Cruciate-retaining total knee arthroplasty: How much of the PCL is really retained?

PURPOSE: It is questionable how much of the PCL is really preserved following a complete transverse tibial cut during a cruciate-retaining (CR) total knee arthroplasty (TKA). It is hypothesized that a complete transverse tibial cut jeopardizes the PCL tibial insertion during a common CR TKA. Thus, the aim of the present study was to assess intraoperatively the amount of PCL tibial attachment damage following a standard complete tibial cut technique.
METHODS: Thirty consecutive female patients suffering from degenerative knee osteoarthritis were included. Two measurements were performed on preoperative MRI images. On sagittal plane, the PCL facet of tibia and the PCL tibial attachment were measured. All 30 patients underwent a TKA using a common CR prosthesis. Postoperatively, the amount of PCL facet resection was measured on the resected tibial plateau using a digital sliding caliper.
RESULTS: In preoperative MRI images, the length of the PCL facet of tibia was found 25.5 ± 2.1 mm and the length of the PCL tibial attachment was 14.5 ± 1.3 mm. The amount of PCL facet resection following TKA was 20.6 ± 2.2 mm on average. This result corresponds to an average resection of 65.1 ± 15.9 % of the PCL tibial attachment following TKA.
CONCLUSION: The hypothesis that a complete transverse tibial cut during a conventional CR TKA jeopardizes the PCL tibial insertion was confirmed. According to measurements performed on preoperative knee MRI scans and surgical specimens of resected tibial plateaus, a significant amount of the PCL insertion on the tibia is actually removed in the majority of cases. Surgeons should be aware that when resecting the tibial plateau without using a technique that spares the PCL tibial attachment, there is a high risk of considerable damage to the PCL that may, in turn, increase the likelihood of potential complications due to PCL deficiency. LEVEL OF EVIDENCE: IV.