The importance of surface topology and implant material composition on osseointegration in trabecular bone was investigated using three commericially 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 for each implant group with a laser interferometric profilometer. Cylindrical 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 interface strength and (2) quantitative morphometric measurements of the percent implant surface covered by bone. We found that HA-coated implants showed superior osseointegration in terms of both pushout failure load and surface coverage by bone measurements. An excellent correlation (r2 = .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.