CORA ABSTRACT #II - 5

THE EFFECT OF THE POSTERIOR CRUCIATE LIGAMENT ON SOFT-TISSUE BALANCE IN TOTAL KNEE ARTHROPLASTY

R. El-Hawary

S. Roth

J.C. Harwood

G.K. King

J. Johnson

D. Chess

It believed that PCL-sacrifice during TKA will increase the flexion gap and, therefore, decrease compressive loads at 90^o. Our purpose is to investigate in vitro soft tissue balance between PCL-retaining and PCL-sacrificing TKA.

Cruciate-retaining TKA was performed on 12 cadaveric knees. A validated tibial load cell recorded compressive forces at varying flexion angles prior to ligamentous balance, after MCL and PCL balance, and after arthroscopic PCL resection.

No significant differences were found in lateral compartment forces.

There were no differences in medial compartment load between pre-balance and PCL-retained at 0, 30, and at 60^o and between PCL-retained and PCL-sacrificed at 0, 90, or 100^o. Medial compartment force at 30^o: PCL-retained 42.7N, PCL-sacrificed 29.9N*. 60^o: PCL-retained 40.7N, PCL-sacrificed 28.1N*. 90^o: Pre-balance 38.3N, PCL-retained 19.3N*, PCL-sacrificed 19.7N. 100^o: Pre-balance 37.2N, PCL-retained 16.6N*, PCL-sacrificed 14.2N. * denotes p<0.05.

After balancing the PCL, a significant decrease in medial forces was noted at 90^o and 100^o. Further improvement at these angles was not observed with PCL-sacrifice. At mid-flexion, however, PCL-sacrifice resulted in decreased medial forces. As expected, no differences were seen in extension.

As compared to a well-balanced PCL-retaining TKA, PCL-sacrifice does not offer improved balance at 90^o, but it does decrease medial compartment forces at mid-flexion.