[Total hip replacement in presence of acetabular dysplasia type II according to the AAOS classification.].

GOAL OF SURGERY: Incorporation of the acetabular cup in ideal position in patients with a primary dysplastic acetabulum. Two thirds of the surface of the cup must be covered by bone. INDICATIONS: Joint replacement in patients with acetabular dysplasia type II according to the AAOS classification. CONTRAINDICATIONS: Presence of acetabular dysplasia types I and III according to the AAOS classification. PREOPERATIVE WORK UP: Radiographic measurement of the acetabular depth and width using templates. POSITIONING AND ANAESTHESIA: Supine, affected side of pelvis slightly elevated. General or spinal anaesthesia. Special set of instruments mandatory. SURGICAL TECHNIQUE: Insertion of an acetabular cup through a lateral approach. Reaming of the acetabulum and filling of the defect under compression with a mixture of autogenous, morcellized bone from the resected femoral head and fibrin glue. Coverage of the transplanted bone with a pedicled capsular flap. POSTOPERATIVE MANAGEMENT: Phlebitis prophylaxis. Walking with 2 forearm crutches on the first postoperative day. Removal of stitches after 10 days. Thereafter gradual increase of weight bearing (10 kg every second day, use a bathroom scale to check loading). Once full weight bearing and full muscle control have been reached, use of 1 crutch is allowed. Radiographic control after 6 weeks, 3,6 and 12 months and yearly thereafter. POSSIBLE COMPLICATIONS: Perforation of the bony acetabulum. Fracture of the anterior or posterior acetabular rim. Thrombophlebitis, lung embolism, infection and/or periarticular ossification.
RESULTS: Between 1986 and 1994 the technique has been used in 140 hips with congenital dysplasia (type II according to the AAOS classification) and secondary osteoarthritis. 132 hips were regularly assessed and the mean of follow-up was 6.2 years (1 to 9 years). The mean age of the mostly female patients was 48 years (28 to 62 years). Only porous surfaced metallic cups without cement were used. The following complications were observed: thrombophlebitis 1, superficial infection 1, transient paresis of the fibular nerve 1 and transient irritation of the femoral nerve 3 (see Table 2). Additional complications such as thigh pain, periarticular ossification and resorption of the bone graft are listed in Table 3. Complete bony incorporation of the bone grafts was seen in 122 hips. Resorption up to 8 mm occurred in the remaining 10 hips.