Bone ongrowth and mechanical fixation of implants in cortical and cancellous bone

William Robert Walsh,Per Morberg,Matthew Henry Pelletier,Vedran Lovric,Tian Wang,Nicky Bertollo,William Chase Harington Parr,Dario Bergadano

doi:10.1186/s13018-020-01696-5

Abstract

BackgroundWhat is the right surface for an implant to achieve biological fixation? Surface technologies can play important roles in encouraging interactions between the implant surface and the host bone to achieve osseointegration. Preclinical animal models provide important insight into in vivo performance related to bone ongrowth and implant fixation.MethodsA large animal model was used to compare the in vivo response of HA and plasma-sprayed titanium coatings in a well-reported adult ovine model to evaluate bone ongrowth in terms of mechanical properties in cortical sites, and histology and histomorphometry in cortical and cancellous sites at 4 and 12 weeks.ResultsTitanium plasma-sprayed surfaces outperformed the HA-coated samples in push-out testing in cortical sites while both surfaces supported new bone ongrowth and remodeling in cortical and cancellous sites.ConclusionsWhile both HA and Ti plasma provided an osteoconductive surface for bone ongrowth, the Ti plasma provided a more robust bone-implant interface that ideally would be required for load transfer and implant stability in the longer term.

Highlights

Implant stability remains the foundation to which clinical success can be built upon for any implant in bone be it a dental implant [1, 2] or joint replacement system [3,4,5]
Differences in the surface topologies can be seen for both groups at various magnifications up to × 100,000 with the globular appearance of calcium phosphate as well as the lack of distinct surface features for the Ti plasma coating beyond × 5000 magnification (Fig. 2)
The FTIR spectra (Fig. 3) of HA standard and the HA coating collected from the implant revealed the typical spectra of calcium phosphate with major corresponding mineral peaks of phosphate (PO43−) and carbonate (CO32−) identified

Summary

Introduction

Implant stability remains the foundation to which clinical success can be built upon for any implant in bone be it a dental implant [1, 2] or joint replacement system [3,4,5]. Osseointegration, where a direct living bone-implant interface [1, 2] is achieved through bone ongrowth to a surface or ingrowth into porous domains, dictates load transfer [6], bone remodeling, and long-term fixation. Choosing the “best” surface needs to consider design, manufacturing, cleaning, sterilization, mechanical properties, biocompatibility, implantation, and in vivo response. This is a big task for all stakeholders involved in arthroplasty with the aim of achieving the best clinical outcome. Methods: A large animal model was used to compare the in vivo response of HA and plasma-sprayed titanium coatings in a well-reported adult ovine model to evaluate bone ongrowth in terms of mechanical properties in cortical sites, and histology and histomorphometry in cortical and cancellous sites at 4 and 12 weeks. Conclusions: While both HA and Ti plasma provided an osteoconductive surface for bone ongrowth, the Ti plasma provided a more robust bone-implant interface that ideally would be required for load transfer and implant stability in the longer term.

Methods

Results

Conclusion