- Discussion:
- posterior capsular ligament has three parts;
- one overlies each femoral condyle and a third, shorter section passes between them;
- these three parts normally limit extension provided that the depths of the prosthetic surfaces and the cement are exactly correct;
- stability in full extension is fundamental to the success of knee replacement;
- if fixed flexion is present after operation, muscle effort is wasted;
- if too much hyperextension is allowed, knee feels unstable & flexor and extensor muscles act
together to maintain a normal posture;
- uses of the posterior capsular ligaments to define exact position of
femoral component
ensures stability in full extension;
- new
tibial component is cemented in place & uncemented femoral trial component used to ensure that sufficient bone has
been removed from the end of the femur to allow a few degrees of hyperextension;
- ligaments should be taut and stable in extension;
