Following endosteal uncemented orthopaedic device implantation, the initial implant/bone interface retains spaces and deficiencies further exacerbated by pressure necrosis and resultant bone resorption. This implant-bone space requires native bone infill through the process of de novo osteogenesis. New appositional bone formation on the implant surface is known as contact osteogenesis and is generated by osteogenic cells, including skeletal stem cells (SSCs), colonising the implant surface and depositing the extracellular bone matrix. Surface nanotopographies provide physical cues capable of triggering SSC differentiation into osteoblasts, thus inducing contact osteogenesis, translated clinically into enhanced osseointegration and attainment of secondary stability. The current study has investigated the in vitro and in vivo effects of unique nanotopographical pillar substrates on SSC phenotype and function. Adult human SSCs were immunoselected, enriched using STRO-1 antibody and cultured on control and test surfaces for 21 days in vitro. The test groups comprised Ti-coated substrates with planar or modified surfaces with nanopillar. Osteoinductive potential was analysed using qPCR and immunostaining to examine gene expression and protein synthesis.Background
Methods
In 2012, the National Joint Registry recorded 86,488 primary total hip replacements (THR) and 9,678 revisions (1). To date aseptic loosening remains the most common cause of revision in hip and knee arthroplasty, accounting for 40% and 32% of all cases respectively and emphasising the need to optimise osseointegration in order to reduce revisions. Clinically, osseointegration results in asymptomatic stable durable fixation of orthopaedic implants. Osseointegration is a complex process involving a number of distinct mechanisms affected by the implant surface topography, which is defined by surface orientation and surface roughness. Micro- and nano-topography levels have discrete effects on implant osseointegration and yet the role on cell function and subsequent bone implant function is unknown. Nanotopography such as collagen banding is a critical component influencing the SSC niche in vivo and has been shown to influence a range of cell behaviours in vitro (2,3). We have used unique fabricated nanotopographical pillar substrates to examine the function of human bone stem cells on titanium surfaces. To investigate the effect of nanotopographical cues on adult skeletal stem cell (SSC) fate, phenotype and function within in-vitro environments.Background
Aim
