[Clinical experience with a custom-made hip prosthesis developed in Norway]

A custom-made hip prosthesis is developed at St. Olav s Hospital and the Norwegian University of Science and Technology (NTNU) in Trondheim. The purpose was to design an uncemented stem for optimal fit of the proximal femur to achieve secure fixation and optimal strain distribution to the bone. A customized hip prosthesis permits reconstruction of the normal joint mechanism, including reconstruction of leg length, a physiological hip centre and a normal lever arm for the major hip muscles. 6 years of experience with the device at the orthopaedic department at Sørlandet Hospital, Arendal is presented.

43 hips in 37 patients were operated. Median time of observation was 3 years (3 months-6 years). The patients' age was on average 49 years. 70% of the hips had hip dysplasia. The patients were followed prospectively, both clinically and radiologically for up to 6 years (median 3 years).

The operations were performed as planned in all patients with an average operation time of 96 minutes. We have had no re-operations, no post-operative dislocations of the operated hips and no infections. No components have loosened and no patient has complained of thigh pain. One patient had a per-operative femoral fissure that was treated with cerclage, and one patient had an affection of nervus ischiadicus. The mean Harris hip score was 49 pre- and 97 post-operation .

Our experience with the Norwegian custom-made hip prosthesis is promising and confirms the good results from the Trondheim group.