[Treatment of femoroacetabular impingement using a minimally invasive anterior approach].

OBJECTIVE: Treatment of femoracetabular impingement to prevent or delay the development of secondary osteoarthritis of the hip. Improvement of the mechanical limitation of the range of motion of the hip joint. Pain-free movement of the hip.

INDICATIONS: Femoroacetabular impingement including a cam impingement, a pincer impingement, as well as mixtures of both types. Osteoarthritis of the hip joint grades 1-3 according to Kellgren induced by a femoroacetabular impingement.

CONTRAINDICATIONS: Pincer impingement with the necessity of an osteotomy in acetabula malaligned in retroversion. Severe osteoarthritis grade 4 according to Kellgren. Hip infection.

SURGICAL TECHNIQUE: Supine position of the patient. Longitudinal incision of 5-6 cm in line with the medial border of the anterior superior iliac spine at the level of the greater trochanter, two thirds cranially and one third distally of the tip of greater trochanter. Minimally invasive anterior approach in a modified technique of the Smith-Petersen approach with cutting of the fascia and preservation of the lateral femoral cutaneous nerve running between the two layers of the fascia. Blind preparation between the sartorius muscle and the tensor fasciae latae muscle. Preparation and T-shaped opening of the joint capsule in the direction of the capsule fibers and the anterior iliofemoral ligament. Removal of additional bone mostly in the ventral area of the femoral neck with angled and straight chisels. Using different positions of the leg helps to reach the more medial and lateral areas of the femoral neck. A trimming of the acetabulum with or without refixation of the labrum in the anterior and anterocranial acetabular rim is also possible. Documentation using fluoroscopy. Wound closure.

POSTOPERATIVE MANAGEMENT: Prophylaxis of deep venous thrombosis. Early functional mobilization with unlimited range of motion of the hip joint. The amount of weight bearing is influenced by the amount of bone resection during trimming. In most cases, full weight bearing is possible. In cases of extensive bone resection (more than one fourth of the femoral neck diameter), gradual increase of weight bearing over 6 weeks.

RESULTS: After a follow-up of 15.5 +/- 6.8 months, 65 patients (20 female, 45 male; 70 hip joints) aged 40.2 +/- 11.3 years showed an improvement of the Oxford Hip Score from 34.3 +/- 9.8 points preoperatively to 16.3 +/- 11.0 points and of the WOMAC (Western Ontario and McMaster Universities) Score from 60.8 +/- 23.1 points to 84.0 +/- 15.1 points at the latest follow-up examination. The impingement test was negative in all cases. In twelve cases, a temporary hypesthesia of the cranial innervation area of the lateral femoral cutaneous nerve was reported.