Extended-release opioids after joint replacement: small, consistent harms

Design

Population-based comparative effectiveness study, propensity overlap weighting

Population

258,624 adults after elective hip or knee arthroplasty, Ontario

Primary outcome

Persistent postoperative opioid use

Effect

6.0% vs 5.2%; aOR 1.08 (1.01-1.15)

This population-based study used linked Ontario records for 258,624 adults having elective primary hip or knee replacement between 2013 and 2022. It compared those who filled a new extended-release opioid prescription within seven days of discharge (12.1%) with those who did not, using propensity overlap weighting.

Persistent postoperative opioid use developed in 6.0% of those given extended-release opioids and 5.2% of the rest (aOR 1.08, 95% CI 1.01 to 1.15). Readmission within 90 days (aOR 1.09) and emergency visits (aOR 1.16) were also more likely. Costs over a year were lower in the extended-release group, and days alive at home marginally higher.

The differences are small and observational, and the cost finding is hard to explain, which suggests residual confounding. But the direction of clinical harm is consistent across outcomes, and guidance already discourages extended-release opioids for acute pain. In Indian practice, where tramadol and tapentadol extended-release forms are widely prescribed at discharge, this is a reason to prefer short courses of immediate-release drugs alongside regular non-opioid analgesia.

• Avoid new extended-release opioids for acute pain after joint replacement.
• Prescribe a short, defined course of immediate-release opioid only if needed, with a stop date.
• Build discharge analgesia on regular paracetamol and an NSAID where safe.
• Tell the patient and their GP when the opioid should stop, and who to contact if pain persists.

Why it matters

Discharge prescriptions set the pattern for persistent opioid use, and the extended-release choice adds a small but avoidable risk.

Don't overread it

Observational data with small effect sizes; unmeasured differences between patients may explain part of the gap.

The statistics, in plain English

An odds ratio of 1.08 means about 8% higher odds of persistent use; with a baseline near 5%, that is under one extra case per hundred patients. Small effects reach significance in very large datasets, so the clinical weight comes from consistency across outcomes, not size.

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