THE RELATIVITY OF BIOCOMPATIBILITY - A CRITIQUE OF THE CONCEPT OF BIOCOMPATIBILITY

The concept of biocompatibility of the materials used in surgical reco nstruction of joints, ligaments, and tendons is controversial, as evin ced by the conflicting definitions proposed by the many authors who ha ve studied the host reaction to the presence of implants and their bre akdown products. We propose that biocompatibility of contemporary medi cal implants is not a property of the chemical composition of the biom aterials but depends rather on their physical attributes. The histolog ical reaction patterns of tissue to the presence of polyethylene in di verse physical states are described. The inflammatory response evoked by the implants is laudable in so far as it precedes and accompanies t he adequate tissular incorporation of the devices used. On the other h and, the granulomatous reaction induced by small, irregularly shaped a nd edgy breakdown products adversely affects the life span of the impl ants. Thus the manner in which the host handles the biomaterials is de termined primarily by the physical state of the biomaterials (rather t han their chemical composition), which in turn determines the success or failure of reconstructive surgery. It logically follows that biocom patibility constitutes a relativistic concept.