The effects of mechanical factors on bio-compatibility tests.

Evaluation of materials for bone and joint replacement has led to contradictory results in a number of cases: some researchers have reported the formation of good load-bearing bone structures along the surface of a particular material, e.g. dense, high strength Al2O3-ceramics, others found the same material encapsulated by soft tissue. Considering the results of various animal experiments and the evaluation of clinical follow-up studies, it can be shown that many of these conflicting observations are due to different biomechanical conditions at the site of examination. Failure to consider the local load situation at the interface between the implanted specimen and the bone tissue can lead to misleading statements about the possible applications of a material.