Total knee arthroplasty for arthritic patients in whom all the conservative measures have been exhausted, is an excellent procedure if proper attention paid to the patient selection.
As total knee arthroplasty is a surface replacement within the existing soft tissue sleeve, it functions within normal anatomic and physiologic boundaries. Recent information on the outcome of minimally invasive procedures suggests the reduction of the surgical trauma and offers early improvement and faster rehabilitation. This effect levels off after 3 months to a result similar to that in patients who have had a standard exposure. This means factors other than the exposure and extensor mechanism violation are involved in the reduced functionality after total knee arthroplasty.
Various factors are associated with the onset and progression of osteoarthritis. These include genetic factors, age, sex, obesity, occupation, abnormal loading of the joint in kneeling, squatting and cross-legged sitting.
In 99% of the arthritic knees requiring arthroplasty including rheumatoid, posterior cruciate ligament was found to be intact. The intact PCL may have to sacrificed in rare instances such as in the knees with severe angular deformity requiring an extensive release on the concave side of the deformity, where the intact posterior cruciate ligament can act as a tether and hinder proper balancing of medial and lateral structures.
36 patients were evaluated preoperatively and postoperatively using the knee society score. Translation of the proximal tibia posteriorly in flexed knee is visualised radiologically in sacrificed group, indicating posterior cruciate ligament’s function as a restraint to translational displacement.
Significantly, greater improvement in flexion from preoperative to most recent follow-up assessment were seen in patients in the posterior cruciate retaining group compared to the sacrificed group. This is due to femoral roll back defined as the posterior shift of the tibiofemoral contact areas which are well visualized radiologically after flexing the knee.