Marijuana-dependent patients may face higher infection rates after knee and shoulder arthroscopy

Marijuana-dependent patients may face higher infection rates after knee and shoulder arthroscopy

Patients dependent on marijuana may face higher infection rates after knee and shoulder arthroscopy — a minimally invasive surgery that uses a small camera to diagnose and sometimes treat injuries — according to a study presented at the American College's Scientific Forum Clinical Congress of Surgeons (ACS) 2022.

Using PearlDiver, a national insurance claims database, researchers at the University of Chicago conducted a retrospective study of patients with marijuana addiction who underwent knee or shoulder arthroscopy for postoperative complications such as deep vein thrombosis (DVT), pulmonary embolism (PE), and infections.

"Marijuana is so popular, but it's a risk factor that we don't really recognize," said lead study author Sarah Bhattacharjee, MD, who conducted the research while in medical school at the University of Chicago. Dr. Bhattacharjee is now a resident in orthopedics and sports medicine at the University of Washington. “The higher infection rate found in this new study should be a warning sign to patients and providers and should be discussed along with other risk factors prior to arthroscopic surgery.”

Although the effects of marijuana use on pain management and cardiovascular health have been studied, few studies have addressed the potential effects of marijuana use in patients undergoing surgery. More states are legalizing marijuana and the size of the cannabis market is expected to reach $91.5 billion by 2028. Given this trend, the University of Chicago research team set out to find out whether marijuana addicts are at increased risk of complications after knee or shoulder arthroscopy.

There is so much information about smoking, alcohol and other substances, but not about marijuana use. As providers and surgeons, we should be talking to our patients about marijuana use, something we have traditionally shied away from.”

Jason Strelzow, MD, study co-author, assistant professor of orthopedic surgery, University of Chicago

Study details

All patients who underwent knee or shoulder arthroscopy were retrospectively identified in PearlDiver. Next, patients who had a diagnostic code for marijuana dependence were also identified within each surgical category; This is a rigid definition that requires patients to meet three or more criteria, such as using marijuana for longer than intended, having difficulty limiting use, spending a lot of time getting or recovering from marijuana, and high tolerance.

Rates of DVT, PE, and infection within 90 days were determined for all patients. Univariate analyzes of marijuana dependence were performed for all outcomes, followed by multivariate logistic regression analysis controlling for known patient comorbidities (other medical conditions).

Key findings

• Researchers identified 1,113,944 knee and 747,938 shoulder arthroscopy patients. Of these 1,861,892 patients, 21,823 patients had a diagnosis code for marijuana dependence.

• In both subgroups, the marijuana dependence cohort experienced increased rates of infection and DVT, while the PE rate remained the same. In the shoulder arthroscopy group, infection rates increased from 0.7% to 1.7%, DVT rates increased from 0.2% to 0.4%, while PE remained at 0.2%. In the knee arthroscopy group, infection rates increased from 1.1% to 2.6%, DVT rates increased from 0.2 to 0.3%, and PE remained at 0.3%.

• In the multivariate analyses, which took into account a variety of patient risk factors, including tobacco use or a history of diabetes, marijuana dependence was identified as an independent risk factor for infections in both cohorts. In this study, a statistical measure called a p-value (“p” stands for probability) was used to determine whether the detected relationship was due to chance (p-values ​​of 0.001 or less) or actually existed (S-values ​​above 0.001). The p-value was 1.85 for the knee group and 1.65 for the shoulder group.

(Note: The presenting author reported updated data from the panel during the conference reflecting stable PE rates.)

Dr. Streltsow hopes surgeons will use the study results to educate marijuana-dependent patients about risks, benefits and available alternatives, such as reducing or eliminating marijuana use six months before arthroscopic surgery.

Although the study focused on minimally invasive surgery, Dr. Streltsow said that “we would expect similar or greater effects with more open or invasive procedures.”

Future research opportunities

The study identified the need for additional research to better understand the connection between marijuana addiction and postoperative complications. Additionally, because the study used very strict criteria for marijuana dependence, there are opportunities for future clinical trials to examine how different levels of marijuana consumption affect postoperative complications. Dr. Streltsov said he plans to study the effects of marijuana addiction on fracture healing.

Source:

American College of Surgeons

.