Purpose: The aim of this study was to evaluate the outcomes and early complications of obese patients who underwent total hip arthroplasty for osteoarthritis via an anterolateral approach in the supine position (ALS-THA) and compare these outcome with of a matched control group of non-obese patients.
Patients and methods: Thirty-one hips in 28 patients with obesity (BMI ≧ 30 kg/m2) were included in this study. As a control group, 31 hips of 31 patients with a normal weight (BMI between 20 and 25 kg/m2) were matched based on age, sex, and laterality. Clinical evaluations using the Merle d'Aubigne and Postel hip score, radiological evaluations and perioperative complications were compared in two groups.
Results: There were no significant differences between the groups in the operative time, period of hospitalization, clinical hip score, or cup positioning, although the position of the cup tended to deviate from the optimal safe zone in the obese compared with non-obese group (32.3 and 16.1%, respectively). There was no infection, dislocation, nerve palsy, or life-threatening event in either group. The rate of avulsion fractures of the greater trochanter in the obese group was 3 times higher compared to that in the non-obese group.
Conclusions: As the clinical outcome of ALS-THA for the obese group is not inferior to that for the non-obese group, obesity is not considered to be a contraindication for ALS-THA. However, obesity increases the risk of intraoperative greater trochanteric fracture. Thus, surgeons should be particularly careful when manipulating the femur in this class of patients, who should be informed of this risk.
Keywords: Anterolateral approach in supine position; Greater trochanteric fracture; Obesity; Total hip arthroplasty.