CLINICAL RESULTS OF ANATOMICAL RESTORATION OF HIGH HIP DISLOCATIONS WITH SUBTROCHANTERIC SHORTENING OSTEOTOMY AND HIDROXIAPATITE COATED TOTAL HIP PROSTHESIS

Abstract

Total hip arthroplasty in adult patients with congenital high dislocation of the hip (DDH, Crowe type IV) presents many challenges. Various reconstruction methods including iliofemoral distraction lenghtening and custom made prosthesis have been reported but the standard technique for dealing with this problem is femoral shortening with a subtrochanteric osteotomy. There are many reports of different subtrochanteric osteotomy techniques with satisfactory results.

Since 1999, we have been using the same anatomic reconstruction principles with a proximally hydroxyapatite coated cementless stem. Surgical technique on the femoral side comprises a short oblique subtrochanteric osteotomy and excision of a segment as indicated for a safe reduction. This usually requires extensive soft tissue releases of the pelvifemoral muscles. Gluteus maximus, tensor fascia latae and adductors are routinely released. However, we don’t want to do any more release until it is absolutely necessary. Preserving the attachment of the abductors and iliopsoas are important for eventual functional outcome. They help stabilizing the joint, avoid limping and promote hip flexion during the initial swing phase of the gait and stair climbing. We never resect neither osteotomize the trochanters and, if a release is unavoidable, it is performed proximally. Thus, it is possible to preserve a complete segment of the proximal femur with a soft tissue envelope. This segment allows for better bone stock, prompt healing, reliable proximal fixation through the intact medial calcar and, avoids the complications of trochanteric osteotomy. With this technique we have not observed a femoral revision for any reason in 101 high dislocated hips (in 84 patents), since 1999. Compared with other techniques for arthroplasty in patients with developmental hip dysplasia, this surgical technique has a better functional outcome and a low prevalence of revision.

To evaluate the effect of this reconstruction on gait parameters we analyzed the gait cycle in 17 hips in 10 patients before and after the the total hip arthroplasty and compared it with the patients with hip arthroplasty due to primary osteoarthritis. Our aim is to determine the restoration of normal anatomy in DDH patients compared to the patients with total hip arthroplasty but a normal hip anatomy. As a result we have demon-strated that our technique restores normal gait parameters by improving walking speed, lengthening step-stride length, correcting hip and knee flexion and ankle equinus, improving hip and knee stiffness during gait and helps to restore normal gait parameters