Marijuana Overuse Associated With Serious Complications After TJA

The numbers here were somewhat eye-opening, and justify asking our patients about it before elective arthroplasty

What’s the Claim?

According to a large-database study of elective noncardiac surgery, cannabis use disorder was associated with an increase in the odds of in-hospital death or serious complications after major elective surgery (odds increase after adjustment: 19% [95% CI 4% to 37%]).

Although this study included a mixed bag of major procedures, 45% of the patient sample had either hip or knee replacement. If you throw spine fusion in there, over 75% of the population studied underwent major orthopaedic procedures, and complication profiles among those operations are pretty similar.

How’s It Stack Up?

The comparator group in this study was very well matched to the study group of patients who had a history of cannabis use disorder in terms of relevant confounding variables, but the endpoints here were limited to inpatient complications and deaths, as this study drew from the Nationwide Inpatient Sample. Fortunately, other studies complement it with longer-term surveillance, perhaps the best recent one being a study using the PearlDiver Mariner database, which tracked patients out to two years and found a 1.6-fold increase in the odds both of 90-day medical complications and two-year implant-related complications. A similiar study offered the same main findings among patients after TKA. It’s worth noting that “cannabis use disorder” is a large group of diagnoses, and it probably doesn’t take much of a weed habit to get coded as having it. This diagnosis hits your chart if a doctor endorses that you have “excessive use of marijuana with associated psychological symptoms and impairment in social or occupational functioning.”

In general, we don’t like composite endpoints like “complications,” since they tend to pool small things (like distal DVT) with big ones (stroke, death). That said, most of the complications in the composite endpoint of the current were serious, so we feel pretty good about the “complications” endpoint the authors created here.

What’s Our Take?