Development of Strontium-Impregnated Bioabsorbable Bone Screw for Fracture Fixation in Osteoporotic Bone

Osteoporosis is demonstrated to influence the bone healing process as well as the bone fracture fixation. Therefore, the treatment for osteoporosis is important for bone fracture treatment. In this study, the calcium phosphate ceramic (CPC) was used as a carrier to deliver anti-osteoporosis regimen (Strontium Ranelate). The Sr-CPC was mixed with poly(caprolactone) (PCL) in different weight ratio to develop a bioabsorbable bone screw. Relative to metal implant, this Sr-impregnated bone screw with less rigid strength shall benefit fracture fixation in osteoporotic bone. The mechanical strength, microstructure, degradation time, and drug releasing pattern of Sr-CPC/PCL composite will be demonstrated. The addition of pore-forming agents will be considered to increase the pore size, porosity, and drug releasing rate. Human osteoblasts will be used and cultured on the Sr-CPC/PCL composite to estimate the material-mediated cytotoxicity, mRNA expressions, and protein productions. The constituents of Sr-CPC/PCL composite will be determined depending on the in vitro study, and Sr-CPC/PCL screws will be fabricated. The ovariectomized rabbit model will be used as an osteoporosis model, and the standard bone fracture will be created. The Sr-CPC/PCL screws will be implanted into the distal femur of rabbit. μ-CT will be used to analyze the bone quality of osteoporotic rabbits received Sr-CPC/PCL screws. The interface between Sr-CPC/PCL screw and bone tissue will be examined by histology. The purpose of this study is to evaluate the effects of Sr-CPC/PCL bone screw on fracture fixation in osteoporotic bone.