Mechanical changes in macro-porous calcium phosphate ceramics after implantation in bone

Abstract

The authors have developed an experimental device to assess the mechanical property changes of porous calcium phosphate ceramics after implantation in bone. Cylinders of a macroporous biphasic ceramic were implanted in the femurs of rabbits (6 x 6 mm) and beagle dogs (6 x 9 mm) for the compression test and in the tibiae of rabbits (5 x 5 mm) to characterize the physico-chemical changes. The compressive strength of the material before implantation was 2·6 MPa and it increased after implantation ( P < 0·001). It doubled after one week in rabbit femurs (5·9 MPa) and was multiplied by 2·5 after three weeks in dog femurs (6·8 MPa). Infrared and histological analyses showed that physicochemical modifications had occurred at the same time as the increase in the compressive strength. New components had appeared in the ceramic after implantation: organic phases by bone ingrowth, particularly collagen matrix, biological apatites and water.