Abstract
BACKGROUND: Opioid analgesics are commonly used for controlling pain after total knee or hip replacement. However, it is unclear how much opioid should be prescribed at discharge after total hip and knee replacement surgery to optimize pain management but minimise adverse events. To determine the acceptability and feasibility of a trial comparing a reduced and standard opioid regimen following discharge from total knee or hip replacement. METHODS: This pilot randomized controlled trial recruited participants from the pre-admission clinic of a metropolitan hospital in Sydney. All participants received a non-opioid regimen of naproxen 500 mg 12 hourly for 7 days, and paracetamol 1000 mg 6 hourly daily for 14 days. Participants were randomly allocated to the 'standard' group (oxycodone 5 mg taken as needed, maximum recommended frequency of 4 hourly, 20 tablets dispensed) or the 'reduced' group (received half the amount of oxycodone, taken half as frequently) at hospital discharge. Primary outcomes were screening to recruitment rate, percentage completing follow-ups, and acceptability of the trial procedures. Acceptability was measured quantitatively at weeks 1 and 2 post-discharge and qualitatively by interview at 6 weeks post-discharge. Adverse events were collected up to 6-weeks post-discharge. RESULTS: In four months, we screened 254 people, of which 72 were eligible and 53 were recruited (recruitment rate = 21%). 93% participants completed all their follow up surveys. Participants scored the trial intervention between neutral and acceptable (3.6/5 for both groups and weeks). 39 interviews were conducted where both clinicians and patients reported strong support for the pilot trial design. Few adverse events occurred across both groups, the most common being constipation. CONCLUSIONS: This pilot trial indicated that a full-scale trial would be feasible and acceptable. Such a trial could provide evidence of comparative effectiveness for the reduced opioid regimen in this population. TRIAL REGISTRATION: The trial was pre-registered in Australian New Zealand Clinical Trials Registry (ACTRN12623001070628).