DEXRAR - DEXamethasone in Revision ARthroplasty:

A randomised, blinded, 2-group clinical trial

Background

Effective postoperative pain management is essential for the well-being and rehabilitation of the surgical patient. No “gold standard” exists for pain treatment after revison total knee arthroplasty (TKA) and combinations of different medications are used with virtually no evidence for combined analgesic efficacy. Paracetamol, non steroidal anti-inflammatory drugs (NSAID, fx ibuprofen) and local infiltration analgesia (LIA) are well documented as basis treatment for TKA. Glucocorticoids have previous shown effect on postoperative pain at primary TKA, but is not investigated in revision-TKA.

Objectives

The objective is to investigate the analgesic effect and safety of dexamethasone (glucocorticoide)  as a single dose after revision-TKA in combination with paracetamol, ibuprofen and local infiltration analgesia.

Intervention

The patients are randomised into to groups: A) 24 mg dexamethasone i.v. B) isototonic saline i.v.

Design and trial size

Placebo controlled, parallel 2-group trial with adequate centralised computer-generated allocation sequence and allocation concealment with varying block size. Blinding of assessor, investigator, caregivers and patients. Sample size: 108 eligible patients are needed to detect a difference of 11,3 mg morphine for the first 24 h postoperatively with a standard deviation of 20 mg, a type 1 error rate of 0,05 and a type 2 error rate of 0,20.

Inclusion and exclusion criteria

Patients scheduled for unilateral revision-TKA: Total and major partial revisions are included, i.e. revisions including the femoral and/or the tibial component(s); age > 18 yrs; ASA 1 - 3; BMI > 18 and < 45; women in the fertile age must have negative urine HCG pregnancy test; informed consent.

Primary outcome

Total need for morphine for the first 24 hours postoperatively administered as both patient controlled analgesia (PCA) and supplemental morphine administred at the post-anaesthesia unit for the first hour postoperatively

Secondary and exploratory outcome

Visual analogue scale (VAS) pain scores with active 45 degrees flexion of the knee, and at rest, at 6 and 24 hours postoperatively; blood sugar and timed up and go test at 24 hours postoperatively; quality of sleep first 24 hours; adverse events: nausea, vomiting, dizziness in the intervention period (0-24 hours); serious adverse events within 90 days after surgery.

Time schedule:

The study recruitet the first patient june 2017 and expect to finish 31. december 2018. Data analyses january to april 2019 and manuscript submission summer 2019.