Patients with coxarthrosis and proximal femoral deformity experience problems with total hip arthroplasty. A custom-made prosthesis or a proximal osteotomy is required for such cases, and these also increase the rate of complications. The purpose of this study was to evaluate the results of the thrust plate prosthesis (TPP) in patients with deformity of the proximal femur.
Fifteen patients (7 females, 8 males) with a mean age of 56.4 years (range 19-75 years) at the time of the surgery were included in the study. The etiology was traumatic coxarthrosis in 12, and nonunion of a femoral neck fracture with osteonecrosis of the femoral head in the remaining three. While the femoral component was a third-generation TPP in all patients, the acetabular component was a Protek expansion cup in 12, and a cementless standard cup in three patients. All operations were performed through a Hardinge approach. Patients were followed up for at least 3 years (range 36-116 months) and evaluated clinically with the Harris Hip Score.
The mean preoperative Harris Hip Score increased from 51.2 (range 15-79) to 92.7 (range 60-100) at the latest assessment. In two cases, loosening of the femoral component was observed in zone 3, both 12 months postoperatively. One was replaced by an intramedullary prosthesis, and the other was asymptomatic.
TPP is a good alternative for patients with malformations of the proximal femur. The use of TPP avoids technical difficulties and a custom-made prosthesis.