# Temporal changes in tibiofemoral relationship following anterior cruciate ligament injury: Implications for rotational dynamics and clinical outcomes

## TL;DR

This study examines how the tibiofemoral joint changes after ACL injury and finds that the tibia rotates internally over time, which may affect clinical outcomes.

## Contribution

The study highlights the importance of rotational changes in ACL-injured knees and their potential impact on patient outcomes.

## Key findings

- The tibia translates anteriorly and rotates internally relative to the femur after ACL injury.
- ΔTT-TG distance negatively correlates with time since injury (r = -0.44, p < 0.01).
- No correlation was found between ΔMedial ATT, ΔLateral ATT, or ΔTT-TG distance and patient-reported outcome scores.

## Abstract

This study aims to elucidate changes in the tibiofemoral relationship over time following anterior cruciate ligament (ACL) injury, and investigate the correlation between the tibiofemoral relationship and patient‐related outcome measures (PROMs).

Overall, 203 primary ACL reconstructions were performed using autologous hamstring grafts. Medial and lateral anterior tibial translation (ATT) in the sagittal plane and tibial tubercle‐trochlear groove (TT‐TG) distance in the axial plane were measured using pre‐operative magnetic resonance imaging and post‐operative computed tomography. The difference between pre‐operative and post‐operative values for each parameter was calculated: ΔMesdial ATT, ΔLateral ATT and ΔTT‐TG distance. The correlation between each calculated value and the time elapsed since ACL injury, and the correlation between each calculated value and PROMs—evaluated using the Knee Injury and Osteoarthritis Outcome Score (KOOS)—were assessed.

Sixty‐four patients were enroled. Medial ATT, lateral ATT and TT‐TG distance were significantly different pre‐operatively compared to post‐operative values, with the tibia translating anteriorly and rotating internally relative to the femur. ΔMedial ATT, ΔLateral ATT and ΔTT‐TG distance were 1.6, 8.8 and −4.8 mm, respectively. A negative correlation was observed between the ΔTT‐TG distance and the time elapsed since the injury (r = −0.44, p < 0.01). No correlation was found between ΔMedial ATT and the time elapsed since the injury, nor between ΔLateral ATT and the time elapsed since the injury. Neither the ΔMedial ATT, ΔLateral ATT, nor ΔTT‐TG distance correlated with the pre‐operative or post‐operative KOOS subscale scores.

The tibia underwent internal rotation relative to the femur over time following ACL injury, highlighting the importance of assessing rotational changes in ACL‐injured knees.

Level Ⅲ.