Since the concept of severely suppressed bone turnover (SSBT) after long-term bisphosphonate (BPs) use, SSBT have been believed as the major cause of low-energy femoral fractures, which are called atypical femoral fractures. Here we present several cases of stress fractures with bowing femoral shaft deformity, which can be another cause of low-energy femoral fractures in the elderly. From 1998 to 2012, we treated thirteen cases of low-energy fractures of femoral shaft. All cases were females with an average age of 77.0 (67–88) years. Retrospectively, we assessed fracture type, X-ray of contralateral side, bowing deformity of femur, and duration of BPs use.Introduction
Materials and Methods
This study aims to identify the efficiency of biomechanical and bioactive properties of the bovine cortical bone cage treated with conditionally surface demineralization. The procured bovine femoral bones were got rid of lipid, protein, and blood materials by chemical process such as 3% hydrogen peroxide and 70% ethanol. The long shaft bones were cut by band saw. Several bone cages were processed by milling machine. The cortical bone cages were demineralized by 0.6N HCl treatment with various conditions, which were the tendency of HCl treatment time, position, direction. After neutralization with pH 7.0, phosphate buffered saline washing and freeze drying process, the vial vacuum packed bone cages were sterilized by 25kGy gamma irradiation. The SEM and EDS system were proceeded for morphology and Ca content in various layers of bone cage. In vitro test for cell viability and differentiation, extracted supernatant from each bone cage by tissue culture was treated in MC3T3E1 cells. For indentifying releasing materials, the others were carried for quantitative analysis by ELISA. After each conditioned period, mRNA expression was compared by RT-PCR. The axial compression and bending strength were measured by universal testing machine (UTM) for biomechanical property. Between the outer layer and inner layer of bone cage for 2 hour’s HCl, there was concentrated Ca extracted layer. The tendency of Ca content and direction of demineralised treatment had effects on the compression and elastic strength. In vitro test, initial Osteogenic transcription factor’s mRNA expression and quantitative result of releasing material had rewarding regulation by HCl-treatment time and treated direction. Conditionally surface demineralized bone cage had good osteoconduc-tivity and osteoinductivity for spinal interbody fusion.
