The effect of distal femoral bone cut on flexion gap in cruciate retaining total knee arthroplasty -A cadaveric study-

INTRODUCTION: Proper bone cut and soft tissue balancing are the most critical procedures in total knee arthroplasty (TKA). A gap balancing technique is commonly used in TKA to create an equal extension and flexion gap. However, obtaining a flexion gap sufficiently large for the extension gap in cruciate retaining (CR) TKA is sometimes difficult and the flexion gap in CR TKA tends to be smaller in comparison to the extension gap. To address this, several studies have proposed ways to manage the tight flexion in CR TKA, including posterior cruciate ligament (PCL) release, additional posterior tibial slope, and downsizing of femoral component. Among the multiple factors affecting the balance of the flexion and extension gap, we focused on the fact that a larger distal femoral bone cut produces a larger extension gap (in other words, a smaller flexion gap). We wanted to clarify how the amount of distal femoral bone cut affects the balance of the flexion and extension gap. The purpose of the present study was to evaluate the effect of the size of the distal femoral bone cut on the flexion gap in CR TKA using cadaveric knees.