Title: Perioperative Analgesia for Knee Arthroplasty: A prospective randomised trial.
Funder: Department of Health (England)

Abstract: A total knee replacement is the most common joint replacement surgery performed in the NHS, with 82,000 performed in 2010. Good pain relief with minimal physiological disturbance is important for postoperative knee rehabilitation and may influence the overall outcome of knee arthroplasty surgery. Recently, the use of intra-operative, peri-articular local administration of analgesics has gained in popularity. Peri-articular infiltration has the advantage of delivering drugs directly to the sources of pain thereby avoiding systemic side effects. However, there is currently no definitive evidence which directly compares peri-articular infiltration versus standard femoral nerve block. Research Question and Aims: This is a pragmatic, double-blind, single-centre randomised controlled trial of peri-articular local administration of analgesics versus femoral nerve block in total knee replacement. To answer the following research question: “In patients undergoing a total knee replacement ( population ), is there a difference in patient reported pain score on the Visual Analogue Score (VAS) ( outcome ) prior to physiotherapy day 1 post operatively between patients managed with a multi-modal, peri-articular knee infiltration( intervention ) compared patients managed with standard femoral nerve block? “( Comparison ). Aims: The primary aim is to quantify and draw inferences on the efficacy of the treatment groups based on observed differences in primary and secondary outcome measures prior to discharge. The secondary aim is to assess the function and health outcome at 6 weeks post-operation. Plan of Investigation: All patients undergoing an elective primary unilateral total knee arthroplasty (TKA) under the care of an orthopaedic consultant at University Hospitals Coventry and Warwickshire NHS Trust are potentially eligible for the trial. The trial will employ a 1:1 randomisation sequence, stratified by mode of anaesthetic, employed using a remote, telephone randomisation service at Warwick clinical trials unit. Patients will be followed up by a blind assessor prior to discharge, and at 6 weeks after treatment via a postal questionnaires. The primary outcome measure is a patient reported pain assessment, the VAS (Visual Analogue Scale) which will be conducted at 8.30 am prior to physiotherapy on day 1 post-operatively. The secondary outcome measures will be additional VAS collected at 8.30 am prior to physiotherapy on day 2, total use of “as required” analgesia in 48 hours , Ordinal pain score (routinely collected every 6 hours for the first 48 hours), independent routine functional physiotherapist assessment on day one and two postoperatively. The Oxford knee score (OKS), EuroQol (EQ-5D) will be recorded pre operatively and at 6 weeks. All complications will be reported. These will be analysed by a statistician who will also be blind to the treatment allocations. Potential Benefits: Traditional analgesia following total knee replacement has provided good analgesia, but affects post-operative mobility and days to discharge. However, a peri-articular technique appears to offer several advan­tages over traditional methods, since the analgesia affects only the surgical area with limited interference of the muscle strength. Thus, easier rehabilitation of the operated extremity and earlier discharge from the hospital can be expected. This trial will provide authoritative high-quality evidence of efficacy of this new technique.


Research activity codes: 6.1 PHARMACEUTICALS
Health categories: MUSCULOSKELETAL