What Is a “High-Priority” Knee Replacement?

This post comes from Fred Nelson, MD, an orthopaedic surgeon in the Department of Orthopedics at Henry Ford Hospital and a clinical associate professor at Wayne State Medical School. Some of Dr. Nelson’s tips go out weekly to more than 3,000 members of the Orthopaedic Research Society (ORS), and all are distributed to more than 30 orthopaedic residency programs. Those not sent to the ORS are periodically reposted in OrthoBuzz with the permission of Dr. Nelson.

The coronavirus epidemic has caused all of us to “rethink” many things. Several days ago, a radiologist asked me whether 3 of my requested imaging studies were high priority in light of the pandemic. My response was, “God bless you. No, none of those is urgent.”

I am 79 years old and think back to my first year of orthopaedic residency, 1968. In 2020, the expectation among many patients is for immediate relief, and many orthopaedists try to deliver that. Whatever “new normal” emerges after the COVID-19 surge subsides, how will patients and physicians work together to arrive at a decision when to proceed to a knee replacement? Although knee replacement can result in pain and function salvation for patients with end-stage knee osteoarthritis, as many as 20% of patients report “unsatisfactory” results.

A recent “appropriateness” analysis of data from 2 multicenter cohort studies classified 3,417 potential knee replacements as follows:

• Timely—total knee replacement took place within 2 years after the procedure had met “potentially appropriate” criteria
• Potentially Appropriate but Not Replaced (for >2 years after the procedure had met appropriateness criteria)
• Premature—a replacement that the authors deemed inappropriate but was performed anyway.

The authors found that surgery for 9% of the knees for which replacement was potentially appropriate took place in a “timely” manner. But overall, there was a high prevalence of both delayed and premature surgery. Specifically, 91% of the knees for which replacement was potentially appropriate were not replaced, and 26% of the 1,114 total knee replacements that were performed were considered to be “likely inappropriate” and therefore “premature.”

The likelihood of a knee being classified as potentially appropriate but not undergoing replacement was greater among black patients, and the likelihood of having premature total knee replacement was lower among participants with a body mass index of >25 kg/m² and those with depression.

In a Commentary on this study, Michael G. Zywiel, MD noted that the Escobar appropriateness criteria used in the analysis focuses predominantly on physician-assessed rather than patient-assessed factors. This all begs the question: Now that we have joint-replacement tools that we could not even dream of in 1968, how do we as responsible surgeons help guide our patients in deciding when the time is right to use them?