Use of Preoperative Magnetic Resonance Imaging to Predict Clinical Outcomes After Core Muscle Injury Repair

BACKGROUND: Core muscle injury (CMI), often referred to as a sports hernia or athletic pubalgia, is a common cause of groin pain in athletes. Imaging modalities used to assist in the diagnosis of CMI include ultrasound (US) and magnetic resonance imaging (MRI). PURPOSE: To determine if preoperative MRI findings predict clinical outcomes after surgery for CMI. STUDY DESIGN: Cohort study; Level of evidence, 3. METHODS: A retrospective cohort study was performed on a consecutive series of patients who were operatively treated for CMI by a single surgeon. CMI was diagnosed based on history, physical examination, and a positive US. In addition, all patients underwent a preoperative MRI. Patients were divided into 2 groups based on whether the MRI was interpreted as positive or negative for CMI. All patients underwent mini-open CMI repair. Patient-reported outcomes (PROs) were collected both pre- and postoperatively and included a visual analog scale (VAS) for pain, the University of California, Los Angeles (UCLA) activity score, and the modified Harris Hip Score. RESULTS: A total of 39 hips were included in this study, of which 17 had a positive MRI interpretation for CMI (44%) and 22 had a negative MRI interpretation (56%). Mean age at the time of surgery was 35 years (range, 17-56 years), and mean follow-up was 21 months (range, 12-35 months). No significant difference was found between groups in mean age or time to follow-up. Patients in both groups demonstrated significant improvement from preoperative to most recent follow-up in terms of the UCLA activity score (P < .05). VAS scores significantly improved for patients with a positive MRI interpretation (P = .001) but not for those with a negative MRI interpretation (P = .094). No significant difference on any PROs was found between groups at the most recent follow-up. CONCLUSION: Successful clinical outcomes can be expected in patients undergoing surgery for CMI diagnosed based on history, physical examination, and US. Patients with a preoperative MRI consistent with CMI may experience greater improvement in pain postoperatively, although MRI does not predict postoperative activity level in these patients.