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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.(More)
The satisfactory long-term radiographic appearances with the use of the collarless, smooth, polished, tapered stem encourage its continued use. With the same stem geometry shortly to become available with interchangeable heads, the capacity for the surgeon to change the bearings when polythene wear starts to become marked should address what certainly will(More)
The appearance and mechanism of femoral stem wear was studied in 172 retrieved femoral components, of which 74 stems had been stable in vivo. Macroscopic, microscopic, and nano-level scales of examination were used. Loss of stem surface in response to micromotion (wear) was found to affect 93% of stems. However, changes were frequently difficult to see with(More)
The effects of 12 clinically relevant variables upon the basic mechanical properties of acrylic cement are reported. Attention is drawn to the facts that these variables may at times coexist to lead to serious reductions in the strength of the cement, and that the operating surgeon may exercise a substantial influence on the effective mechanical properties(More)
We report the results of simple laboratory experiments which showed that bleeding pressures known to occur at the bone surface during total hip arthroplasty may compromise the integrity of the bone-cement interface and the cement itself. Such undesirable effects can be prevented by maintaining adequate pressure on the cement until its increased viscosity(More)
Evidence from studies on migration raises serious doubts regarding the part played by fatigue failure of acrylic bone cement in the genesis of aseptic loosening of the components of total hip arthroplasties. Moreover, the viscoelastic properties of cement raise serious doubts concerning the relevance of conventional laboratory fatigue studies to the in vivo(More)
Bone necrosis adjacent to self-curing polymethylmethacrylate is a matter of accepted fact. Among the possible causes are mechanical and vascular damage from the preparation of the bone cavity, chemical damage from the monomer and free radicals in the cement dough, and thermal damage from the heat of polymerisation, occurring in this order. Consideration of(More)
We present a long-term follow-up report of the results of the original Exeter polished cemented stems inserted between November 1970 and the end of 1975 at our institution by surgeons of widely differing experience using crude cementing techniques. The results of this series were reported in 1988 (Fowler et al. Orthopaedic Clinics of North America.(More)
The mechanical properties of a number of commercially available bone cements have been investigated. Tests were carried out on specimens in compression, in bending and in tension. Using the compression test as a standard, the effects of the following variables were studied: the addition of antibiotics, strain rate, environmental temperature, and age. It was(More)