Thanks a lot. Good afternoon, everybody. I'll talk to you today about the clinical important difference in the past patient acceptable symptomatic state for patients basically with cartilage repair in the knee. I'd like to acknowledge my co-authors, Drew Lansdowne, Annabelle Davey, Eileen Davis, especially Dr. Brian Cole, who completed the study after my fellowship in Chicago. So in terms of current state of patient reported outcome measures, I think what we're all used to seeing is you read a paper, a randomized trial, what you see is a mean or a standard deviation in the context of instruments that are reliable, valid, and responsive. And it's often hard to take that data and interpret it at the level of an individual patient that you're talking to in clinic. And I think there's more and more reasons as time goes on to consider individual patient level data, both in the context of how you design randomized trials, and actually FDA in terms of approving new devices, for example, cartilage restoration devices, has said they require responder analyses. And responder analyses are basically one way in which you look at individual patient data, are patients responders or are they non-responders? And CID in the past is two examples of individual level PROMs that are population specific. So in terms of definitions, the clinical important difference is essentially the amount of change in an outcome instrument that is beneficial as perceived by the patient. And in terms of the past, what it is, it's more of a threshold. It differentiates the state of symptoms, you know, where someone's either well or unwell. And whereas, like, the MCID is really a change score, the past is more of an absolute threshold where you have to exceed it to be considered feeling well based on a patient's perspective. So our objective was really to look at the CID and the past for the COOS, IKDC, the Lysolome score in the knee cartilage restoration population. This is a prospective cohort study from 2012 to 2017. It was patients undergoing isolated and combined cartilage restoration procedures at a tertiary care center in Chicago. The follow-up was one year. We used an anchor-based method to determine CID and past values. The anchor-based method is what's recommended by the FDA. A receiver operator curve analysis was done to calculate values for each relevant patient reporter outcome measure. And we performed a multivariate regression analysis to look at covariates to see how they influence the past and CID estimates as well. So here's what we found. We had 113 patients. The mean age was 36, and 53% were male, 58% of patients. So almost 60% of our sample had prior surgery. And patients were treated with a variety of procedures. As you can see, it's a pretty heterogeneous population. 50 people had an osteochondral allograft, 13 people had ACI, 13 people had a micro fracture. A substantial portion had either chondroplasty or debridement. That might have just been a staging arthroscopy where patients didn't need subsequent surgery. And a few people had a cartilage scaffold, such as knee cart. In terms of concomitant procedures, 13% had a meniscal allograft, and 16% had an osteotomy. Here's the data that we had. If you just look at the COOS values, you'll see that for the various subscales, the clinical important delta you need to achieve is anywhere between 8 to 30. And that's a huge range. So for the subscales like pain and symptoms, you'll notice that you only got to achieve a delta of 8 or 10, and it's pretty easy to achieve that. From a patient's perspective, achieving that delta is important, whereas it's a lot harder to satisfy patients from a quality of life or sports and recreation perspective. The minimal clinical important difference, or the clinical important difference is actually quite large, and so it takes more time and potentially it's harder to achieve it. The PASS values are listed on the right. The IKDC value for CID was 9.2, and for Leishoma it was 13. In terms of prognostic variables, baseline scores did not have an effect on the likelihood of achieving the clinical important difference. However, patients who had a higher baseline score, so you were doing better off pre-op in the upper 50th percentile of the population, you're more likely to achieve the PASS when the patient is at the most symptomatic state, that state of being really good or really well for the IKDC. And there's actually a trend towards that for the COOS sports and recreation subscale. And not surprisingly, we found that patients who were younger, being younger was an independent predictor of doing really well and achieving PASS and CID across all outcome measures. So just as a rule of thumb, if you just take a look at this data, how do the patients in this population do? In terms of meeting the requirements for clinical important difference after complex cartilage restoration procedures in this heterogeneous population, two out of three people on average—well, two out of three people, the rule of thumb is they will improve in terms of pain, symptoms or ADLs. For the IKDC, about two out of three people will achieve that minimal clinical important difference or even a substantial clinical difference. And whether or not they achieve the PASS really depends on where they start. Here's an example. For the COOS pain, the CID is 8.3. The PASS is 72. So if the patient's already above the PASS before surgery, maybe they shouldn't have surgery. If they're below the PASS and the delta is enough, they might get past it. But if they're way below the PASS and even though they achieved the MCID or the CID, it may not be enough. So I think our findings are significant. It's the first study to determine CID and PASS values for PROMs in the cartilage restoration population. This patient population was relatively heterogeneous at baseline and with the treatment approaches employed. Our rule of thumb was that two out of three people improved in terms of CID and PASS values, basically in terms of COOS pain, COOS symptoms, and IKDC. In the future, I think the next step is to look at individual procedures and do procedure-specific determination of CID and PASS estimates. Thanks a lot.

clinical important difference

patient acceptable symptomatic state

cartilage repair

patient reported outcome measures

outcome instrument