Strontium ranelate improves implant osseointegration

INTRODUCTION: Endosseous implantation is a frequent procedure in orthopaedics and dentistry, particularly in the aging population. The incidence of implant failure, however, is high in situations where the bone at the site of implantation is not of optimal quality and quantity. Alterations of bone turnover and changes in intrinsic bone tissue quality have potentially negative effects on optimal osseointegration. Strontium ranelate, which acts on both resorption and formation, and improves biomaterial properties, is hypothesized to improve osseointegration and this hypothesis was tested here. MATERIALS AND METHODS: Titanium implants were inserted into the proximal tibias of thirty 6-month-old Sprague-Dawley female rats. During the 8 weeks following implantation, animals received orally strontium ranelate (SrRan) 5 days a week (625 mg/kg/day) or saline vehicle. Pull-out strength, microCT and nanoindentation were assessed on the implanted tibias. RESULTS: SrRan significantly increased pull-out strength compared to controls (+34%). This was associated with a significant improvement of bone microarchitecture around the implant (BV/TV+36%; Tb.Th+13%; Conn.D+23%) with a more plate-shape structure and an increase in bone-to-implant contact (+19%). Finally, strontium ranelate had a significant beneficial effect on parameters of bone biomaterial properties at both cortical (modulus+11.6%; hardness+13%) and trabecular areas (modulus+7%; hardness+16.5%). CONCLUSIONS: SrRan is an antiosteoporotic agent that increased mechanical fixation of the implant. The improvement of pull-out strength was associated with an improvement of implant osseointegration with both a positive effect on bone microarchitecture and on bone biomaterial properties in the vicinity of the implant. These current results may support potential benefits of strontium ranelate in orthopaedic and dental surgery to enhance osseointegration