Histopathological analysis of the posterior cruciate ligament in primary osteoarthritis.

BACKGROUND: According to some authors, the indication of an arthroplasty maintaining the posterior cruciate ligament (PCL) demands adequate structural preservation and proprioceptive function of this ligament. The nervous fibers contained in the synovial neurovascular bundle (NVB) around the PCL are involved in proprioception. A study evaluating the grade of PCL and NVB degeneration by using clinical, radiological, and perioperative parameters in knee arthritis patients, in theory, could help surgeons in the decision of preserving or not preserving the PCL in a particular patient.

QUESTIONS: (1) Can the degree of the PCL collagen fibers degeneration be predicted by clinical, radiographic, and perioperative parameters in knee arthritis patients? (2) Is the NVB histological degeneration status predictable using clinical, radiographic, and perioperative parameters in the same subset of patients? (3) Is there a correlation between the degree of the PCL collagen fibers degeneration and NVB status in knee arthritis patients?

METHODS: Eighty-nine PCLs (85 patients) obtained from total knee replacement surgery were studied. The histologic degeneration of PCL collagen fibers and the NVB status (preserved, degenerated, not detected) were evaluated. These histological degeneration patterns were correlated with clinical and radiographic parameters and with anterior cruciate ligament (ACL) status.

RESULTS: A small prevalence of preserved NVB was related to Grades IV and V of Ahlbäck's classification, ACL absence, and severe PCL degeneration. The clinical and radiological parameters studied were not able to predict the grade of histological degeneration of the PCL.

CONCLUSIONS: Ahlbäck's classification and ACL status provided useful information about NVB integrity.

LEVEL OF EVIDENCE: Basic Science Level IV.