The purpose of this prospective study was to evaluate the influence of BMI on the feasibility of minimally invasive total hip arthroplasty (THA).

This prospective study included 86 patients (88 THA) operated on via a single minimally invasive incision (7 cm) using an anterior approach on Judet's orthopedic table. Mean age was 63.7 years and mean BMI was 25.8. Forty-one patients were classified in group I (BMI<25) and 46 in group II (BMI ≥ 25). Perioperative data, pain, postoperative blood loss, duration of the procedure, and length of the incision were noted. All patients were reviewed at three months and radiographic analysis was performed to asses the position of the socket and the quality of the cementation.

BMI did not appear to be a strict contraindication for a minimally invasive procedure. Nevertheless, bleeding and operative duration were statistically correlated with BMI (ε=4.28 and ε=2.66). Extension of the wound noted at the end of the procedure in patients with BMI ≥ 25 (t=5.01) may have resulted from greater pressure on the skin and soft tissue due to stronger traction and more abrasion of the skin edges by reamers and rasps. Such damage may lead to more wound complications even though in our experience there was no statistical difference. On the other hand, socket position and cementation did not appear to be correlated with BMI.

Results concerning duration of the procedure, bleeding, hospital stay and rate of complications are contradictory in the literature. At the same time, criteria for patient selection remain unclear. It thus appeared to be of interest to determine whether BMI was a good criterion to determine the feasibility of THA via a minimally invasive procedure.

BMI appears to be a good criterion to evaluate the risk of wound complications after minimally invasive surgery. On the other hand, other criteria must be found since BMI does not evaluate muscle mass which seems to be of major concern in minimally invasive procedures.