Does axial limb rotation affect the alignment measurements in deformed limbs?

The long-term outcome of total knee arthroplasty and femoral or tibial oste otomy is related to the ability of the surgeon to achieve the desired align ment based on preoperative planning. This study evaluates the effect of axi al rotation on measured tibiofemoral angles and the angle formed between th e anatomic and mechanical axes of the femur in lower extremities with valgu s and varus deformities, A comparison study of the measured tibiofemoral an gles indicated a statistically significant effect in models with severe val gus or varus deformity when rotated 10 degrees internally or externally. In the second part of the study, the measured angle between the anatomic and mechanical axes of the femur never varied by more than 1 degrees, despite a 40 degrees are of rotation. The results of the study indicate the tibiofem oral angle measurements are more sensitive to axial limb rotation in lower extremities with valgus or varus deformity than are normally aligned limbs, In preoperative planning of total knee arthroplasty, the measured angle be tween the anatomic and mechanical axes of the femur is less effected by lim b rotation, regardless of the degree of valgus or varus deformity.