Fig. 3

a LLR (showing only tibia). Point A - a point in the middle of both tibial spine, point B coinciding with depression on dome of talus, line AB - tibial mechanical axis, line CD - A tangential line to the both proximal tibial condyles, Angle ABD is MPTA (88°), meaning proximal tibia 2° varus. b Drawing of planned proximal tibial resection, line AB mechanical axis, line CD is perpendicular to the mechanical axis passing through point A and tangential to unaffected proximal tibial condyle, here in this case lateral tibial condyle. Line EF perpendicular to Line CD and point F is deepest point at margin of medial tibial condyle, length of this line denotes difference between planned thickness of proximal tibial resection, here planned tibial resection was 2 mm more from lateral tibial condyle than medial tibial condyle after removing cartilage from lateral tibial condyle (with cartilage, depth of resection was planned 9 mm from unaffected condyle, lateral condyle in this case). c Intra-operative measurement of thickness of the resected proximal lateral tibia, 8 mm (2 mm more than medial proximal tibial condyle). d Intra-operative measurement of thickness of the resected proximal medial tibia, 6 mm. e Postoperative LLR (showing only knee) illustrating MPTA, angle FEH, 90°, planned tibial component position