Pain profiles and opioid consumption following joint replacement surgery: a prospective observational cohort study.

Purpose: We sought to analyze postoperative discharge opioid prescription, consumption, and pain over three months following total hip arthroplasty (THA) and total knee arthroplasty (TKA).

Methods: We conducted a prospective observational study in patients undergoing THA and TKA at two centres in Toronto, ON, Canada. We contacted study participants at two, six, and 12 weeks after discharge to collect data on analgesic satisfaction, pain relief, time point of stopping opioids, quantity of unconsumed opioid pills, quality of pain, and mental health. We also evaluated patient factors that may have contributed to a higher opioid consumption or dissatisfaction with the analgesic prescription at six weeks.

Results: The median [interquartile range] opioid pill count prescribed at the time of discharge for the 443 participants was 60 [50-80]. At 12 weeks after surgery, 33.9% of participants had more than one-third of their prescribed quantity remaining. Three-quarters of the cohort indicated that pain relief after arthroplasty was appropriate at all postoperative follow-ups. The incidence of neuropathic pain reduced from 24.1% before TKA or THA to 4.3% at 12 weeks after arthroplasty. Female sex (odds ratio [OR], 1.78; 95% confidence interval [CI], 1.08 to 2.95; P = 0.03), a history of preoperative opioid use (OR, 2.46; 95% CI, 1.25 to 5.1; P = 0.01), and TKA vs THA (OR, 2.46; 95% CI, 1.47 to 4.17; P = 0.001) were associated with higher opioid consumption at six weeks after arthroplasty.

Conclusion: A discharge prescription of 60 opioid pills may be excessive for patients undergoing THA or TKA. Identifying patients with risk factors for higher postoperative opioid consumption may result in more appropriate analgesic regimens.