders that underwent ABR by a combination of knotless twin anchor FF and single row techniques for anterior shoulder instability from January 2022 to June 2023. From 44 shoulders, we included 23 after excluding 14 with preoperative bony Bankart lesions and 7 with missing postoperative imaging. We used 3-dimensional computed tomography scans to calculate the change in glenoid width (Δ%) due to anterior glenoid rim change from baseline to 3 months postoperatively and images from magnetic resonance arthrography, which was performed at around 5 months postoperatively, to evaluate CLC healing according to a 3-point grading scale (good, 3 points; fair, 2 points; poor, 1 point) on 6 oblique axial slices perpendicular to the glenoid long axis. Finally, we calculated the correlation coefficient between Δ% and the healing index, that is, the mean CLC healing grade of the 6 slices.

Results

Glenoid width decreased by 7.2% (range, 2.0%-12.8%; P < .001). The mean CLC healing index was 2.59 points (range, 1.8-3.0). The Δ% showed a moderate positive correlation with the healing index (correlation coefficient, 0.55; P = .006).

Conclusion

Anterior glenoid rim resorption also occurs after ABR by the combination of FF and single row technique at 3 months postoperatively. Although this is a preliminary result, the extent of rim resorption is greater with better healing of the repaired CLC.