Mechanical Strength of Radius Fracture Repair Using an Expanding Cement

Introduction Displaced fractures of the distal radius are typically repaired by either closed reduction and casting or open reduction with internal plate fixation. This treatment dichotomy fails for elderly patients, where risks associated with open surgery outweigh benefits, and malunions after closed reduction frequently result in deformity. A need exists for minimally invasive fixation which provides the benefits of internal fixation without associated surgical risks. Efforts have been made to utilize materials such as acrylic cements (PMMA) and hydroxyapatite based cements (HAC) to anchor the trabecular bone on either side of a fracture. Despite promising results, the approaches were plagued by material limitations including lack of bone ingrowth and integration (PMMA) and inadequate mechanical properties (HAC) [1]. A castor oil based polyurethane cement may prove a suitable alternative as it demonstrates mechanical properties akin to cancellous bone, porosity requisite for bone ingrowth and integration, and an opportunity for enhanced mechanical fixation through volumetric expansion during curing. The objective of this work was to experimentally evaluate the mechanical strength obtained in radius fracture repair with a castor oil based polyurethane material and compare the results to similar fixation with PMMA. We hypothesized that the castor oil based cement would provide superior mechanical strength relative to a similar PMMA repair.