2015 ISAKOS Biennial Congress ePoster #910

Patients with FAI and Hip Microinstability have Better Sports-Specific Outcome Scores than Subjects with FAI without Microinstability

Joshua D. Harris, MD, Houston, TX UNITED STATES
Brian David Lewis, MD, Dayton, OH UNITED STATES
Philip C. Noble, PhD, Houston, TX UNITED STATES

Houston Methodist Orthopedics & Sports Medicine, Houston, TX, USA

FDA Status Not Applicable

Summary: Patients with symptomatic FAI and microinstability have greater subjective and objective sports-specific outcomes versus subjects with symptomatic FAI without microinstability, suggesting that joint hypermobility may allow increased hip motion, permitting greater sports participation.

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Abstract:

Background

Femoroacetabular impingement (FAI) is a common cause of hip pain. Patients with generalized ligamentous laxity and FAI may achieve greater range of motion than patients with FAI without laxity. This extra motion may permit greater participation in competitive sports and higher sport-specific outcome scores. Purpose: To determine if significant differences exist in sport-specific outcome scores between FAI patients with and without microinstability. Methods: A retrospective analysis of prospectively-collected data was performed using a single surgeon's patients over an enrollment period of August 2013 to April 2014. Subjects with symptomatic FAI and labral injury were eligible for inclusion. Cam deformity was defined via alpha angle greater than 55° on Dunn 45° lateral radiographs and loss of anterior head neck offset. Pincer deformity was defined via lateral center edge angle greater than 40°, crossover sign, posterior wall sign, or ischial spine sign. Patients with Tonnis grade 2 or 3 arthrosis were excluded. Patients with dysplasia (lateral center edge angle less than 20 degrees, anterior center edge angle less than 20 degrees, Tonnis angle greater than 10 degrees, or femoral head extrusion index greater than 25%) were excluded. Ligamentous laxity was defined via Beighton score (at least 6 out of 9). Outcome scores collected included Tegner activity score, SF-12 score, Hip Outcome Score (HOS) (Activities of Daily Living subscore and Sports Specific subscore), and iHOT-12 score. Subjects were analyzed at their pre-treatment point in time. Thus, subjects with evaluation and treatment prior to presentation were excluded. Patients with both symptomatic FAI, labral tear, and Beighton 6 or greater were analyzed (Group 1). Patients with symptomatic FAI without laxity (Group 2) were age-, and Tegner-activity score-matched with the laxity cohort. Paired Student's t-test was utilized to compare groups, p<0.05 was deemed statistically significant. Results: Twenty four athletes (mean age 29.0 +/- 10.9 years) were analyzed. More subjects played flexibility sports (yoga, dance, gymnastics) in Group 1 (eight) versus Group 2 (two). Group 1 subjects (Beighton 0.6 +/- 1.8; Tegner 7.5) had symptoms for 2.2 +/- 3.2 years prior to presentation which was not significantly different versus Group 2 subjects (Beighton 7.3 +/- 1.2; Tegner 7.5) (symptoms for 2.3 +/- 2.2 years). Group 1 subjects had a lower BMI (22.3 +/- 3.4 kg/m2) than Group 2 (26.4 +/- 4.5 kg/m2) (p=0.018). Subjects in Group 1 had a significantly greater HOS Sports Specific subscore than those in Group 2 (65% vs 47%; p=0.05) and a significantly greater current level of sports function (71% vs 51%; p=0.05). There was no significant difference (p>0.05) for all other compared outcome scores. Conclusions: Patients with symptomatic FAI and microinstability have greater subjective and objective sports-specific outcomes versus subjects with symptomatic FAI without microinstability. This suggests that joint hypermobility may allow increased hip motion, permitting greater sports participation.