Good afternoon. I want to thank AOSSM for giving me the opportunity to speak about our work developing and validating the QOOS ACL today. And I have no disclosures to report. This project was born out of known limitations with using the QOOS to investigate outcomes in ACL patient populations, and specifically that there was no evidence to support the structural validity of the QOOS when assessing ACL patients. Structural validity refers to the degree to which the scores of a patient-reported outcome adequately reflect the different dimensions of the construct being measured. So essentially this gives us important information about the appropriateness and interpretability of subscale scores. This small image at the top is the intended five-factor structure of the QOOS. However, when we investigated the structural validity of this structure in the baseline stability one sample of over 600 young active patients with ACL tears, we found that this structure was not confirmed and many changes were needed to obtain an adequate fit in the structure. And that results in the structure that you see here, which would not be appropriate for use because of the significant overlap between the different subscales. So this decreases our confidence in interpreting the five QOOS subscales as they're labeled. Therefore we determined that the QOOS did not have adequate structural validity to assess young active patients with ACL tears, and we sought to create a short-form version that would be structurally valid and relevant to our population of interest. Through exploratory and confirmatory factor analyses, we developed the QOOS ACL, which is a 12-item questionnaire. Eight items make up a function score, and four items make up a sport score. To validate this measure, we started with preliminary validation in our stability one data set, expanding to the four follow-up time points. So we had 618 young active patients with ACL tears who had a hamstring tendon autograft, with or without a lateral extra-articular tenodesis, assessed at baseline, 3, 6, 12, and 24 months post-operative. And it was really important to us to make sure we did an external validation of this measure, and we were fortunate enough to be able to use the Moon Group Young Athlete Cohort of over 800 young patients, high school and collegiate age athletes, who had a hamstring or patellar tendon autograft. And these patients were followed up at baseline, 2, 6, and 10 years post-operative. So this is the final structure of our QOOS ACL, and in preliminary validation, this structure was confirmed, and psychometric properties, which I'll touch on in the next slide, were validated at all five study time points. Looking more closely at our external validation, we assessed the same psychometric properties as we had preliminarily, which included structural validity, convergent validity, internal consistency, reliability, and responsiveness of the QOOS ACL. All of these properties were deemed acceptable at all four time points in the Moon Group cohort, and importantly, that structure that you saw on the previous slide held true with adequate fit at each time point. This graph shows the mean QOOS ACL function and sports scores at each follow-up time point in the Moon cohort. And here we've combined our StabilityOne dataset in purple from baseline to 24 months post-operative with the Moon Group data in yellow at baseline, 2, 6, and 10 years post-op, just to show an imagined continuum of QOOS ACL scores from baseline all the way up to 10 years post-op. So based on these analyses, we believe that the QOOS ACL should be used in place of the full-length QOOS to assess young, active patients with ACL tears. Because of its adequate structural validity, we validated this structure at time points from baseline to 10 years post-op, and this can increase our confidence in interpreting the sport and function score as they're labeled, which is an improvement above the full-length QOOS, which did not have adequate structural validity in this specific patient population. We have determined adequate psychometric properties that are equivalent to that of the full-length QOOS in both our preliminary and external validation of over 1,400 patients. And obviously the decreased length from 42 down to 12 items will decrease patient burden and may reduce the number of patients lost to follow-up, which can be especially important for this younger patient population. Because we haven't changed any of the original QOOS items that remain in the short-form QOOS ACL, you can extract short-form scores from the full-length QOOS to look at data sets retrospectively, or clinicians and researchers can choose which version they feel is more appropriate at different time points. So we validated the QOOS ACL from baseline to 10 years post-op, but it may be more appropriate to use the full-length version after 10 years when some of those items more related to osteoarthritis-type symptoms and impairments might be more relevant. Lastly and most importantly, we've optimized this outcome measure to our population of interest, the high-functioning, young, active ACL patient, and all our development and validation analyses have been done in samples of these patients. So we brought the QOOS from a knee-specific to the QOOS ACL, which is now our ACL-specific measure. I want to thank everyone that's helped support this work, especially my supervisors, Dr. Getgood and Dr. Bryant at Western University, the Stability Group, and Dr. Spindler and the Moon Group. Thank you.

QOOS ACL

questionnaire

ACL tears

structural validity

psychometric properties