Low Body Mass Index and Obesity associated with Lower Outcomes Following Hip Arthroscopy for Femoracetabular Impingement


      The purpose of this study was to comparepatient reported outcomes for patients undergoing primary hip arthroscopy for femoroacetabular impingement(FAI) based upon their BMI.


      738 patients (Female 353, Male 385) with average age 36 (18-70) diagnosed and treated for primary FAI met the inclusion criteria. Patients were included if they underwent hip arthroscopy with labral repair and femoral and/or acetabular osteoplasty. Any patient that had previously undergone hip surgery, arthroscopic or open were excluded. Patients were divided into four cohorts based upon world health organization BMI classification: 1.< 18.5 kg/m2, 2. 18.5 -24.9 kg/m2 , 3. 25.0 – 29.9 kg/m2, 4. > 30 kg/m2.


      Mean weight was 74.0 kg (44 – 144 kg). Mean Height was 174.5 cm (104.1 – 213.4 cm). Mean BMI was 24.1 kg/m2 (15.1 – 44.1 kg/m2). Groups 1 (18:1) and 2 (276:181) were predominantly female while Groups 3 (180:49) and 4 (23:10) were predominantly male. BMI was correlated with age (rho=.10; p=0.006), lateral joint space (rho=.0.09; p=0.016), alpha angle (rho=0.08; p=0.0280), flexion (rho=-0.253, p<0.001), abduction (rho=-0.144; p<0.001), adduction (rho=-0.1;p=0.0150 and internal rotation (rho=-0.27; p<0.001). BMI did not correlate with pre-op or post-op outcome scores (HOS ADL, HOS Sport, MHHS, WOMAC, and SF12). Comparison between the 4 groups showed significant differences in range of motion (Table 1). Pre-op MHHS, and HOS ADL were significantly different between groups, with Group 2 and 3 having the highest scores. Post-op HOS sport was also significantly different between groups.


      When a patient's BMI is categorized according to WHO guidelines, obese patients have lower preoperative status and outcomes, patients in the overweight category do not. In addition, patients in Group 1 had the lowest post-op outcome scores of all groups. This highlights the possibility that nutritional balance for patients is more than their BMI.