Effects of Increasing Tibial Slope on the Biomechanics of the Knee

Ten cadaveric knees were studied using a robotic testing system using three loading conditions: (1) 200 N axial compression; (2) 134 N A-P tibial load; and (3) combined 200 N axial and 134 N A-P loads. Resulting knee kinematics were determined before and after a 5-mm anterior opening wedge osteotomy. Resulting in situ forces in each cruciate ligament were determined.

Tibial slope was increased from 8.8 +/- 1.8 degrees to 13.2 +/- 2.1 degrees, causing an anterior shift in the resting position of the tibia relative to the femur up to 3.6 +/- 1.4 mm. Under axial compression, the osteotomy caused a significant anterior tibial translation up to 1.9 +/- 2.5 mm (90 degrees ). Under A-P and combined loads, no differences were detected in A-P translation or in situ forces in the cruciates (intact versus osteotomy).