A reduced‐modulus acrylic bone cement: Preliminary results

Excessive local contact stress is implicated as an important factor in the initiation of the loosening process after total joint arthroplasties. A reduced‐modulus acrylic bone cement, which decreases the bone‐cement interface stresses, was developed to test this hypothesis. The formulation consists of butylmethacrylate beads, having a glass transition temperature of 27°C in a methylmethacrylate matrix. This cement, polybutylmethylmethacrylate (PBMMA), has an elastic modulus one‐eighth that of standard PMMA bone cement, 0.27 vs. 2.1 GPa, at body temperature. In vivo use in a pilot study using the sheep total hip arthroplasty model shows a reduction in the rate of loosening of femoral components when compared both radiographically and mechanically with PMMA controls.