Bone Graft Volume by Reamer Head Size Using the RIA 2

Introduction: The purpose of the study was to quantify the volume of graft that is obtained using sequential upsizing of reamers using the modularity of the second generation Reamer-Irrigator-Aspirator (RIA 2) system and determine any fracture or perforation risk with upsizing. We hypothesize that graft volume may be predicted using radiographic variables that can be measured before reaming. Materials and Methods: Eleven cadaveric specimens were used to evaluate the sequential amount of graft taken using the RIA 2 modular system. Each cadaveric specimen had bone graft harvested from the tibia and femur. Using a radiographic ruler, estimations of the canal size for both the femur and tibia were performed. Average graft volume with SD per incremental increase of reamer was calculated for both the femur and the tibia. Results: There were no perforations of the femur during any reaming. There were 5 perforations or fractures of the tibias during progressive reaming including 3 during the second pass and 2 during the third pass, with a significant increase in perforation in the tibial specimens (P=0.03). There was no significant difference in graft volume after 3 passes from either tibia or femoral harvesting. However, there was a significant decrease in graft volume on the second pass of the femur that was not seen in tibial harvesting (P=0.0013). Discussion: The RIA 2’s reamer head modularity allows multiple passes of the reamer, which gives surgeons the ability to upsize if more autograft is needed. Total autograft volume was similar between the femur and tibia; however, caution should be used in the tibia because of increased perforation risk. Level of Evidence: Level IV—therapeutic study.