COMPARISON OF HUMAN, PRIMATE, AND CANINE FEMORA - IMPLICATIONS FOR BIOMATERIALS TESTING IN TOTAL HIP-REPLACEMENT

The canine model remains an animal of choice for determining the effic acy and safety of various materials and designs used in human total hi p replacement (THR). The primate also is used in orthopedic-related re search for studying limb anatomy, gait, and age-related bone loss. In order to better understand the appropriateness of these animal models for human THR, external morphologies of thirty-three adult Caucasian h uman, sixteen adult chimpanzee, and forty-two adult greyhound femora w ere compared using osteometric methods. Measured parameters included a nteversion angle, cervico-diaphyseal angle, femoral head offset in the frontal plane, and anterior bo cv profiles along the femoral diaphysi s. Although some of the measured parameters were approximately similar between species (e.g., mean cervico-diaphyseal angle of humans and ch impanzees), the majority demonstrated morphologic differences that may be biomechanically significant for interpreting stress transfer acros s the hip (e.g., mean anteversion angle and mean normalized femoral he ad offset between species). Additionally, age-related changes in proxi mal femoral morphology and gait pattern, as well as species-related di fferences in local muscle and inertial forces, may result in notably d ifferent loading conditions across the hip joint of each species. Ther efore, discretion must be exercised when evaluating canine or primate THR materials and designs for potential use in the human hip. (C) 1998 John Wiley & Sons, Inc.