Study Finds Geographic Variation in Opioid Prescription Rates After Arthroscopic Knee Surgery

“Location, location, location” is a common mantra in real estate, but it may also apply to opioid prescribing practices: A study from the University of Pennsylvania has found that whether arthroscopic knee surgery patients receive a prescription for an opioid largely depends on where they live.

Between 2015 and 2019, 72% of outpatient arthroscopic knee surgery patients in the US who were not already taking an opioid received an opioid prescription after the procedure. But the practice varied widely across the country, from a high of 85% of these patients in Nebraska to a low of 40% in South Dakota.

What was more troubling, though, was the high dosage: The strength of the typical prescription was found to be equal to 50 mg of morphine per day, the level the Centers for Disease Control and Prevention (CDC) has identified as the threshold for increased risk of death from an opioid overdose.

“We found massive levels of variation in the proportion of patients who are prescribed opioids between states, even after adjusting for nuances of the procedure and differences in patient characteristics,” said the study’s senior author, M. Kit Delgado, MD, an assistant professor of Emergency Medicine and Epidemiology in the Perelman School of Medicine at the University of Pennsylvania.

“We’ve also seen that the average number of pills prescribed was extremely high for outpatient procedures of this type, particularly for patients who had not been taking opioids prior to surgery.”

The latter is of increased concern because it contributes to the opioid epidemic. It has been shown that giving a high-dose prescription to patients who have never been on opioids can be associated with a transition to long-term opioid use, higher numbers of leftover pills, and even higher rates of overdose among family members.

The research team chose arthroscopic knee surgery as the lens through which to examine opioid prescription patterns because arthroscopy is among the top 3 most-common outpatient procedures in the US. To gauge prescription rates, the researchers accessed a large national database of insurance claims and identified nearly 100,000 patients who had undergone arthroscopic knee surgery and had not had an opioid prescription in the 6 months before surgery.

The team found that nationwide, 72% of patients filled an opioid prescription within 3 days of their procedure. There was very little variation in the fill-rate between non-invasive procedures, which might include the removal of torn cartilage, and invasive procedures, such as anterior cruciate ligament reconstruction.

Significant differences in prescribing rates were found from state to state. High prescription rates (77% or above) extended across the Midwest into the Rocky Mountain region, from Ohio to Utah, and extended into Arizona and Washington state. Lower rates (below 70%) tended to be on either coast, but also included the Dakotas, Texas, and other states. There was also wide variation in the number of tablets in each single prescription, ranging from 24 in Vermont to 45 in Oklahoma.

“Some factors that may contribute to state variation are policies such as mandates to check prescription drug monitoring program data, which have shown to affect the opioid prescribing rate,” said lead author Benjamin Ukert, MD, a post-doctoral researcher at the University of Pennsylvania at the time of the study and now an assistant professor of Health Policy and Management at Texas A&M.

“However, most state policies are aimed at patients with a history of opioid use, and our study focuses on patients who do not have that history. Thus, practice and organizational styles may be more important factors for this population.”

Although the prescription rate varied greatly, the average prescription translated to roughly 250 mg of morphine over a 5-day period, above the CDC’s threshold for risky opioid prescription. Approximately 25,000 of the patients studied, 36%, were receiving this dosage level or more.

With that in mind, a different study involving Dr. Delgado and another co-author of this study, Brian Sennett, MD, Chief of Sports Medicine at Penn Medicine, is currently being conducted. Using automated text messages to directly check in with patients, it is examining how many opioid tablets they actually take from their prescription after knee surgeries. So far, they’re observing that most patients take fewer than 10 tablets, which jells with what’s been found by other groups.

“These studies suggest that current prescribing patterns are still resulting in a significant number of opioid tablets in the community that could be misused and potentially diverted to others,” Dr. Delgado said. “The data we’ve collected show that there’s ample opportunity to reduce excessive prescribing for this common outpatient procedure.”

Moving forward, more work needs to be done to identify the right prescription to prevent pain but also protect against potential dependence and overdose.

“Given that most arthroscopies are not invasive, there seems to be room to reduce the prescribing rate and the strength of the prescription,” Dr. Ukert said.



Ukert B, Huang Y, Sennett B, Delgada K. State-level variation in opioid prescribing after knee arthroscopy among the opioid-naïve in the USA: 2015–2019. BMJ Open. 2020 Aug 20;10(8):e035126. doi: 10.1136/bmjopen-2019-035126.

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