EFFECT OF SURFACE-TOPOLOGY ON THE OSSEOINTEGRATION OF IMPLANT MATERIALS IN TRABECULAR BONE

The importance of surface topology and implant material composition on osseointegration in trabecular bone was investigated using three comm ercially used implant materials and surface-texturing procedures which included blasting, high temperature acid etching, and hydroxyapatite (HA) coating. Surface roughness and spacing parameters were measured f or each implant group with a laser interferometric profilometer. Cylin drical implants were press-fit into trabecular bone sites in the knee of mature miniature pigs. After 12 weeks in situ, osseointegration was evaluated by (1) mechanical pushout tests to measure bone-implant int erface strength and (2) quantitative morphometric measurements of the percent implant surface covered by bone. We found that HA-coated impla nts showed superior osseointegration in terms of both pushout failure load and surface coverage by bone measurements. An excellent correlati on (r(2) = .90) was found between the average roughness of the implant surface and pushout failure load. New methods for altering the local topologic and/or chemical state of the implant surface (i.e., by acid etching) may provide an important new avenue of research for improving the osseointegrative properties of orthopedic materials. (C) 1995 Joh n Wiley & Sons, Inc.