Early Knee Osteoarthritis Changes Pre- And Post-Anterior Cruciate Ligament Reconstruction Assessed By the Semi-Quantitative MRI Osteoarthritis Knee Score (MOAKS) Case Series and Case-Control Study
Abstract Background: Semi-quantitative scoring of knee abnormalities on magnetic resonance imaging (MRI) can aid in the diagnosis of early stage knee osteoarthritis (OA). Injuries to the anterior cruciate ligament (ACL) and medial meniscus (MM) can contribute to the development of knee OA, but their relationship to its time of onset is unknown.Purpose: To analyze the factors contributing to early knee OA changes in ACL injured knees using MRI Osteoarthritis Knee Score (MOAKS). Methods: Thirty-four cases status post unilateral ACL reconstruction (ACLR) were included. Knee OA abnormalities were evaluated using MOAKS scores of MRIs performed pre- and post-ACLR. Using multiple linear regression analysis, the MOAKS scores of medial osteophytes, medial cartilage alteration, and patellofemoral cartilage alteration were determined as dependent variables. Age, the presence of a meniscal abnormality, the time from injury to ACLR, and body mass index (BMI) were determined as explanatory variables. MOAKS differences between knees with and without medial meniscus (MM) abnormality were tested for each variable using a 2-way repeated-measures analysis of variance with the factors of preoperative vs. postoperative status and MM abnormality. Results: In the pre-ACLR multiple linear regression analysis, the waiting period was significantly and positively associated with medial cartilage loss, Lateral femorotibial osteophytes, lateral cartilage loss. and BMI were positively associated with MM abnormalities. BMI and lateral meniscus (LM) abnormality were significantly associated with lateral cartilage loss. Age was significantly associated with medial osteophytes. Age and LM abnormality were significantly associated with lateral osteophytes. Age, BMI, and LM abnormality were significantly associated with patellofemoral osteophytes. Conclusion: We found early knee OA changes in most knees a mean of 28.2 ± 52.0 months after ACL injury. The time from injury to ACLR, BMI, and the presence of MM or LM abnormality in the ACL injured knee were associated with early knee OA changes. In the ACL injured knee with MM involvement, prompt ACLR may forestall the development of OA.