Despite the number of publications which have dealt with posterior cruciate ligament (PCL) retaining total knee arthroplasty, few studies have addressed the histology of the PCL. Based on these, the use of some predictive factors for lesions of the PCL has been suggested, as a decisive argument to substitute the ligament or not. The objective of this study was to assess the value of some predictive factors, based on objective findings. We performed histological analysis of 434 PCLs removed during total knee arthroplasty for osteoarthritis. Fifty-eight percent of these ligaments presented histological lesions. The degree of preoperative knee deformity, the intra-operative appearance of both cruciate ligaments, and gender were found to correlate with the severity of the microscopic lesions of the PCL. No such correlation was found with age nor with the type of knee deformity. Calcium pyrophosphate deposits were a frequent and potentially pejorative finding in the PCLs from osteoarthritic knees. Due to their poor sensitivity and specificity, the criteria suggested in previous studies to decide on preserving or substituting the PCL appeared fairly unreliable.