Imageless navigation assisted total knee arthroplasty with comprehensive gap balancing in medial osteoarthritic varus knees with anatomic variations.

This study retrospectively compares the postoperative alignment of imageless navigation assisted (INA) total knee arthroplasties (TKAs) using comprehensive gap balancing with that of conventional TKAs in 72 medial osteoarthritic varus knees with coronal plane anatomic variations of the distal femur and proximal tibia. The navigation group showed significantly lower postoperative differences in the mechanical axis (MA) of the lower limb (p = 0.003), with fewer outliers (p = 0.03), better femoral component positioning relative to the MA (p = 0.02), and less difference between the weight-bearing MA of the lower limb and the MA of the femur (p = 0.003) and tibia (p = 0.005). INA comprehensive gap balancing TKA provides a better correction of leg alignment and better orientation of components with respect to the MA in medial osteoarthritic varus knees with lateral bowing of the femoral shaft and external rotation of the femur and/or proximal tibia vara, thus indicating the superiority of this approach over the conventional technique in such situations.