Correlation between macroscopic changes of arthrosis and the posterior cruciate ligament histology in the osteoarthritic knee

BACKGROUND: There is ongoing debate about the role of the posterior cruciate ligament (PCL) in total knee arthroplasty. Advocates of PCL retention cite better soft tissue balance and improved proprioception, whereas opponents report late flexion instability. The results of knee replacement are similar whether the PCL is retained or sacrificed. The aim of the present study was to examine the PCL for histological changes that would infer its competence and correlate these with changes easily observed by the operating surgeon. METHODS: A prospective study of 50 osteoarthritic knees was performed. RESULTS: Histology of the PCL showed changes secondary to degeneration and trauma. In most of the ligaments examined, arteriosclerosis and fibrosis were present. Half of the PCL examined showed perineural fibrosis, myxoid change and hyalinization. These changes, although very frequent, did not correlate well to the changes observed in either the anterior or PCL, or in the overall severity of osteoarthrosis. CONCLUSIONS: Posterior cruciate ligaments usually show degenerative and chronic traumatic change of varying degrees on histology. The changes are not predictable from inspection of the knee at surgery. The frequency of these changes suggests that many osteoarthritic PCL are of indifferent quality and the surgeon should consider this when choosing the style of knee replacement.