We report the results of using impacted cancellous allografts and cement for fixation of the femoral component when revision arthroplasty is required in the face of lost bone stock. In 56 hips reviewed after 18 to 49 months there were few complications and a majority of satisfactory results with evidence of incorporation of the graft. Further study and review are necessary, but the use of the method appears to be justified.

Four cases are described of localised endosteal bone lysis in the femur occurring in association with cemented femoral components that were not obviously 'loose' radiologically. In each, the area of lysis was shown at operation to be related directly to a region in which there was a local defect in the cement mantle surrounding the stem. Via the space between the stem and cement, such defects provide a route through which the contents of the joint cavity may reach the endosteal surface of the femur, subsequently leading to localised bone lysis, and later to frank loosening.

W e describe our experience with the implantation of 325 Exeter Universal hips. The fate of every implant was known. The procedures were undertaken by surgeons of widely differing experience. At follow-up at 12 years, survivorship with revision of the femoral component for aseptic loosening as the endpoint was 100% (95% CI 98 to 100). Survivorship with revision of the acetabular component for aseptic loosening as the endpoint was 96.86% (95% CI 93.1 to 98.9) and that with any reoperation as the endpoint 91.74% (95% CI 87.7 to 95.8). No adverse features have emerged as a consequence of the modular connection between the head and neck of the implant.

No abstract

The shear strength of trabecular bone from the femur has been studied. In general, the strongest trabecular bone is found close to the cortico-cancellous junction, though its shear strength depends also on the relationship of the trabeculae to the plane of shear. Some factors affecting the shear strength of the cement-bone interface have been investigated. In vitro, maximal cement-bone interface shear strength is obtained by exposing and thoroughly cleaning strong trabecular bone, and then forcing onto it under pressure low viscosity cement.

No abstract

We report the histology of a femur retrieved 3.5 years after a cemented revision of a hip replacement in which impaction allografting had been used to fill two large cortical defects. The allograft chips had largely been replaced by viable cortical bone, and the interface between cement and tissue resembled that seen after primary cemented arthroplasty.

In a prospective, randomised controlled trial, the efficacy of the A-V Impulse System in the prevention of deep-vein thrombosis was investigated in 84 patients who had undergone total hip replacement. The incidence of venographically proven, and clinically significant postoperative deep-vein thrombosis was 40% in the control group and 5% in the treatment group (p less than 0.001). No adverse reactions were recorded.