Purpose or Case Report: Hip pain in the active adolescent can be a diagnostic challenge. Labral tears are a common cause of pain, but on average, a lag time of greater than 2 years exists before a diagnosis is achieved. Leading etiologies of labral pathology include: trauma, femoroacetabular impingement, and dysplasia. A better understanding of hip pathology, in this age group and the development of less-invasive hip arthroscopy and surgical repair, has led to an increased number of pediatric MR hip arthrograms (MRA) being performed.

The purpose of this investigation was to evaluate the accuracy of our MRA reports with arthroscopic findings and create a pictorial radiologic-arthroscopic correlation. This study will assist both radiologists whom may be formally trained in pediatric radiology but have variable experience and/or training in musculoskeletal radiology, as well as our clinical colleagues to better understand the diagnostic utility of MRA.
Methods & Materials: A retrospective review of the MRA reports was performed at our institution between January 1, 2015 and October 1, 2017. The EMR was utilized to ascertain clinical management. The diagnostic efficacy of the MRA radiology reports is determined based on the arthroscopic report findings; the absence or presence of labral pathology is identified. A third category separating labral pathology into either definite labral tear verses labral fraying/irregularity is also evaluated. The appearance of the adolescent acetabular labrum is demonstrated in a pictorial review including MRA and arthroscopic images.
Results: 99 MRA exams were performed during the study time frame. Most common indication for the MRA was hip pain and/or signs of impingement. 78% of the patients who obtained an MRA were female. The average age at the time of imaging was 16 years (from 12 to 22 years). More than 50% of the patients had labral pathology on MRA, and at least 29 underwent arthroscopic repair at our institution. The overall agreement was 79% between MRA and arthroscopic findings, with three false negatives and three false positives. Free marginal Kappa coefficient was 0.59.
Conclusions: A labral tear is a not infrequent cause of hip pain in the adolescent, and an increasing number of MRA exams are routinely being performed. MRA can accurately diagnose the presence of labral pathology and is a useful tool prior to arthroscopy. The pediatric radiologist plays a key role in the diagnosis of labral pathology.