Reply to the Letter to the Editor: Preoperative Pain and Function Profiles Reflect Consistent TKA Patient Selection Among US Surgeons

To the editor,

We read the letter from Riddle and colleagues regarding our recently published paper [1] with great interest.

We agree that enhanced preoperative appropriateness criteria is necessary to assure ideal individual patient selection and timing for primary total knee replacement. However, defining individual patient appropriateness was not the purpose of our paper. The major goals of our paper are below.

First, we performed our analyses at the practice level (not patient level). We did this for important methodological and clinical reasons. Methodologically, patient-reported outcomes are validated for use at the aggregate practice or population level. Therefore, we analyzed the measures at the practice level. We made no effort to determine “appropriateness” at the individual patient level. Second, our stated goal was to assess the consistency of practice-level total knee replacement patient selection. To address this question, we reported median, 25^th, and 75^th percentiles of the preoperative pain and function patient profiles across 22 sites in the early Function and Outcomes Research for Comparative Effectiveness in Total Joint Replacement (FORCE-TJR) data. A more recent analysis with 140 surgeons and more than 8000 primary total knee replacement procedures has been submitted for publication, and would validate our observation that the median, 25^th, and 75^th percentile are consistent across practices. These data support that diverse surgeons use similar pain and function criteria to select patients for total knee replacement, in aggregate. We agree that minimum clinically important changes are traditionally applied at the individual patient level. We reported the minimum clinically important changes for context when interpreting the small differences in median pain and function we observed at the practice level. Finally, measures of central tendency, both median and mean, are useful for characterizing aggregate profiles and are not intended to define outliers. We acknowledge that these measures do not reflect both the patients with greater (or lesser) pain or functional limitations.

In the future, FORCE-TJR will test clinically-refined guidelines to support individual patient decisions for total knee replacement. We hypothesize that merging clinician assessments with patient-reported symptoms can guide total knee replacement timing and use decisions. However, until the data include refined clinical assessments, we propose that “appropriateness” labels cannot be assigned to individual patient decisions.