# Posterior cruciate ligament tibial attachment sacrifice percentage is higher in cruciate-retaining total knee arthroplasty in patients with discoid lateral meniscus

## TL;DR

This study shows that patients with discoid lateral meniscus lose more of their PCL attachment during a specific knee surgery compared to those without the condition.

## Contribution

The study reveals a higher PCL attachment sacrifice in CR-TKA for patients with discoid lateral meniscus.

## Key findings

- DLM patients had significantly higher PCL resection percentages at all tibial cut slopes compared to non-DLM patients.
- The minimum meniscus width to tibia width ratio weakly correlates with PCL attachment sacrifice.
- CR-TKA in DLM patients may require alternative surgical techniques to preserve PCL attachment.

## Abstract

The posterior cruciate ligament (PCL) attachment may be damaged in cruciate-retaining total knee arthroplasty (CR-TKA) using the complete resection for tibial preparation, and resection amount varies greatly among individuals. Discoid lateral meniscus (DLM) is one of the most common anatomic knee variants. This study aimed to evaluate the difference in PCL attachment sacrifice in CR-TKA between patients with and without DLM.

Fifty-one knees in the study group (DLM group) were matched 1:1 to 51 control knees (non-DLM group) by age, sex, and maximum width of the tibial plateau. The percentage of the sacrificed PCL attachment and the morphological parameters of the tibial plateau were evaluated using magnetic resonance imaging (MRI) in a blind manner.

With a tibial cut simulated at a 0°, 3°, and 7° osteotomy slope, the mean PCL attachment resection percentages in the non-DLM group were 40.5%, 53.6%, and 72.6%, respectively. The corresponding resection percentages in the DLM group were 61.0% (P < 0.001), 73.3% (P < 0.001), and 85.7% (P < 0.001), respectively. The percentage of the minimum meniscus width to the maximum tibia width showed a weak positive correlation with the percentage of PCL attachment sacrifice.

A significantly greater portion of PCL attachment was sacrificed in DLM patients undergoing CR-TKA using the complete proximal tibia resection. Attention should be paid to PCL attachment resection during CR-TKA in patients with DLM, and alternative techniques or prosthesis types should be considered.