The Effect of Body Mass Index on Outcomes After Hip Arthroscopy for Femoroacetabular Impingement Syndrome: A Matched Analysis With 10-Year Follow-up

Abstract

Background:

Long-term outcomes after hip arthroscopy for femoroacetabular impingement syndrome (FAIS) have been promising, but no studies to date have examined the effect of body mass index (BMI) on 10-year outcome scores and reoperation rates.

Purpose:

To compare outcome scores and reoperation rates between normal-weight, overweight, and obese patients undergoing hip arthroscopy for FAIS at 10-year follow-up.

Study Design:

Cohort study; Level of evidence, 3.

Methods:

Preoperative, 2-year, 5-year, and 10-year scores for patient-reported outcome measures (PROMs) in patients undergoing surgery between January 2012 and June 2014 were collected. These included the Hip Outcome Score–Activities of Daily Living (HOS-ADL), Hip Outcome Score–Sports Subscale (HOS-SS), modified Harris Hip Score (mHHS), 12-item International Hip Outcome Tool (iHOT-12), visual analog scale (VAS) for pain, and VAS for satisfaction. Clinically significant outcomes were also collected including the minimal clinically important difference (MCID) and patient acceptable symptom state (PASS). Patients were stratified into the normal-weight (18.5-24.9 kg/m²), overweight (25.0-29.9 kg/m²), or obese (≥30.0 kg/m²) group and matched in a 1:1:1 ratio, controlling for age and sex. Reoperation-free survivorship was determined.

Results:

A total of 168 patients, with a mean follow-up time of 10.3 ± 0.4 years, who underwent hip arthroscopy for FAIS were included in the study: 56 normal weight, 56 overweight, and 56 obese. While all groups had similar significant improvements in PROM scores by 10-year follow-up (all P < .001), multivariable analysis revealed significant differences in HOS-ADL scores preoperatively (P < .001) and at 2 years (P = .008), 5 years (P = .005), and 10 years (P = .023). The groups differed in mHHS scores at 2-year (P = .006), 5-year (P = .041), and 10-year follow-up (P = .027). All patients, regardless of BMI, had similar achievement rates of the MCID and PASS for all PROMs. Obese and overweight patients had significantly worse rates of total hip arthroplasty (THA)–free survivorship compared with normal-weight patients (80.4% vs 85.7% vs 96.4%, respectively; P = .026).

Conclusion:

There were significant improvements in all outcome scores across all BMI groups by 10 years after the arthroscopic treatment of FAIS. Obese patients tended to have worse PROM scores at most follow-up time points but similar magnitudes of improvement from preoperatively. Obese and overweight patients converted to THA at significantly higher rates compared with normal-weight patients.