Total hip arthroplasty by a minimally invasive, direct anterior approach.

OBJECTIVE: Implantation of a total hip replacement device through a direct anterior approach to the hip joint with minimal trauma to adjacent tissue.

INDICATIONS: All conventional total hip replacements, irrespective of age and bone quality.

CONTRAINDICATIONS: Destruction of the proximal femur (tumor, fracture). Severe dysplasia and hip dislocation. Morbid obesity (body mass index [BMI] > 30 kg/m(2)) can be a relative contraindication during the learning curve.

SURGICAL TECHNIQUE: Supine position of the patient on the operating table with the possibility of hyperextension in the mid-table in order to facilitate femoral exposure. Anterior incision, 6-9 cm long, starting approximately 2 cm lateral and 5 cm distal of the anterior iliac spine. Incision of the fascia, blunt preparation in the intermuscular space between tensor fasciae latae muscle and sartorius muscle. Excision of the anterior parts of the capsule. Osteotomy of the femoral neck, removal of the head. Reaming of the acetabulum and implantation of the acetabular component. Exposure of the femur by hyperextension, adduction and external rotation of the leg, incision of the posterior capsule for easy anteriorization of the femur. Reaming and implantation of the femoral component.

RESULTS: 116 consecutive hips in 111 patients were operated on between August 2004 and December 2005. 17 patients were excluded due to fracture or severe dysplasia (Crowe 3 and 4). Mean age was 62.5 years (range, 46-84 years), mean BMI amounted to 23.1 kg/m(2) (range, 18.1-37.7 kg/m(2)). The implantation of a total hip replacement device could be accomplished safely in all patients. No severe intraoperative complication requiring a change of the planned procedure or any additional surgical measures was noted. Mean surgical time was 79 min (45-150 min). The operative time was decreasing gradually during the study period. The mean preoperative Japanese Orthopaedic Association (JOA) score of 47.2 points (range, 18-63 points) improved to 92.3 points (range, 67-100 points) at 3 months postoperatively (p < 0.001) and 94.2 (range, 72-100 months) at the latest follow-up at an average of 17 months (range, 9-26 months).