Macroscopic and histological evaluation of the posterior cruciate ligament in arthritic knees

Abstract

The function of Posterior Cruciate Ligament (PCL) in Total Knee Arthroplasty is currently under debate. Supporters of PCL retention suggest better soft tissue balance as well as proprioception, whereas the adversaries have reported an unstable late flexion. Whether the PCL is retained or removed, the results of knee replacement remains the same. The aim of the present study was to look for the morphologic and histological changes in PCL, that aids in assessing its competence, and to compare these with macroscopic changes. A prospective study was performed on 50 osteoarthritic knees. Both the cruciate ligaments were examined macroscopically during Total Knee Replacement surgery, and classified as normal, fatty, mucinous, or cystic. The PCL was also studied and staged histopathologically, and was compared with its macroscopic appearance. On macroscopic examination, fatty type degeneration was the most common type of degeneration in both PCL and ACL, seen in 68% and 56% cases respectively. Histopathologically, majority of the PCLs (52.4%) were in stage 1 of degeneration. 5 PCLs that appeared macroscopically normal showed degeneration microscopically and 8 PCLs that were histologically normal had fatty as well as mucinous degeneration on macroscopic examination.PCL exhibits degenerative and chronic traumatic modifications of different degrees on microscopic examination. These changes cannot be predicted from macroscopic inspection of the knee at the time of surgery. The frequency of these changes suggests that PCLs in an osteoarthritic knee are of varying quality, and this should be considered by the surgeon while selecting the type of knee replacement.