Abstract
BACKGROUND: Patients undergoing bilateral hip arthroscopy for femoroacetabular impingement (FAI) require weightbearing restrictions that, combined with surgery, may influence muscle mass and bone mineral density (BMD). HYPOTHESIS: After bilateral hip arthroscopy, patients will exhibit changes in biometric data. STUDY DESIGN: Retrospective cohort study. LEVEL OF EVIDENCE: Level 3. METHODS: National Collegiate Athletic Association (NCAA) Division I collegiate athletes undergoing bilateral hip arthroscopy surgery had a dual energy x-ray absorptiometry (DXA) scan preoperatively and at 3, 6, or 12 months postoperatively. Linear mixed effects models assessed change in total body and leg lean and fat mass, and pelvic, spine, and total leg BMD at each timepoint relative to baseline. RESULTS: Significant decreases (n = 18 athletes) in pelvic BMD were seen at baseline (1.40g/cm(2); [95% CI, 1.30, 1.51]); 3 months (1.33g/cm(2) [1.23, 1.43]; P < 0.001), and 6 months (1.33g/cm(2) [1.22, 1.43]; P < 0.001), and spine BMD at 6 months postoperatively (1.43g/cm(2) [1.30, 1.52]; 1.38g/cm(2); [1.29, 1.47]; P = 0.02). Lower extremity and total body fat mass were increased at 3 months (6881 g; [4932, 8829]; 7757 g [5801, 9713]; P < 0.01), (19,565 g; [13130, 25999]; 21,467 g; [15012, 27922]; P = 0.02), whereas total body lean mass was decreased at 3 months (66,736 g; [58,265, 75,207]; 64,978 g; [56,492, 73,464]; P = 0.04). Results at 12 months were not significantly different from baseline. CONCLUSION: In NCAA Division I collegiate athletes who underwent bilateral hip arthroscopy for FAI, pelvic and spine BMD was decreased up to 6 months after surgery when compared with presurgery measurements, but no decrease was observed after 1 year. Clinicians should be aware of the potential implications of decreased bone mass up to 12 months postsurgery. CLINICAL RELEVANCE: Understanding changes in body composition and BMD postoperatively may help to guide rehabilitation management and injury risk assessment.