A biomechanical characterization of intramedullary reaming in the human tibia
Puma, Kari L.
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Intramedullary reaming is a technique used in orthopaedic trauma surgical procedures in which the intramedullary canal of a long bone is enlarged and prepared for the implantation of a nail to repair a fracture. Several complications of intramedullary reaming have been described in literature, including elevations in intramedullary pressure and temperature and damage to the blood vessels in the bone. However, the mechanics of intramedullary reaming in the human when performed by a surgeon have not been widely investigated. The purpose of this investigation was to characterize the mechanics of intramedullary reaming, using a novel reamer evaluation tool, performed by two operators of different experience levels. A surgical reaming system was modified with a wireless, custom sensor to measure axial force, torque and RPM of the reamer during use. Ten cadaveric matched tibial pairs were harvested under IRB approval, and one bone of each pair was reamed by the attending orthopaedic trauma surgeon, the other by the orthopaedic surgery resident (PGY-2). Reaming began with a 9mm diameter reamer and proceeded in 0.5mm increments until the declaration of audible chatter, after which reaming proceeded to a maximum of 1.5mm beyond this point. Axial force, torque and reamer displacement were recorded, from which the time to reach the distal end and the mechanical work to reach the distal end were determined. These parameters were compared between operators at the reamer associated with chatter and the maximum reamer size beyond chatter, and also within individual operators to determine how the mechanics changed from initial chatter acknowledgement to the last, largest reamer used. Three matched pairs were excluded from analysis due to unforeseen difficulties during data collection or with the experimental procedure. Analysis revealed that operator mechanics were not statistically different, with the exception of the application of axial load at the maximum reamer size beyond the declaration of chatter. The resident applied more axial force on the reamer than the attending surgeon for the maximum reamer size. For each operator, force, work and time increased from reaming at chatter to the last reamer used. The results of this study suggest that although the reaming procedure is not strongly operator dependent, there is likely to be a mechanical component of clinical concern associated with continued reaming after noticeable initial chatter. Additional studies with larger sample sizes and operator populations are necessary in order to draw further conclusions.