Key issues involved with the use of miniature specimens in the characterization of the mechanical behavior of polymeric biomaterials--a review.

This article is arranged in three parts. In the first, a brief history of the use of miniature specimens for characterizing the mechanical behavior of materials in general is given. In the second part, several trends in literature reports of small punch and small shear punch tests of ultra-high-molecular-weight polyethylene and acrylic bone cement specimens are examined critically. In this exercise, special attention is paid to one test metric; namely, the work to failure [which is the area under the punch load (P) versus punch displacement (Delta) plot up to the failure point]. In the third part of the article, seven key issues in this field are discussed. In each case, the gaps in the current knowledge base are pointed out. Among those issues are determination of sensitivity of test results to test variables, development of methods for converting P-Delta results to bulk material properties, and constitutive modeling of the mechanical behavior of a polymeric biomaterial, under both small punch and small shear punch loading. Copyright 2002 Wiley Periodicals, Inc. J Biomed Mater Res (Appl Biomater) 63: 455-466, 2002