Influence of the Reamer-Irrigator-Aspirator diameter on femoral bone strength and amount of harvested bone graft – a biomechanical cadaveric study

Abstract

BackgroundTreatment of large bone defects is still related to unsolved problems in orthopaedic trauma surgery. Minimally invasive intramedullary reaming with the use of the Reamer-Irrigator-Aspirator (RIA) device allows autograft harvesting of large bone graft amounts from the medullary canal of the femur. The aim of this study was to investigate the influence of RIA diameter on femoral bone strength and amount of harvested bone graft in a human cadaveric model. MethodsForty-five pairs human cadaveric femora were randomized to 3 paired groups with 15 pairs each. One femur of each pair was reamed with RIA at a diameter of either 1.5 mm (group 1), 2.5 mm (group 2) or 4.0 mm (group 3) larger than its isthmus, whereas its contralateral femur was left intact without reaming. The amount of harvested bone graft was determined for each specimen and all femora were destructively tested in internal rotation under 750 N axial compression to calculate their torsional stiffness and torque at failure. ResultsSignificant reduction in torsional stiffness was detected after reaming in group 3 (p = 0.03) in contrast to groups 1 and 2 where no such significant reduction was observed (p ≥ 0.34). Torque at failure was significantly reduced after reaming in all 3 groups (p ≤ 0.04). Collected bone graft amount in group 3 was significantly bigger compared to groups 1 and 2 (p ≤ 0.04). ConclusionsReaming with RIA diameter of 4.0 mm larger than the isthmus of the femur seems to influence considerably its torsional stiffness, however, it allows harvesting of a significantly bigger bone graft amount.