Femoral component rotation from a total knee prosthesis can be determined by either a measured resection technique or a balanced
gap technique. With the balanced gap implantation technique, femoral component rotation can vary freely within the restrictions
produced by soft tissue structures. Because internal rotation might cause patella problems, the effect of ligament releases
on femoral component rotation in a prospective clinical study was studied. Femoral component rotation was measured intraoperatively
with a tensor applied in flexion at 150 N in 87 knees. Great interpatient variability was found; femoral component rotation,
reference from the posterior condyles, ranged from −4° to 13°. There was no difference in femoral component rotation of knees
with or without ligament releases in extension. However, knees with major medial release had less external femoral component
rotation than knees with minor lateral releases. Preoperative alignment had no influence on femoral component rotation. The
use of the balanced gap implantation technique theoretically will result in a balanced flexion gap, but the amount of femoral
component rotation will be variable owing to patient variability and variation in ligament releases.
Level of Evidence: Level II, therapeutic study. See the Guidelines for Authors for a complete description of levels of evidence.
Each author certifies that he or she has no commercial associations (eg, consultancies, stock ownership, equity interest,
patent/licensing arrangements, etc) that might pose a conflict of interest in connection with the submitted article.