Association of Preoperative Cartilage T1ρ Values With Progression of Knee Osteoarthritis 10 Years After Anatomical Double-Bundle ACL Reconstruction: Follow-up of a Previous Prospective Study.

Abstract

Background: The factors contributing to osteoarthritis progression after anterior cruciate ligament (ACL) injury and reconstruction (ACLR) are not fully understood. Quantitative magnetic resonance imaging (MRI) offers a noninvasive way to evaluate cartilage biochemical composition using T1ρ mapping, thereby detecting early cartilage degeneration. The specific impact of preoperative quantitative MRI on long-term outcomes after ACLR remains underreported.

Purpose/hypothesis: The purpose of this study was to investigate the effects of various factors, including preoperative cartilage T1ρ values, on the 10-year outcomes after ACLR. It was hypothesized that individual differences in baseline cartilage degeneration would influence osteoarthritis progression at 10 years postoperatively.

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

Methods: This case series involved 13 patients with primary ACL injury who underwent anatomical double-bundle ACLR using hamstring tendon autograft between April 2012 and August 2013. All patients underwent preoperative quantitative MRI using a 3.0-T scanner with an 8-channel knee coil. Cartilage was divided into 18 compartments for compositional analysis, and average T1ρ values were calculated for each compartment. At the 10-year follow-up, 9 of the patients were available for patient-reported outcome (PRO) measures and radiographs.

Results: The 9 patients (6 female, 3 male) had a mean age of 26.4 years and a mean body mass index of 23.3 at surgery. All patients exhibited favorable PRO scores at the 10-year follow-up, but 5 patients showed osteoarthritis progression according to Kellgren-Lawrence (KL) grade. Although preoperative T1ρ values did not significantly correlate with PRO scores, patients with KL grade progression had significantly higher preoperative T1ρ values in the posterolateral tibial cartilage than those without progression (P = .04).

Conclusion: Ten years after anatomical double-bundle ACLR, most patients reported favorable outcomes. Preoperative T1ρ values were not directly correlated with PROs, although the presence of a patient subset with progressive KL grades suggests that preoperative posterolateral tibial cartilage condition may influence long-term osteoarthritis progression.