The Total Hip Arthroplasty For Adult Patients With Development Dysplasia Of The Hip

Objective: To investigate some issues about THA for adult patients with DDH and its therapeutic efficacy as well.Methods: From Mar.2002 to Mar.2007, total hip arthroplasties were performed for 23 patients (23 hips) with DDH. There were 7 males and 16 females with an average age of 40.6(ranging from19 to 70). Based on the classification of Crown, there were 7 in typeⅠ, 8 in typeⅡ, 5 in typeⅢand 3 in typeⅣ, all of which belong to the unilateral THA. The operation was through acetabular lateral-posterior approach. After articular capsule base was reached, the lower limb was placed in rotated externally position to enlarge the exposed area. Then, the contractured articular capsule was totally cut and the tendon and fascia were released, including the attachment point of the iliopsoas on the lesser trochanter so that femoral head was exposed. According to the bone cutting line designed before the operation, the bones were cut in the position of femoral neck on the lesser trochanter. The hyperplasia fiber and fat tissue were clear off in the real acetabulum. On the basis of measured outcome before the operation, acetabular saws, ranging from small to large, were applied with the inclination angle between 10～20°and the anteversion angle between 40～45°to construct the acetabulum and thus the acetabular rotation centre was reconstructed.In addition to the standard procedure of THA, the methods of restoring normal level of rotation center of the hip included structural bone autografting and medializalion of the cup. The methods of limb length restoration included carefully preoperative planning and intraoperative soft tissue release.Antibiotics were routinely used to prevent infection and a week long of anticoagulant therapy for preventing deep vein thrombus in lower extremities after the operation. 3 days after operation, patients began the hip functional exercises.6 weeks after operation, patients got out of bed, walked with double crutches and conducted isokinetic strength training under the guidance of doctor. After 6 weeks, patients can gradually come to full weight-bearing. For patients with femur osteotomy, only the postoperative X-ray 12 weeks later showed the osteotomy had got good bone union could they walk with single crutch. For patients with acetabulum structural bone grafting, the weight bearing should be extended to 3 months later after operation. The criteria for therapeutic effects assessment include: the comparison of patients in this group before and after operation in line with Harris score system; the comparison of the lower limb length before and after operation; acetabular prosthesis, femoral component positioning and grafting bone positioning judged by the postoperative X- ray.Results: In this group, the operation time was 90-180 min (mean 120 min) and the average blood transfusion was 800 ml. All patients had primary healing. No infection, vascular nerve injury and dislocation were observed. After osteotomy, Bones were reuninoned in 8-12 weeks after operation. Two patients had split fracture in proximal femur during operation, and received fixation with steel wire cerclage and bone paste packing.In all cases, the rotating centers of hip were returned to normal. With regard to acetabular reconstruction, 11 cases received THA (7 typeⅠand 4 typeⅡ), including 5 cases of biological fixation and 6 with bone cement; 5 cases had structural bone grafting in acetabular (4 TypeⅡ, 3 typeⅢ,1 typeⅣ) including 6 cases of biological fixation and 2 with bone cement;4 cases had ingression of acebular rotating center (2 typeⅢand 2 typeⅣ),including 3 cases of biological fixation and 1 with bone cement. Eight patients used non-bone cement prothesis, 16 bone cement prosthesis. The preoperative length difference of lower limbs was 1-5.0cm, while it is 0-1cm after operation. All patients underwent soft tissue release to different extents. Two cases of typeⅣhad osteotomy of middle and distal femur with plate internal fixation. One patient, who had bone extrophy in proximal femur previously, received osteotomy and reshaping of remarkable deformity, then fixed with bone cement femur prothesis. All patients were followed up except one died 2 years later after operation. The average follow-up time was 38 months (ranging from 1 to 6 years). The pain in hip joint was relieved. Joint function returned to normal. Patients can walk independently and afford daily activities. Harris scores increased from 39.2 (25-68) before operation to 87.2 (78-96) in final follow up. X-ray showed no changes of acetabular bone and femur prosthesis. All bone graft in acetabular superior margin survived. No graft absorption was observed.Conclusion: To achieve a satisfactory therapeutic efficacy with THA for adult patients with DDH,firstly, the doctor should design the proper treatment scheme and thoroughly consider the surgical indication before operation. Secondly, in operation, the doctor should also pay great attention to the replacement of prosthesis in real acetabulum, the proper treatment of acetabbular and femur abnormalities, the release of soft tissue around hip joint, and the correct choice of prosthesis so as to recover the limb length and improve the function of hip joint.