Bone Preserving Prosthesis Thrust Plate Prosthesis THA
Eighty-three patients (87 hips) suffered from osteoarthritis of the hip joint (OA group), 79 patients (92 hips) from osteonecrosis of the femoral head (ON group). The mean age at surgery was 55 years in the OA group and 47.4 years in the ON group. The mean follow-up period was 97 months in the OA group and 104 months in the ON group. For these patients, we evaluated the results clinically and radiographically.
The thrust plate hip prosthesis(TPP) is a bone-reserving prosthesis for cementless fixation at the metaphysis of the proximal femur. We retrospectively evaluated the results of 162
patients (179 hips) who underwent hip arthroplasty using TPP.
The mean Merle d’Aubigne’s score improved from 8.2 to 16.9 in the OA group and from 9.1 to 16.6 in the ON group at the final follow-up. Early mechanical loosening of TPP was observed in two hips of OA and one hip of ON. In one patient of ON, bilateral TPPs had to be removed five years postoperatively because of infection. Two female patients with ON suffered from a spontaneous femoral fracture below the tip of the lateral plate. Kaplan-Meier survivorship using TPP removed for any reason as the end point was 97.7% in the OA group and 90.3% in the ON group after 13 years.
Because of its bone-preserving model, it is a useful implant for young people who are compelled to have a hip replacement arthroplasty. In recent years, the focus is on metal-on-metal hip implant, which is a surface replacement and capable of bone-preservation. However, reports are emerging from many facilities about the side effect inducing pseudo-tumor due to be considered caused by metal wear. TPP has no such side effect, and is a very safety hip joint.