Paper 91: Anteroinferior Glenoid Rim Fractures in Shoulder Instability Patients Over 50: A Matched Cohort Analysis of Risk Factors, Treatment Strategies, and Outcomes

Abstract

Objectives: Background:Although they are common, there remains a paucity of data regarding traumatic anterior shoulder dislocations (ASI) associated with anteroinferior glenoid rim fractures (AGRF) in older patients.Purpose:To describe the incidence of AGRF in this population following ASI, identify risk factors for AGRF, compare treatment strategies, and compare clinical outcomes of patients with and without an associated AGRF.Methods:An established geographic medical record system was used to identify patients >50 years of age with ASI between 1994 and 2016. Patients with radiographic evidence of AGRF were identified and matched 1:1 to patients without AGRF. Comparative analysis was conducted to determine differences between groups.Results:Overall, 186 patients were identified with a mean follow-up of 10.4 years (range, 2.0 – 25.4). Of these, 42 (22.6%) had AGRF and were matched to 42 control patients without AGRF. Average age was 58.9 and 58.2 years for the AGRF and control groups, respectively. Rates of surgical intervention (29% vs. 43%), recurrent instability (14% vs. 17%), progression of osteoarthritis (34% vs. 39%), and conversion to arthroplasty (2% vs. 5%) were similar between AGRF and control cohorts. Control patients were more likely to report recurrent pain (p=.046). For patients with AGRF, increased bone fragment size (OR 1.1) and increased BMI (OR 1.2) correlated with an increased risk for surgery. The cut-off value for surgery in patients with AGRF was a fragment size ≥33% of the glenoid width.Conclusions:In patients ≥ 50 years at presentation of ASI, 22.6% presented with an associated AGRF. Increased fragment size and greater patient BMI were significant factors associated with undergoing surgical intervention; however, most patients did not require surgery. Patients without AGRF were more likely to report recurrent pain, possibly due to a higher prevalence of rotator cuff derangement. Overall, the presence of an AGRF did not portend a worse prognosis as treatment strategies and long-term outcomes in terms of recurrent instability, progression of osteoarthritis, and conversion to arthroplasty were similar between patients with and without AGRF at the time of ASI diagnosis.