FAST OA: PREDICTORS OF POST-TRAUMATIC OSTEOARTHRITIS SYMPTOMS 2 YEARS AFTER ANTERIOR CRUCIATE LIGAMENT RECONSTRUCTION

Abstract

Purpose: While anterior cruciate ligament reconstruction (ACLR) can successfully return athletes to their sports, the injury and subsequent surgery place them at risk of developing post-traumatic osteoarthritis (PTOA). The development of strategies to prevent PTOA has been constrained by the many years it often takes to develop PTOA. After ACLR, most persons have a resolution of symptoms for at least a few years. Testing preventive interventions could occur if a group likely to develop OA quickly could be identified and studied, but it is unknown whether such a group exists. We sought to determine the proportion of patients undergoing ACLR who rapidly develop PTOA symptoms and then created a multivariable model to identify who is at risk of this outcome. This model could be used in future clinical trials of PTOA interventions to selectively enroll patients at higher risk of developing PTOA. Method(s): We used the MOON prospective multicenter cohort of ACLR that enrolled 3273 subjects from the practices of 17 surgeons at 7 sites between 2004 - 2008 and obtained 2-year follow up of 2798 subjects (85%). We set various thresholds of PTOA symptoms including KOOS pain of 80 or worse (KOOS 80), moderate or worse response to at least one question on the KOOS pain scale (KOOS moderate), and meeting the threshold for seeking treatment for knee pain established by the OARSI-OMERACT working group: KOOS knee-related quality of life < = 87.5 AND two or more of KOOS pain < = 86.1, KOOS symptoms < = 85.7, KOOS activities of daily living < = 86.8, or KOOS sports and recreation < =85.0 (OARSI-OMERACT). We calculated the proportion of subjects meeting the threshold for PTOA symptoms at 2-year follow-up by each measure, and then we constructed multivariable logistic regression models using baseline factors to predict the probability of having PTOA symptoms at 2 years. We included demographic factors (age, sex, BMI), surgical factors (presence of meniscal tear or grade 3 or 4 articular cartilage lesion during diagnostic arthroscopy), and baseline KOOS pain score in the model. We calculated model performance using the c-statistic (AUC). Result(s): Baseline characteristics of the cohort are presented in table 1. The mean age was 26.9 years and 45 percent of subjects were female. The proportion of subjects having PTOA symptoms at 2 years was 16.6% for the KOOS 80 threshold, 26.3% for the KOOS moderate threshold, and 44.5% for the OARSI-OMERACT threshold. The significant predictors of having PTOA symptoms in the multivariable logistic regression models included worse baseline KOOS pain, higher baseline BMI, and presence of grade 3 or 4 chondral lesion during diagnostic arthroscopy. (see table 2). Conclusion(s): Depending on the symptom criteria, between 16.6 and 44.5 percent of patients undergoing ACLR have clinically significant symptoms consistent with PTOA at 2 years follow up. Using a clinical prediction model that includes baseline pain, demographic factors, and articular cartilage status could be used to identify patients at higher risk of developing PTOA for entry into a clinical trial. [Formula presented] [Formula presented]Copyright © 2022