Cancellous bone response to strontium-doped hydroxyapatite in osteoporotic rats

The objective of this study was to investigate cancellous bone response to strontium-doped hydroxyapatite (SrHA) in ovariectomized (OVX) rats.

Hydroxyapatite (HA) and 10%SrHA (HA with 10 mol% calcium substituted by strontium) implants were prepared and characterized by scanning electronic microscopy (SEM), energy dispersive microanalysis (EDX) and X-ray diffraction (XRD). Twelve weeks after bilateral ovariectomy, 20 rats randomly received HA or 10%SrHA implants in the right distal femur, with 10 animals in each group. Eight weeks after implantation, specimens were harvested and analyzed by micro-computed tomography (micro-CT) and histology.

Compared with HA, 10%SrHA raised the percentage bone volume by 42.6%, bone-to-implant contact by 47.1%, mean trabecular number by 27.3%, mean trabecular thickness by 31.5% and mean connectivity density by 37.4%, while it decreased mean trabecular separation by 20.1% in micro-CT evaluation. 10%SrHA also increased the bone area density by 47.6% in histological analysis.

With the HA implants as controls, the 10%SrHA implants were shown to increase bone density and bone-to-implant contact, and improve trabecular architecture in the vicinity of implant surfaces.