Mismatch between femur and tibia coronal alignment in the knee joint: Classification of five lower limb types according to femoral and tibial mechanical alignment

Reasons for dissatisfaction with total knee arthroplasty (TKA) include unequal flexion or extension gap, soft tissue imbalance, and patella maltracking, which often occur with mismatch between femoral and tibial coronal bony alignment in the knee joint or extremely varus or valgus alignment.