Stiffness measurements to assess healing in bone transport: a preliminary report

Little is known about the pattern of healing in patients undergoing bone transport for limb reconstruction. We evaluated the possibility of using bone stiffness for assessing healing in 8 consecutive patients treated with the Orthofix limb reconstruction system for non–union or bone loss. Six procedures were successful in achieving restoration of leg length and healing at both the docking site and the callotasis segment. Two procedures were unsuccessful, resulting in below–knee amputation. Of the six successful procedures, five were followed with bending stiffness measurements, while one patient was temporarily lost to follow–up. In all cases, the docking site took longer to heal than the callotasis segment. Patterns of healing of the callotasis segment were similar to that found in limb lengthening, and the docking site healed with a rate similar to that found in severe tibial fractures. The stiffness value proved to be a clinically useful, objective measure of healing in bone transport. A level of 15 Newton metres/degree (nm/d) allowed safe fixator removal in these cases.