A minimally invasive approach for total hip arthroplasty does not diminish early post-operative outcome in obese patients: a prospective, randomised trial.

Purpose: The benefits of minimally invasive surgical techniques in total hip arthroplasty (THA) are well known, but concerns about applying those techniques in obese patients are controversial. We prospectively compared patients with increased body mass index (BMI ≥ 30) undergoing THA with normal weight patients.

Methods: A total of 134 patients admitted for unilateral THA were randomised to have surgery through either a transgluteal or a minimally invasive approach (MicroHip). In each group a BMI ≥ 30 was used to define obese patients. Pre- and early post-operative demographics, intraoperative data, baseline haematological values, hip function (Harris Hip Score, Oxford Hip Score) and quality of life (EQ-5D) were assessed with follow-up at three months.

Results: Duration of surgery, blood loss, C-reactive protein levels, radiographic measurements and complication rates were comparable in all groups. There was a tendency for lower serum creatine kinase levels in the MicroHip group. Intraoperative fluoroscopic time and dose area products were significantly elevated in patients with a BMI exceeding 30 regardless of the approach used. Time points of mobilisation, length of hospital stay and functional outcome measurements were similar in the different weight groups.

Conclusions: Our data suggest that obese patients gain similar benefit from MicroHip THA as do non-obese patients. The results of this study should be further investigated to assess long-term survivorship.