THE STRENGTH OF BONE-METAL BLOCK FOR DIFFERENT TYPES OF IMPLANTS SURFACES UNDER THE CONDITIONS OF NORMAL BONE AND OSTEOPOROSIS IN RATS

Abstract

Fixing the acetabular component of prosthesis in the conditions of osteoporosis and changes in acetabulum anatomy is an actual problem of modern orthopedics. The goal: to perform a comparative analysis of the strength of bone-metal block for the different type of implant surfaces in the conditions ofnormal bone and in the simulation of osteoporosis in rats. The methods: experimental studies of femur strength were carried in 60 laboratory animals (rats). The animals were divided into two groups of 30 animals each: I — relatively healthy, II — osteoporosis induced by ovariectomy. 6 subgroups were formed in each group of animals. Implants of such differentmaterials as porous titanium, tantalum porous Trabecular Metal (Zimmer), titanium coated with Gription (DePuy), Stiktite (Smith & Nephew), Trabecular Titanium (Lima), Tritanum (Stryker) were used to fill a hole-like defect in distal metaphysis of femur. The animals were taken out of experiment 14 days after implanta­tion and biomechanical investigation was performed to assess the strength of operated and contralateral femurs. Longitudinal axial load using a metal rod was applied to femoral head. Load value gradually increased to complete destruction of anatomical specimen and measured. The results: femurs with implants from porous tantalum Trabecular Metal and Stiktitewith stood the maximum load in the conditions of normal bone density. Specimen of femurs with implanted porous titanium (the most weak) and tantalum Trabecular Metal (the most solid) composed separate subsets in the conditions of simulated osteoporosis. The conclusions: the comparative analysis of biomechanical investigation revealed that bone with implants from porous tantalum withstands the maximum breaking load in the conditions of normal and osteoporotic bone.