Progression of Erosive Changes of Glenoid Rim After Arthroscopic Bankart Repair

Abstract

Purpose: To evaluate changes of the glenoid after arthroscopic Bankart repair (ABR) in patients with different preoperative glenoid structures.

Methods: Patients who underwent ABR for traumatic anterior shoulder instability were retrospectively investigated. They were divided into 3 groups on the basis of preoperative glenoid structure by computed tomography (CT): normal glenoid (group N), glenoid erosion (group E), or glenoid defect associated with a bony Bankart lesion (group B). Shoulders in group B were also stratified according to the postoperative status of the bone fragment (union, nonunion, or resorbed). Postoperative changes of glenoid width (Δ) (increase: Δ ≥5%, stable: Δ >-5% to <5%, decrease: Δ ≤-5%) and the extent of glenoid bone loss were investigated by 3-dimensional CT.

Results: A total of 186 shoulders were divided into 3 groups: group N (n = 61), group E (n = 46), and group B (n = 79). At initial postoperative CT, the glenoid width was decreased in 41 shoulders, stable in 20 shoulders, and increased in no shoulders from group N. The respective numbers were 27, 18, and 1 in group E, and 50, 22, and 7 in group B. The glenoid width was reduced in all groups (mean percent change: -8.8%, -5.9%, and -6.1%, respectively). In group B, glenoid width decreased in most of the shoulders without bone union. The glenoid bone loss on the preoperative and postoperative final CT was, respectively, 0% and 8.6% in group N (P < .0001), 9.9% and 12.4% in group E (P = .03), and 10.4% and 7.2% in group B (P = .01). Final glenoid bone loss >13.5% was recognized in 18.2% of group N, 35.7% of group E, and 21.8% of group B.

Conclusions: Glenoid width often decreased after ABR because of anterior glenoid rim erosion, and this change was frequent in patients with preoperative normal glenoid, glenoid erosion, or without postoperative union of a bony Bankart lesion.

Level of evidence: Level 3, Case-control study.