Abstract
Introduction: The non-cemented, extramedullary anchored Thrust Plate Prosthesis (TPP) was conceived as an implant for younger people with osteoarthrosis of the hip. The proximal part of the femur is loaded as physiologically as possible by transmitting the hip joint force directly to the cortex of the femoral neck, enabling the bone stock in the proximal femur to be preserved.
Materials and methods: We prospectively followed-up 102 hip replacements radiologically and clinically in 84 patients (63 men and 21 women) with a mean follow-up time of nine years (6–12 years). The mean age at operation was 54 years for the men and 47 years for the women.
Results: Four implants were revised: two because of an infection and two because of aseptic loosening. In 85 implants major contact was maintained between the thrust plate and bone, in ten implants partial contact prevailed, and in only three instances did the bone retract from the thrust plate so that a gap appeared. The average Harris hip score (HHS) increased from 51 points preoperatively to 96 points postoperatively.
Conclusions: Our long-term results with the TPP are similar to those for conventional prostheses of the stem type. The detected radiological changes normally take place in the first two years after implantation. After the prosthesis is osseointegrated aseptic loosening of the prosthesis is very unlikely. Bone remodelling underneath the thrust plate is in 85% of the cases as expected from the biomechanical principles. These long-term results confirm our encouraging medium-term observations. The TPP is a prosthesis of first choice when revision might be expected, as in the case of younger patients.
Theses abstracts were prepared by Professor Roger Lemaire. Correspondence should be addressed to EFORT Central Office, Freihofstrasse 22, CH-8700 Küsnacht, Switzerland.
