New research from Duke University has dug into the nuances of what knee osteoarthritis (OA) patients want when it comes to surgery. The study, “Patient Preferences for Surgical Treatment of Knee Osteoarthritis,” appears in the December 2, 2020 edition of The Journal of Bone and Joint Surgery.
What Do OA Patients Want and When Do They Want it?

Co-author Chad Mather, M.D., M.B.A., assistant professor and vice chairman of practice innovation in the Department of Orthopaedic Surgery at Duke University School of Medicine, explained to OTW how he and his team decided to organize this particular study: “We have studied methods and approaches for measurement and application of patient preferences in health care over the last five years. Our decision to pursue this work in this field was influenced by our vision for a critical role for personalized shared decision making in the delivery of high value care.”
Surgeon and Patient Voices Needed
“We pursued this particular study because the topic is very relevant and debated currently and we felt that patient preferences for choosing a total or unicompartmental knee replacement (UKA) might be different than surgeon preferences. The reason for this is that surgeons tend to be risk averse particularly with regard to reoperations. Patients should have a voice in this debate and contemporary choice experiment approaches like ours are an ideal vehicle to support that voice.”
The researchers analyzed 258 surveys from 92 males and 164 females, with 72 respondents in the “good-function cohort” and 186 in the “fair/poor-function cohort.”
“Patients placed the greatest value or relative importance on serious complications and rates of revision in both cohorts,” said the authors. “Preference weights did not vary between cohorts for any attribute. In the good-function cohort, 42% of respondents chose TKA and 58% chose UKA. In the fair/poor-function cohort, 54% chose TKA and 46% chose UKA.”
And the key findings and takeaways?
“First, we estimate that approximately half of respondents would choose a UKA. This suggests that the trend of increased utilization of UKA is appropriate and even more so that UKA may be underutilized. The second key finding is that there is a leveling off of the value of increased function at higher levels. In other words, few patients, especially patients who start off at lower functional levels, derive any value from achieving levels of function consistent with participation in activities beyond light exercise.”
Even More Evidence for Shared Decision Making
“The clinical implications of this work are that surgeons should engage in shared decision making with patients regularly and be aware that they may be under-utilizing UKA. We are not necessarily suggesting more should be done, that is a more complex answer, but we are recommending that an unbiased, patient centered shared decision making process should be undertaken.”
“Other implications involve development and measurement. Because little value exist for what we termed super-excellent functional levels, innovations in implant design or other interventions that would facilitate high impact exercise will not generate value for the vast majority of knee arthroplasty patients. With regard to measurement, this finding also suggests that current patient reported outcome instruments are adequate for capturing patient centered outcomes in knee arthroplasty.”

Discussion
This is a fascinating development. In my practice we've seen similar outcomes with the revised protocol. The key differentiator seems to be patient selection criteria. Has anyone else noticed the correlation with BMI thresholds?
Great point. I'd push back slightly on the conclusion, the sample size in the cited study is too small to draw population-level inferences. That said, the directional signal is compelling and worth a larger RCT.
We implemented a similar approach last year. Early results are promising but we're still gathering 12-month follow-up data. Happy to share our protocol if anyone is interested.
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