Is the posterior cruciate ligament destabilized after the tibial cut in a cruciate retaining total knee replacement? An anatomical study

Cruciate retaining total knee replacement has been shown to effectively improve pain and quality of life. Successful outcomes depend on many factors, including the maintenance of a competent posterior cruciate ligament. This study sought to anatomically analyze the percentage of PCL injured during a full transverse, tibial cut, thus altering normal function.

One hundred and thirty five consecutive knee MRIs taken from 2006 to 2011 were selected from a single surgeon’s database for this study. Only subjects with non-arthritic knees were considered for this study; the lack of degenerative joint disease (DJD) was confirmed via a radiological report. The optimal view of the PCL’s tibial attachment was observed using the sagittal view of the knee, with a T1 signal. One hundred and twenty two usable images were viewed electronically, and measurements were made using the standardized transverse cut implant guidelines. The percentage of PCL remaining following the cut was categorized into five different groups: 0% (no PCL undermined), 1–49%, 50–74%, 75–99% and 100% (PCL undermined entirely).

Overall only 9.0% ( n = 11) would have not endured any damage to the PCL with a transverse tibial saw cut, while 79.6% ( n = 98) would have had 50% or more of the PCL undermined. Of the 98 patients with more than 50% resected, 52.1% ( n = 51 patients) presented complete destabilization of the PCL. The percentage of PCL destabilized was not significant across age groups ( p = 0.280), gender ( p = 0.586), or operative side ( p = 0.460).

Independent of age, gender, and operative side, a majority of PCLs are more than 50% destabilized following the standard transverse tibial cut.

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