Poster 119: MRI evidence of labral tears in healthy young athletes without hip pain

OBJECTIVES: The prevalence of labral tears in asymptomatic active adults has been reported, but the prevalence of labral tears and other incidental hip lesions in the asymptomatic adolescent population has not yet been determined. The purpose of this study was to determine the prevalence of hip abnormalities detected on 3T MRI in an active adolescent population with no hip symptoms and, secondarily to compare with hip abnormalities found in adolescents who underwent an MRI for a hip related condition. METHODS: Following IRB approval, adolescent patients presenting with isolated knee pain requiring knee MRI were prospectively recruited to have a 3T MRI of their asymptomatic contralateral hip (ASx). A comparison group of adolescent subjects who underwent an MRI for hip pain was enrolled retrospectively (Sx). All MRI scans were anonymized and randomized. Based on preliminary power analysis, 50 subjects were enrolled for each cohort. Blinded to the patient’s cohort status, clinical and demographic data, 2 fellowship-trained musculoskeletal radiologists evaluated these MRI’s independently for abnormal hip lesions, including labral tears. Inter-reader reliability was evaluated using Cohen’s Kappa. A chi-square or Fisher’s exact test was used to compare the prevalence of these hip lesions between the two cohorts. RESULTS: Average patient age was 14.9 years for both cohorts (range 9-18 years); 52% were female. In the ASx group, incidental labral tears were found in 18%, labral/paralabral cysts 6%, cartilage lesion 0%, subchondral cyst 0%, ligamentum teres tear 0%, femoral fibrocystic change 0%, cam lesion 30%, acetabular bone edema 0%, acetabular rim fracture 0%. The prevalence of labral tears (30%, P-value 0.160) and cam lesion (36%, P-value 0.523) in the Sx group was not significantly different from that of the ASx cohort. CONCLUSIONS: Labral tears were present on 3T MRI’s of adolescents with and without hip pain. While MRI is essential to confirm the surgeon’s suspicion and to detect unexpected pathology, clinical exam and history are crucial in pinpointing clinically relevant abnormal imaging findings.