Presence of Additional Pathology in Low-Grade Acromioclavicular Joint Injuries.

ABSTRACT

OBJECTIVE: To determine if additional pathology is present in low-grade acromioclavicular (AC) joint injuries. DESIGN: Prospective case series. SETTING: Patients were assessed by primary care sports medicine physicians at a single institution between 2019 and 2023. PATIENTS Patients aged 18 to 65 years diagnosed with a type I to III AC injury based on clinical and radiographic evaluation. INTERVENTION Consenting patients underwent magnetic resonance imaging (MRI) evaluation within 21 days of injury. All injuries were treated nonoperatively. MAIN OUTCOME MEASURES: Additional pathologies identified on MRI were reported in a standardized fashion by fellowship-trained musculoskeletal radiologists. RESULTS: Twenty-nine patients (26 men/3 women) were consented with a mean (±SD) age of 28.6 ± 9.5 years. The mean time from injury to MRI was 8.1 ± 5.9 days. Twenty-three injuries were sport related, and 6 were accidental traumas. Based on MRI, injury type was reclassified in 16 of 29 patients, and 13 remained unchanged. Additional pathologies identified included 14 muscle injuries, 5 rotator cuff tears, 5 labral tears, 1 nondisplaced fracture, and 1 intra-articular body. CONCLUSION: MRI evidence suggests that most AC joint injuries are more severe than clinically diagnosed. Identifying additional pathology may alter diagnostic and treatment guidelines for type I to III AC joint injuries.