Preclinical Trial of a Novel Surface Architecture for Improved Primary Fixation of Cementless Orthopaedic Implants.

Background: A new surface architecture for cementless orthopaedic implants (OsteoAnchor),which incorporates amultitude of tiny anchor features for enhancing primary fixation,was tested in an ovine hemi-arthroplasty pilot study. Methods: Test animalswere implanted with a hip stem component incorporating the OsteoAnchor surface architecture produced using additive layermanufacturing and control animalswere implanted with stems containing a standard plasma sprayed titanium coating.Findings: Intra-operative surgeon feedback indicated that superior primary fixation was achieved for theOsteoAnchor stems and rapid return to normal gait and load bearing was observed post-operation. Following a 16-week recovery time, histological evaluation of the excised femurs revealed in-growth of healthy bone into the porous structure of the OsteoAnchor stems. Bone in-growth was not achieved for the plasma sprayed stems. Interpretation: These results indicate the potential for the OsteoAnchor surface architecture to enhance both the initial stability and long term lifetime of cementless orthopaedic implants.