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 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.

[Removal torques of small screws of steel and titanium with different surfaces].

This study was designed to investigate the relationship between metal surfaces and bone holding strength and the safety margin against breakage available in small screws at implant removal. Small cortical bone screws of 1.5 and 2 mm outer diameter (mini-screws) made of stainless steel or commercially pure titanium have been mechanically and chemically treated to give different surface conditions.

A comparative study of the initial stability of cementless hip prostheses.

In the process of prosthetic loosening, the initial motion of the implant relative to the bone is a key element. In order to provide quantitative information, three straight and one curved cementless hip stems were submitted to in vitro tests in autopsy specimens of the femur under dynamic axial and torsional loads with the displacements measured in several directions. The results were compared to those of an additional group of cemented straight stem prostheses providing reference values.

Experimental method for the in vitro testing of the initial stability of cementless hip prostheses.

Micromotions at the interface between bone and prosthesis are believed to induce bone resorption and ultimately lead to loosening of the implant. Thus the initial stability achieved by a hip prosthesis is an important factor for the long-term function of the implant. Knowing the biological consequences of the mechanical conditions, it appears to be mandatory to measure the extent of these three-dimensional movements.