The direct anterior approach: initial experience of a minimally invasive technique for total hip arthroplasty

BACKGROUND: Less invasive approaches for hip arthroplasty have been developed in order to decrease traumatisation of soft tissue and shorten hospital stay. However, the benefits with a new technique can be at the expense of a new panorama of problems. This manuscript describes, with emphasis on postoperative complications, our experience from the first 200 cases of unilateral hip replacement using the direct anterior minimally invasive (MIS) approach. METHODS: A straight incision in front of the greater trochanter was used and the tensor muscle was approached subfascially and retracted laterally. The joint was opened and the femoral head was removed. Usually excellent acetabular exposure was obtained. In order to get access to the proximal femur, the hip capsule was released posterolaterally so that the femur could be lifted using a special retractor behind the tip of the trochanter. After insertion of the prostheses, the wound was closed using running sutures in the fascia overlying the tensor, sub- and intracutaneously. RESULTS: There was a small influence of BMI on the duration of surgery, and obese patients tended to have the cup positioned at a higher degree of deviation. There were in total 17 complications of which 5 necessitated revision surgery; 3 peroperative femoral fractures and 2 dislocations. Another 4 dislocations were treated with closed reduction and did not recur. 3 cases of nerve injury were noted, all resolved within 12 months. Three cases of DVT were diagnosed as well as 2 cases of postoperative infection; none of these led to chronic disability. CONCLUSIONS: The technique is perhaps more technically demanding than the lateral approaches used today due to the somewhat limited surgical exposure. Morbidly obese or very muscular patients as well as patients with a short femoral neck or acetabular protrusion can represent particular problems. Our results indicate that there are certain risks when adopting this procedure but the complications noted are avoidable.