Synthesis and Characterization of Bone Ingrowth Associated with Bone Cement Co-Polymerized with a Biodegradable Material

To alleviate fixation-related problems that are associated with cemented total hip arthroplasty (THA), the ingrowth of bone into the mantle of porous bone cement was investigated as a means to promote attachment between the host bone and the implanted cement. We co-polymerized poly methyl methacrylate (PMMA) and poly(L-lactic acid) (PLLA) by introducing an unsaturated alkene (vinyl) group into the PLLA, and the powdered vinyl–PLLA (v-PLLA) was co-polymerized with liquid methyl methacrylate (MMA) to form biodegradable bone cement. Biodegradation of the bone cement was simulated by prolonged immersion in phosphate-buffered saline (pH 7.4). Degradation of cement specimens that contained v-PLLA was slower than cement that contained only unmodified PLLA. This result indicated that the initial fixation period of the v-PLLA-containing bone cement was sufficiently long to allow for the ingrowth of bone into the cement mantle, which was confirmed by scanning electron microscopic examination of v-PLLA-containing bone cement that was implanted into the femurs of rabbits. We conclude that the biomechanical properties of v-PLLAcontaining bone cement make this material suitable for clinical applications such as THA.