2015 ISAKOS Biennial Congress ePoster #908

Does FAI Contribute to the Development of Labral Tears

Karen K. Briggs, MPH, MBS, Vail, CO UNITED STATES
Marc J. Philippon, MD, Vail, CO UNITED STATES
Steadman Philippon Research Institute, Vail, CO, USA

FDA Status Not Applicable

Summary: This study demonstrated that patients with alpha angles >55 degrees are at greater risk of having a labral tear identified at arthroscopy.

Abstract:

Purpose

Several studies have documented that patients with labral tears of the hip have high alpha angles which are indicative of cam impingment. The purpose of this study was to determine if preoperative alpha angle predicts the presence of labral tears arthroscopy.

Methods

A prospective data registry was queried for all patients who had preoperative alpha angle measurements from MRI and documentation of labral status at arthroscopy. Revision hip arthroscopies were excluded. 1422 hip arthroscopies in 1391 patients met the criteria. Average age was 31.6 (range 14 to 71). This study was IRB approved. To reduce intra and inter-observer error, all alpha angles were measured on MRI by one musculoskeletal radiologist. Alpha angle >55 degrees was defined as diagnostic for cam impingement for this study. All arthroscopies were performed by one surgeon.

Results

Average alpha angle was 63.8 (range 34 to 98). 1070 hips had alpha angle >55 degrees. 1352 hips had labral tears. Average size of labral tear was 30mm(range 5mm to 80mm). Labral tear size did correlate to alpha angle )r=0.202;p<0.01). The average alpha angle in patients with labral tears was 64 degrees and in patients without labral tears the average was 60 degrees(p=0.017). 1026 hips with alpha anlge >55 had labral tears and 43 did not have labral tears. The relative risk of a labral tear if you have alpha angle >55 was 14.1 [95%CI: 10.2 to 20.2]. The positive predictive value was 96% [95%CI: 95.1 to 96.6].

Conclusions

This study demonstrated that patients with alpha angles >55 degrees are at greater risk of having a labral tear identified at arthroscopy. In addition, hips with labral tears had significantly higher alpha angles than those without tears. This positive association between alpha angle and labral tears add further evidence that FAI is a major contributor to the development of labral tears.