Is preoperative glenoid defect size a reliable indicator of postoperative recurrence after arthroscopic Bankart repair in teenage competitive athletes?

BACKGROUND: Being younger than 20 years of age at the time of arthroscopic Bankart repair (ABR) is known to be one of the most important risk factors for postoperative recurrence of instability. When deciding on the appropriate surgical approach, surgeons generally consider only the size of a critical glenoid defect, and most of them do not take into account factors such as the size of bone fragments and possible bone union after arthroscopic bony Bankart repair (ABBR). Therefore, this retrospective study aimed to clarify the risk factors for postoperative recurrence after ABR in teenage competitive athletes by focusing on glenoid rim morphologies and bone union. METHODS: Participants were 115 teenage competitive athletes without a capsular injury who underwent primary ABR for chronic traumatic anterior instability and were followed up for a minimum of 2 years. Possible risk factors for postoperative recurrence were investigated by univariate and multivariate analysis. In shoulders with a glenoid defect and bone fragment, the influence of glenoid defect size and bone fragment size on bone union after ABBR was also investigated. RESULTS: Postoperative recurrence was seen in 16 patients (13.9%). Regarding glenoid defect size, recurrence was seen in 1 (3.2%) of 31 shoulders with a glenoid defect smaller than 5% (including those with a normal glenoid), 15 (22.1%) of 68 shoulders with a glenoid defect of 5%-20%, and 0 (0%) of 16 shoulders with a glenoid defect of 20% or larger (P = .009). Regarding bone union, recurrence was seen in 4 (6.9%) of 58 shoulders with complete or partial bone union after ABBR and 8 (40%) of 20 shoulders with nonunion or disappearance of the bone fragment (P = .001). Regarding bone fragment size, recurrence was seen in 12 (20.7%) of 58 shoulders with a small or no bone fragment (<7.5%) and in 3 (8.6%) of 35 shoulders with a large bone fragment (≥7.5%; P = .154). Multivariate analysis identified non-union or disappearance of the bone fragment after ABBR as a significant risk factor for recurrence. Complete or partial bone union was seen in 25 (58.1%) of 43 shoulders with a small bone fragment (<7.5%) and 33 (94.3%) of 35 shoulders with a large bone fragment (≥7.5%; P < .001). CONCLUSIONS: In teenage competitive athletes, bone union after ABBR affects postoperative recurrence after ABR, regardless of the preoperative glenoid defect size, and bone union rate after ABBR is significantly influenced by bone fragment size.

Unrecognized glenoid fracture in opposite shoulders with symptomatic anterior instability.

BACKGROUND: The purpose of the present study was to investigate the characteristics of unrecognized glenoid fracture in opposite shoulders with symptomatic anterior instability. METHODS: Participants were 38 patients, who had complaints of instability on only one side (symptomatic shoulder) and had no complaints despite of a glenoid fracture on the other shoulder (asymptomatic shoulder) from 2011 to 2020. Factors that could influence the onset of symptoms including glenoid rim morphology were retrospectively investigated. RESULTS: Among the asymptomatic shoulders, 16 had a single traumatic event and 22 had no history of trauma. The glenoid morphology was normal in 6, erosion in 12 and bony Bankart in 20 on the symptomatic side, whereas the respective shoulders were 0, 16 and 22 on the asymptomatic side. Bone union of bony Bankart was complete in 9, partial in 3 and non-union in 8 on the symptomatic side, whereas the respective shoulders were 18, 3 and 1 on the asymptomatic side. The mean glenoid defect size was 10.4% and 7.8%, and the mean bone fragment size was 5.0% and 4.5%, respectively. The mean medial displacement of bone fragments was 2.6 mm and 1.0 mm, respectively (p < 0.001). A larger glenoid defect (≥10%) was recognized in 19 symptomatic shoulders and 10 asymptomatic shoulders. Among them, erosion was solely recognized in 5 symptomatic shoulders. In shoulders with bony Bankart, all 10 asymptomatic shoulders had a completely or partially united fragment with less than 2 mm displacement. On the other hand, among 14 symptomatic shoulders, united fragment was solely recognized in 8 shoulders, in which medial displacement was less than 2 mm in 3 shoulders. CONCLUSIONS: Even if a glenoid fracture occurred, symptom such as instability or pain was not always recognized by all patients. Regardless of glenoid defect size, shoulders with a completely or partially united bone fragment and with less than 2 mm displacement were found to be asymptomatic.