Differentially loaded radiostereometric analysis to monitor fracture stiffness: a feasibility study.

Inability to accurately and objectively assess the mechanical properties of healing fractures in vivo hampers clinical fracture management and research. We describe a method to monitor fracture stiffness during healing in a clinical research setting by detecting changes in fracture displacement using radiostereometric analysis and simultaneously measuring applied axial loads. A method was developed for load application, positioning of the patient, and radiographic setup to establish the technique of differentially loaded radiostereometric analysis (DLRSA).