Errors in visual estimation of flexion contractures during total knee arthroplasty

Figure 1 Intraoperative use of the knee flexion contracture measuring device.

Figure 2 The effect of posterior slope of the proximal tibial cut on the measurements with the study device. If the femoral and tibial components were both placed perpendicular to the long axis of each bone as pictured, then the study device would indicate the presence of a 5° flexion contracture. However, if the proximal tibia was cut with 5° of posterior slope, it would give the false impression that full extension had been achieved as the two inclinometers would be parallel.