Future materials for foot surgery.

Important advances have been made in the development of biomaterials science and engineering for foot surgery over the past four decades. In this paper, implant materials have been separated into two general categories: temporary implants for bone fixation and permanent implants for joint replacement. As presented, however, currently available temporary implants for bone fixation are often left in place permanently whereas, in the long run, permanent implants for joint replacement cannot realistically be expected to last the lifetime of the average-aged patient, and thus are actually only temporary. The benefits and problems of each of these two implant classes were first presented to set the stage for a discussion of possible future directions in the development of new biomaterials that offer the promise of providing improvements for patient care. For bone fixation in foot surgery, the most promising future biomaterials are presented as fully bioabsorbable polymer matrix composites. These implant materials have the potential for development to provide the initial strength and stiffness of currently used metal alloys without concern regarding implant removal. With the development of these materials, clinicians and patients will no longer be forced to choose between the risks of implant retrieval and the risks of leaving the implant behind. Current obstacles that must be overcome before these future materials can be introduced for general clinical use are related to improvements in mechanical property durability and degradation product biocompatibility. For joint replacement, tissue engineered viable biomaterials for permanent articular cartilage replacement are presented as the most important of the future biomaterials. If truly permanent joint replacement materials are to be developed, the implants must be able to regenerate and sustain themselves to permanently retain their properties. Living and sustainable tissues are therefore essential if implant properties are to be permanently maintained, because all nonviable materials are subject to eventual irreversible structural breakdown, degradation, and fatigue. Again, many problems remain to be solved before these envisioned future materials can be brought to accepted clinical use. However, substantial advances have already been achieved and have demonstrated the feasibility of the development of these materials. Biomaterials science and engineering remains a very challenging and exciting field of research and development. As technology advances, the problems that are faced become more complex and, more than ever, now require interdisciplinary cooperation from molecular and cell biologists, biomaterials scientists and engineers, and clinicians. This is especially true in the relatively new field of tissue engineering.(ABSTRACT TRUNCATED AT 400 WORDS)