Relationship Between Quantitative MRI UTE T2* of ACL Autografts and BMI-Normalized Knee Laxity Within the First Year After ACL Reconstruction

Authors

• Alonso Figueroa
• Tomasz Bugajski
• Dillon Humpal
• Manickam Kumaravel
• Walter Lowe
• Payam Zandiyeh

Language

English

Publication Date

10-1-2025

Journal

The American Journal of Sports Medicine

DOI

10.1177/03635465251368393

PMID

40970673

PMCID

PMC12489169

PubMedCentral® Posted Date

9-19-2025

PubMedCentral® Full Text Version

Post-print

Abstract

Background: The anterior cruciate ligament reconstruction (ACLR) graft undergoes a remodeling process that affects its structural properties. Ultrashort echo time T2* (UTE-T2*) imaging has been instrumental in examining this process. However, more research is needed on the postoperative relationship between UTE-T2* of the graft and its mechanical properties.

Purpose: To longitudinally examine ACL graft changes after ACLR using UTE-T2* decay coefficients and knee laxity and explore their relationship.

Study design: Case series; Level of evidence, 4.

Methods: A total of 31 patients who underwent ACLR had magnetic resonance imaging of their knees at 1, 6, and 12 months after surgery using a UTE-T2* sequence. Bilateral knee laxity was measured at 6 and 12 months using a GNRB arthrometer (force = 200 N). UTE-T2* coefficients of the graft were calculated using mono- (T2m*) and biexponential (short [T2s*] and long [T2l*]) analyses, and outcomes were normalized to body mass index. Linear mixed models were used to determine longitudinal changes in UTE-T2* and laxity; the Pearson correlation was used to explore the correlations between these outcomes.

Results: T2m* of the graft increased from 1 to 6 months (Δ = 0.092; P = .008), followed by a decrease from 6 to 12 months (Δ = -0.079; P = .021). Regardless of the limb side, a decrease in laxity was detected between 6 and 12 months after surgery (Δ = -0.033; P = .046). Positive correlations between laxity and UTE-T2* were detected at 6 months (T2s*: R = 0.285; P = .025) and 12 months (T2m*: R = 0.532; P < .01; T2s*: R = 0.669; P < .001; T2l*: R = 0.354; P = .034).

Conclusion: Biexponential analysis of UTE-T2* MRI provides a sensitive tool for detecting structural changes in the graft after ACL reconstruction, reflecting the dynamic process of graft remodeling. Among the decay coefficients assessed, T2s* demonstrates a stronger correlation with postoperative laxity, highlighting its potential as a critical biomarker for monitoring graft integrity over time.

Keywords

Humans, Anterior Cruciate Ligament Reconstruction, Magnetic Resonance Imaging, Male, Female, Joint Instability, Adult, Young Adult, Body Mass Index, Knee Joint, Anterior Cruciate Ligament Injuries, Adolescent, Longitudinal Studies, Autografts, Anterior Cruciate Ligament, Transplantation, Autologous, anterior cruciate ligament, anterior cruciate ligament reconstruction surgery, autograft, biexponential decay, graft remodeling, knee, knee laxity, ligamentization, magnetic resonance imaging, monoexponential decay, ultrashort echo time T2*

Published Open-Access

yes

Recommended Citation

Figueroa, Alonso; Bugajski, Tomasz; Humpal, Dillon; et al., "Relationship Between Quantitative MRI UTE T2* of ACL Autografts and BMI-Normalized Knee Laxity Within the First Year After ACL Reconstruction" (2025). Faculty, Staff and Student Publications. 4019.
https://digitalcommons.library.tmc.edu/uthmed_docs/4019