Introduction

Over-tightening screws results in inadvertent stripping of 20% of cortical bone screws. The current method of “two-fingers tight” to insert screws relies on the surgeon receiving torque feedback. Torque, however, can be affected by screw pitch, bone density and bone-thread friction. An alternative method of tightening screws is the “turn-of-the-nut” model, commonly used in engineering applications. In the “turn-of-the-nut” method, nuts used to fasten a joint are rotated a specific amount in order to achieve a pre-specified bolt tension. When applied to orthopaedics, bone assumes the role of the nut and the screw is the bolt. The screw is turned a set angular rotation that is independent of torque feedback. Potentially the “turn-of-the-nut” method provides an easier way of screw insertion that might lessen inadvertent screw stripping. The purpose of the current study was to use the “turn-of-the-nut” method to determine the angular rotation that results in peak plate compression and peak screw pullout force.