Abstract
BACKGROUND: The diagnostic accuracy of magnetic resonance imaging (MRI) and magnetic resonance arthrography (MRA) for detecting labral tears is well established in femoroacetabular impingement but remains unclear in dysplastic hips undergoing hip arthroscopy (HA) combined with periacetabular osteotomy (PAO). PURPOSE: To determine the sensitivity and specificity of MRI and MRA in identifying labral tears in patients with dysplasia undergoing HA combined with PAO. STUDY DESIGN: Cohort study (diagnosis); Level of evidence, 3. METHODS: A retrospective, real-world study was conducted at a single tertiary hip preservation center. Patients included in the analysis had undergone primary HA and PAO with available radiologist interpretation for labral assessment. Diagnostic accuracy of MRI and MRA for detecting labral tears was assessed using arthroscopic findings as the reference standard. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), positive likelihood ratio (LR+), and negative likelihood ratio (LR-) were calculated. RESULTS: A total of 122 patients (mean age, 22.3 years; SD, 5.6; 90% women) were included. Radiographic measurements showed a mean lateral center-edge angle of 22.91° (SD, 6.52), an acetabular index of 8.87° (SD, 5.27), and a Tönnis grade of 0.09 (SD, 0.35). Both MRI and MRA demonstrated low sensitivity (55% and 54.1%, respectively) and low specificity (38.5% and 45.5%, respectively). The PPV was moderate (67.3% for MRI; 71.4% for MRA), and the NPV was low (27% for MRI; 31.3% for MRA). LR+ and LR- values of MRI and MRA were close to 1. CONCLUSION: This study highlights the limited diagnostic accuracy of MRI and MRA for identifying labral tears in patients with hip dysplasia undergoing combined HA and PAO. Operative decisions regarding labral treatment at the time of PAO should not be based solely on preoperative imaging.