A population-based cross-sectional analysis of extended-release opioid dispensing incidence, prognostic factors, and variation after total joint arthroplasty

INTRODUCTION: Extended-release opioids (EROs) are not recommended for acute postoperative pain, yet their prescribing persists. This study examined the incidence, predictors, and variation in ERO dispensing after total hip and knee arthroplasty. METHODS: We conducted a population-based cross-sectional study of adults undergoing primary total hip or knee arthroplasty between 2013 and 2022 using linked administrative databases in Ontario, Canada. The primary outcome was fulfillment of an ERO prescription within seven days of discharge. Multilevel logistic regression estimated associations between patient, surgical, anesthetic, and hospital factors and filling an ERO prescription. Variation was quantified using variance partition coefficients (VPCs) and median odds ratios (MOR) with 95% confidence intervals (CI), based on random effects. RESULTS: Among 229,995 knee and hip arthroplasty procedures, 27,915 (12.1%) patients filled a new ERO prescription post-discharge. Male sex (OR 1.14, 95% CI 1.09-1.19), preoperative opioid exposure (Opioid Naïve-Exposed-Tolerant (ONET) Score 2 OR 1.21, 95% CI 1.15-1.27; ONET 3 OR 1.38, 95% CI 1.20-1.58), and ASA 3 status (OR 1.07, 95% CI 1.01-1.12) increased odds of filling a new ERO prescription. Neuraxial anesthesia (OR 0.79, 95% CI 0.74-0.84), peripheral nerve block (OR 0.84, 95% CI 0.79-0.89), and acute pain service involvement (OR 0.77, 95% CI 0.70-0.85) were protective against filling a new ERO prescription. Substantial variation was found across hospitals (VPC 46%, 95% CI 0.4-0.54; MOR 9.3, 95% CI 6.57-15.27) and surgeons (VPC 26%, 95% CI 0.24-0.26; MOR 5.3, 95% CI 4.63-6.11), with minimal anesthetist-level variation (VPC 1%, 95% CI 0.010-0.011; MOR 1.4, 95% CI 1.36-1.46). Patient-level factors explained a minority of variation. CONCLUSIONS: One in ten patients fills an ERO prescription after total hip or knee arthroplasty, a practice with high variation that is predominantly driven by institutional and surgical practice patterns rather than patient factors. Future research should explore institutional stewardship, standardized discharge protocols, and multidisciplinary engagement to reduce unnecessary postoperative exposure to EROs.