Meta-analysis found cannabis use disorder linked to more complications and higher costs after hip and knee replacements | Research

The takeaway

A meta-analysis of nearly 18 million joint replacement patients found cannabis use disorder was associated with 33% higher medical complications, 75% higher implant complications, and greater financial burden.

Orthopedic surgeons performing joint replacements; anesthesiologists and perioperative teams managing cannabis-using patients.

18 million patients; 75% higher implant complications with CUD

What the researchers found

Across 10 studies with 17,981,628 participants, CUD was associated with significantly higher odds of medical complications (OR 1.33), implant-related complications (OR 1.75), cardiac complications (OR 1.95), stroke (OR 2.06), infections (OR 1.68), periprosthetic fracture (OR 1.42), mechanical loosening (OR 1.54), and dislocation (OR 1.88). Longer hospital stays and higher costs were also found.

Why it matters

Joint replacement is one of the most common elective surgeries. With cannabis use disorder increasing alongside legalization, this meta-analysis quantifies the specific complications orthopedic surgeons should watch for and discuss with patients.

The numbers in context

17,981,628 total participants across 10 studies. Cardiac complications OR 1.95. Stroke OR 2.06. Infections OR 1.68. Periprosthetic fracture OR 1.42. Mechanical loosening OR 1.54. Dislocation OR 1.88. All statistically significant.

How the study worked

Systematic review and meta-analysis searching PubMed, Embase, Scopus, and Web of Science up to July 2018. 10 retrospective cohort studies included. Random effects model used for pooled odds ratios.

What this study cannot tell us

All included studies were retrospective cohorts. CUD diagnoses likely represent more severe cannabis use, not casual use. Cannot separate CUD effects from polysubstance use or socioeconomic factors. Search limited to July 2018.

How to read the evidence

Meta-analysis of 10 studies with very large sample, though all component studies were retrospective cohorts.

When this study was published

2024 study

The bigger picture

The consistency of increased risk across multiple complication types suggests cannabis use disorder may have systemic effects on surgical recovery, immune function, and bone-implant integration that go beyond the known cardiovascular effects of cannabis.

Questions still open

What biological mechanisms link cannabis to implant loosening and periprosthetic fracture? Does cannabis affect bone healing or immune response around implants?

Common questions

Does casual cannabis use carry the same risks?

This study focused on cannabis use disorder, which represents a clinical diagnosis of problematic use. Whether casual or infrequent cannabis use carries similar surgical risks is not addressed.

Why might cannabis affect implant outcomes?

The study does not identify specific mechanisms, but cannabis has known effects on inflammation, blood flow, and bone metabolism that could theoretically affect how well implants integrate and heal.

Read the original research

Cannabis Use Disorder Associated With Increased Risk of Postoperative Complications After Hip or Knee Arthroplasties: A Meta-analysis of Observational Studies.

The Journal of the American Academy of Orthopaedic Surgeons, 32(20), e1067-e1078

View on PubMed ↗Publisher’s paper ↗

Citation

Ding, Cheng; Xu, Dongdong; Cheng, Tao. (2024). Cannabis Use Disorder Associated With Increased Risk of Postoperative Complications After Hip or Knee Arthroplasties: A Meta-analysis of Observational Studies.. The Journal of the American Academy of Orthopaedic Surgeons, 32(20), e1067-e1078. https://doi.org/10.5435/JAAOS-D-23-00407