The minimally invasive anterolateral approach combined with hip onlay resurfacing.

OBJECTIVE

Minimally invasive anterolateral approach in hip resurfacing with complete preservation of muscular integrity.

INDICATIONS: Primary or secondary osteoarthritis of the hip.

APPROACH: None. Onlay implant: Females>55 years with osteoporosis. Males>60 years with osteoporosis. Severe varus deformity (CCD [collodiaphyseal] angle<100 degrees). History of metal allergy. Clinically relevant renal insufficiency. Radiologic appearance of avascular necrosis stage 3 and 4 according to Ficat. Femoral head cysts>1 cm in diameter.

SURGICAL TECHNIQUE: Supine position with possible overextension of the hip, longitudinal incision along the intermuscular septum and blunt intermuscular dissection between gluteus medius and tensor fasciae latae, partial resection of the anterior capsule and anterior dislocation of the hip with complete proximal release of the capsule. Dislocation of the femoral head and dorsal positioning, reaming of the acetabulum to implant the cementless acetabular component, exposition and reaming of the femoral head in extension/adduction and external rotation, implantation of the cemented onlay endoprosthesis.

POSTOPERATIVE MANAGEMENT: Prophylaxis of thromboembolism and periarticular ossification. Rehabilitation with weight bearing as tolerated starting on the day of surgery, ergometer training from day 4 after surgery.

RESULTS

31 patients with osteoarthritis underwent onlay resurfacing via a minimally invasive approach. The Harris Hip Score improved from 43.9 to 97.1 at 12 months after surgery. Adverse events such as fracture, dislocation, nerve or muscle lesions did not occur, and clinically significant thromboembolism or infection was not observed.