By Emily Ledger
Three studies have suggested that using cannabis prior to orthopaedic surgeries can lead to increased complications. The results were presented at the 2021 Annual Meeting of the American Academy of Orthopaedic Surgeons (AAOS), which is being held in San Diego, California.
According to the results, cannabis use before total knee arthroplasty (TKA) and total hip arthroplasty (THA) can lead to increased complications, longer hospital stays, higher rates of adverse events, increased readmissions, and higher costs.
The use of cannabis has been consistently on the rise for decades, making it the most commonly used drug in the world. As more countries and US states continue to legalise both medicinal and recreational cannabis use, there has also been an increase in cannabis use in older populations – who are more likely to require TKA and THA surgeries.
However, the impact of cannabis use on the outcomes of these orthopaedic surgeries remains under-researched.
Impact of cannabis use prior to Total Knee Arthroplasty
In an attempt to address this lack of research, one study aimed to assess the implications of pre-operative cannabis use at 90 days and one year following surgery.
Using a large insurance database, researchers reviewed 3,308 TKA patients between 2010 and 2018 to assess outcomes such as opioid consumption, readmissions, revisions, and complications. The review compared patients who consumed cannabis pre-operatively and those who did not.
The findings showed that dislocation rates were significantly higher among cannabis users than non-users at both 90 days and one year. However, opioid consumption and revision rates did not differ significantly between groups at 90 days.
Associations between cannabis use disorder and perioperative complications
In another study, researchers assessed the relationship between cannabis use disorder (CUD) and outcomes following TKA. The findings showed that CUD patients had significantly longer in-hospital stay lengths compared to other patients.
It was also demonstrated that CUD patients were significantly more likely to develop medical complications within 90 days (28.08% vs. 12.50%), including pneumonia, respiratory complications, myocardial infarctions, and acute kidney injuries.
Cannabis use disorder was also associated with higher rates of prostheses-related complications as well as higher ‘day of surgery’ costs and ‘total global 90-day episode of care’ costs.
Effects of CUD on outcomes following THA
The third study presented at the AAOS was designed to determine whether CUD patients undergoing primary THA experienced higher rates of in-hospital lengths of stay (LOS), complications, and cost of care.
The study found that CUD patients undergoing primary THA had significantly longer in-hospital LOS (4 days vs. 3 days) compared to patients without CUD.
This subgroup also experienced a higher frequency of adverse events (11.23% vs. 4.82%), including higher rates of pneumonia, respiratory failure, cerebrovascular accidents, urinary tract infections, and acute renal failure. CUD patients also had significantly higher total global 90-day costs of care.
While there is still little research in this area, the results of these studies suggest a negative relationship between cannabis use prior to orthopaedic surgeries – particularly in patients with cannabis use disorder. These studies support the need for further research in order to help orthopaedic surgeons educate and offer guidance to patients prior to surgery.