Effect of balanced gap total knee arthroplasty on intraoperative laxities and femoral component rotation.

The gap technique could lead to undesirable rotation of the femoral component in some knees. Using a navigation system, femoral component external rotations and varus-valgus laxities at 0° and 90° of flexion were measured intraoperatively in 44 patients. Significant improvements were observed at a minimum follow-up of 4 years with regard to clinical and radiologic outcomes. The balanced gap technique in total knee arthroplasty provided good intraoperative alignments and laxities of knees at 0° and 90°. However, increased femoral component external rotation was found to be correlated with increased varus alignment at 90° of knee flexion. This study shows that excessive external rotation of the femoral component during flexion gap balancing using the balanced gap technique in total knee arthroplasty can be avoided by additional soft tissue balancing guided by navigation.