Abstract
Introduction
The effect of each step of medial soft tissue releases on the external rotation angle of the femoral component was assessed during posterior stabilized total knee arthroplasty (PS-TKA) with modified gap control technique.
Methods
Consecutive 840 knees were assessed. During PS-TKA, medial soft tissue release was done to obtain rectangular gap in extension using tensors/balancers. The deep fiber of medial collateral ligament (MCL) was released in all cases. No more release was done in 464 knees. Only anterior fiber of superficial MCL was released in 49 knees, and only posterior fiber of superficial MCL was released in 129 knees. Both fibers were released in 169 knees. Additional pes anserinus was released in 29 knees. Rotation angle of the femoral component was decided based on the flexion gap angle. The angle was compared among the five groups.
Results
The average external rotation angle of the femoral component was 4.8°, 5.3°, 4.6°, 4.3°, 4.1°, respectively. The external rotation angle in knees after release of superficial MCL fibers and more was statistically significantly smaller compared to that in knees without release (P<0.001).
Conclusion
Releases of MCL superficial fibers and more in order to obtain soft tissue balancing in extension significantly widened the medial joint gap in flexion and reduced external rotation angle of the femoral component.
