O2038 RADIOLOGICAL FINDINGS AND CLINICAL RESULTS OF 102 THRUST PLATE HIP PROSTHESES – A FOLLOW-UP OF 4 TO 10 YEARS

Abstract

Introduction: The Thrust Plate Prosthesis (TPP) was conceived with the aim of loading the proximal part of the femur as physiologically as possible by transmitting the hip joint force directly to the cortex of the femoral neck and, as an extramedullary anchored implant, to preserve bone stock in the proximal femur. 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 7 years. The mean age at operation was 54 years for the men and 47 years for the women. The indications for surgery were coxarthrosis 72%, idiopathic femoral head necrosis 11%, others 17%. Results: Four implants were revised: two because. Radiolgically in 85 implants major contact was maintained between thrust plate and bone, in 10 implants partial contact prevailed, and in only 3 instances did the bone retract from the thrust plate that a gap appeared. Conclusion: Our medium-term results with the TPP are similar to those for conventional prostheses of the stem type. Technical errors during implantation can lead to early failure of the implant. Bone remodelling in the vicinity of the thrust plate is in 85% of the cases as expected from the biomechanical principles. Occasionally, preferential load transfer through remodelled columns of high density trabeculae to the ribs just below the thrust plate, with corresponding retraction of cortical substance nearby, occurs. Revision of a TPP with replacement through one of conventional design is comparable to a primary intervention. The TPP is a prosthesis of the þrst choice when revision is expected.