Posterior cruciate ligament avulsion in total knee arthroplasty.

An anatomic study was outlined to measure the strength of the posterior cruciate ligament after total knee arthroplasty. This interest was precipitated by a patient whose posterior cruciate ligament ruptured 6 months after a total knee arthroplasty. Six unembalmed knee specimens (three bilateral) were mounted in a mechanical tension-testing machine, and proximal tibial total-knee bone cuts were performed at successive 2 to 3 mm depths. At each level, the ligament was tested at physiologic tension. The posterior cruciate ligament failed at 7 to 10 mm of bone resected, with an average failure at 8.6 mm.