PAPER 11: FRACTURES CAUSE SIGNIFICANT OSTEOPENIA AT THE IPSILATERAL LIMB

Abstract

Introduction: It has recently been observed that around the site of a fracture bone loss of up to 10% can occur during the healing process. We hypothesized that trabecular bone around the site of a diaphyseal fracture is considerably diminished during the course of fracture healing and that this loss can be partly compensated by antiresorptive therapy.

Methods: 45 Sprague Dawley rats were randomly divided into 3 groups: Ovariectomy (OVX), sham operation (NON-OVX) and OVX with bisphosphonate (ibandonate) treatment (OVX+BIS). All animals received a standard closed mid diaphyseal fracture of the left femur fixed with an intramedullary pin. After 4 weeks of healing both femurs were excised and scanned with Micro CT to analyze bone architecture in the femoral head.

Results: There was significant osteopenia due to ovariectomy (p< 0.001). BV/TV was reduced by 30%. The fracture itself induced a similar osteopenia at the ipsilateral femur. In OVX animals the fracture induced osteopenia was potentiated by ovariectomy and amounted in a total bone deficit of 60% compared to healthy cancellous bone. Bisphosphonate treatment significantly reduced both the OVX and fracture induced osteopenia.

Discussion: A fracture leads to significant localized osteopenia at locations adjacent to the fracture site. Our findings suggest that the increased risk of secondary fractures after a first osteoporotic fracture might be related to the loss of trabecular bone caused by the fracture healing process. Therefore it is important to consider prevention measures for osteoporosis during the course of fracture healing in osteoporotic patients