Instruments and methods for flexion gap adjustment

Abstract

A flexion gap instrument is configured to mate with a ligament tensioning tool, such as known distraction devices and pivoting knee balancers. The instrument facilitates making A/P resections in the femur for placement of a femoral prosthesis component to maintain an optimum symmetric flexion gap, which will avoid the risk of medial or lateral laxity in flexion, instability of articulating component dislocation. The instrument includes a base that is configured to sit within the ligament tensioning device, and a vertically extending upstanding portion that is configured to mate with a cutting block or other knee arthroplasty instrument that must be positioned relative to the distal end of the femur. The upstanding portion includes a measurement plate that bears a scale indicating a flexion gap distance. The scale can be used to orient and align the cutting block in its proper position relative to the distal end of the femur, and to orient the cutting block parallel with the tibial plateau with the ligaments properly and equally tensed. In certain embodiments, a leaf spring can be incorporated into the upstanding portion to help support the cutting block and provide a mechanism for temporarily positioning the cutting block on the flexion gap instrument without the need for additional or supplemental locks.