No Clinically Relevant Change Between 1 and 2 Year Outcomes Following ACL Reconstruction
Authors: Nguyen Joseph , Rodeo Scott A. 
Published: July 2017

Objectives: Anterior cruciate ligament (ACL) injury has an annual incidence of more than 200,000 cases with almost 100,000 undergoing ACL reconstruction (ACLR). Many institutions have built ACL registries to better understand treatment outcomes and raise overall standards of care. One limitation of these registries is the continued compliance of patients to fill out post-operative patient-reported outcome surveys over time, with most beginning data collection 2 years after surgery. With most ACLR patients returning to activities or sport between 1 and 2 years after surgery, and registry attrition rates increasing with every year removed from surgery, it would be beneficial to focus follow-up data collection beginning 1-year post-operatively. The purpose of this study was to evaluate if a clinically meaningful change exists from 1 to 2-year follow-up in patient-reported outcome measures for patients undergoing ACL reconstruction. Methods: Patients who underwent primary ACLR from 2010 and 2012 in our institution’s ACL registry were included. IKDC Subjective and Marx Activity surveys were collected pre-operatively and at 1 and 2-year follow-ups. Two-way repeated measures ANOVA was used to evaluate changes in IKDC and Marx scores. Differences between ages, sex, graft type, and meniscal and cartilage pathology were assessed. Bonferroni-adjusted post hoc tests were used to assess pairwise comparisons of each time point. Chi-square tests were used to compare the proportion of patients who attained minimally clinically important difference (MCID) from 1 to 2 years. Results: 1,037 enrolled patients underwent ACL reconstruction from 2010 to 2012 - 893 being primary procedures. IKDC or Marx surveys were available in 289 patients. Overall, IKDC scores significantly improved from baseline to 1 year (32.9 points, p<0.001). Overall change in IKDC was statistically significant from 1 to 2 years; however, mean change was 3.2 points, well below published MCIDs. Only 12% of patients attained clinically relevant change from 1 to 2 years. Range of IKDC scores between various factors was 0.5 to 5.6 points. There was no difference in percentage of those who reach the MCID between factors. Change in Marx scores was significant from baseline to 1 year (-2.2, p<0.001), but not significant from 1 to 2 years (0.1, p>0.999). Mean change was not significant between groups, with mean scores ranging from -0.6 to 1.0 from 1 to 2 years. Conclusion: Significant and meaningful changes were found in IKDC and Marx scores from baseline to 1-year follow-up. However, no clinically meaningful difference was found in both IKDC and Marx scores from 1 to 2 years follow-up. To our knowledge, this is the first study to look at longitudinal evaluation of patient-reported outcomes at these given time points with a high volume of patients. Future studies should look at why there is no significant change between 1 and 2 year outcomes, but given the lack of a clinically relevant change from 1 to 2 years and the challenges and resources required for patient follow-up, ACL-related studies should consider collecting 1 year outcome surveys to maximize follow-up retention in their patient cohort along with complementing this data with additional relevant outcome assessments such as radiographic evaluation and functional tests that measure readiness to return to play. [Table: see text]