# Injury of the posterolateral corner of the knee does not lead to higher intra‐articular external tibial rotation in the MRI

## TL;DR

This study found that injuries to the posterolateral corner of the knee do not increase tibial rotation visible on MRI scans.

## Contribution

The study demonstrates that MRI does not show increased tibial rotation in PLC injuries, challenging prior assumptions.

## Key findings

- No significant difference in SEA-PTC or PFC-PTC angles between PLC-injured and control groups.
- The dial test remains a reliable clinical tool for assessing PLC injuries.
- SEA-PTC and PFC-PTC measurements were strongly correlated in both groups.

## Abstract

The aim of this study was to evaluate external tibial rotation using magnetic resonance imaging (MRI) in patients with injuries to the posterolateral corner (PLC) of the knee.

A retrospective analysis of 26 patients with PLC injury (study group) was performed and compared with a control group of 100 patients without knee injuries. Intra‐articular tibial rotation was assessed in MRI measuring two angles: (1) between the surgical epicondylar axis (SEA) of the femur and the posterior tibial condyle line (PTC) (SEA‐PTC); and (2) between the posterior femoral condyle (PFC) and the PTC (PFC‐PTC). Results were aligned with the dial test (DT), representing the clinical assessment of PLC injuries. The statistical significance of differences in SEA‐PTC and PFC‐PTC was evaluated using a two‐sided Welch's t test.

The mean SEA‐PTC was −6.3 ± 7.9° (study group) versus −6.1° ± 4.0° (control group), and the mean PFC‐PTC was −5.2 ± 2.4° (study group) versus −5.4 ± 1.5° (control group). There were no statistical differences regarding the SEA‐PTC or the PFC‐PTC between both groups (p = 0.87 and p = 0.87, respectively). DT was positive in 80% of patients with PLC injury; thus, sensitivity was 80%. SEA‐PTC and PFC‐PTC were not statistically different between DT positive/negative patients (p = 0.89 and p = 0.1, respectively). There was a significant correlation between SEA‐PTC and PFC‐PTC (R = 0.88; p < 0.001).

PLC injuries are not associated with increased external tibial rotation in the MRI, while the DT is a valuable method for the clinical assessment of PLC injuries.

Level III.