Osteoarthritis
Conditions
Keywords
Arthroplasty, Analgesia
Brief summary
Primary total knee arthroplasty (TKA) is commonly associated with moderate to severe early post-operative pain. The primary aim of this study was to investigate the impact of either a single-shot femoral nerve block (FNB) or intrathecal diamorphine (ID) on post-operative pain after TKA The Null Hypothesis is that there is no difference in the post operative pain relief provided for TKA by a single-shot femoral nerve block (FNB) as compared to intrathecal diamorphine (ID).
Detailed description
In 2008, the Prospect Working Group, a multidisciplinary expert panel, published their consensus guidelines on the relative merits of different anaesthetic and analgesic techniques for TKA based on a review of the available published literature up to 2005. These guidelines supported the use of general anaesthesia combined with a femoral nerve block for surgery and postoperative analgesia, or alternatively spinal anaesthesia with local anaesthetic combined with spinal morphine. The preference for femoral nerve block in favour of intrathecal opiates was as a consequence of the greater potential for side effects with the latter technique. The authors conceded that there were a lack of well-conducted studies on this subject, graded their recommendations as level D (expert opinion), and concluded further research was needed. Consequently there has been debate around the conclusions drawn and clinicians have not universally accepted the recommendations. Most researchers to date have focused on short-term outcomes such as static pain scores and/or opiate consumption. It is also important however to investigate dynamic pain scores, patient reported outcomes, the attainment of rehabilitation goals, length of stay and longer term functional outcomes. In addition, the use of the total pain relief score (TOTPAR) as described by Cooper and Beaver, assesses the cumulative response to treatment. This is a well validated area under the time-analgesic effect curve (AUC) derivation for pain relief which is commonly used by meta-analyses of analgesic interventions. The aim of this study is to investigate all these endpoints in patients receiving a single-shot femoral nerve block (FNB) for TKA as compared to intrathecal diamorphine (ID), a more commonly used spinal opiate in United Kingdom anaesthetic practice.
Interventions
PROCEDUREFemoral Nerve Block with levobupivicaine
A single injection femoral nerve block (FNB) performed in the supine position with a 50mm insulated needle (NanoLine, Pajunk, Geisingen, Germany) and peripheral nerve stimulator set at 1Hz with pulse width 0.1ms. Once a quadriceps muscle twitch is identified at a stimulated current between 0.2 and 0.5mA, 20mls of 0.375% levobupivacaine (75mg) is injected in fractionated amounts after negative aspiration
PROCEDUREIntrathecal injection of diamorphine
500mcg of intrathecal diamorphine (ID) (dissolved in 0.5mls normal saline)
Sponsors
Royal Devon and Exeter NHS Foundation Trust
Study design
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
TREATMENT
Masking
SINGLE (Investigator)
Eligibility
Sex/Gender
ALL
Age
16 Years to No maximum
Healthy volunteers
No
Inclusion criteria
* Adult patients scheduled for primary unilateral Total Knee Arthroplasty
Exclusion criteria
* Uni-compartmental surgery, bilateral surgery, contra-indication to spinal anaesthesia or peripheral nerve block (anticoagulation, hydrocephalus, raised intracranial pressure), allergy to local anaesthetics or diamorphine, malignant hyperthermia or other concerns over general anaesthesia, chronic opiate use and chronic pain medication use (e.g. gabapentin, pregabalin, amitriptyline).
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Median pain score (NRS: see below) at rest | Over 72 hours post operatively | Numerical rating scale (NRS) score (where 0 = no pain and 10 = worst possible pain) assessed at times 3, 6, 12, 24, 48 and 72 hrs postoperatively. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Pain on movement | At 3 hrs postoperatively | Numerical rating scale (NRS) score (where 0 = no pain and 10 = worst possible pain) |
| Pain at rest | At 3 hrs postoperatively | Numerical rating scale (NRS) score (where 0 = no pain and 10 = worst possible pain) |
| Morphine consumption | Over 72 hrs postoperatively | Cumulative consumption in milligrams |
Other
| Measure | Time frame | Description |
|---|---|---|
| Quality of recovery score 40 | Day 2 post operatively | Quality of recovery score is a 40 point patient reported outcome measure devised by Paul Myles and reported in the British Journal of Anaesthesia 84 (1): 11-15 (2000). This psychometric tool assess emotional state, physical comfort, psychological support, physical independence and pain grading each out of 5 (0= lowest score and 5 = highest score). We ranked total score as extremely poor (0-40), poor (41-80), satisfactory (81-120), good (121-160) or excellent (161-200). |
| Total Pain Relief Score (TOTPAR) | Day 1,2 and 3 post-operatively | Percentage of the maximum total pain relief was calculated by dividing the total pain relief (TOTPAR) over the three days by the maximum potential pain relief and expressed as a percentage (%maxTOTPAR) |
| Functional health outcome measure | At 6 weeks post-operatively | The Oxford Knee Score (OKS) is a 12-item patient-reported questionnaire specifically designed and developed to assess function and pain after total knee arthroplasty. It is short, reproducible, valid and sensitive to clinically important changes. The OKS was designed to be completed by the patient thus minimising potential bias unwittingly introduced by surgeons when assessing the results themselves. The PRO was designed and developed by researchers within Public Health and Primary Health Care at the University of Oxford in association with surgical colleagues at the Nuffield Orthopaedic Centre. The OKS at 6 weeks was compared to the preoperative OKS to describe the change in functional outcome. |
| Physical health outcome | A 6 weeks post-operatively | EuroQol 5 Dimensions Score/Visual Analogue Score (EQ-5D™/VAS). This is a standardised instrument for use as a measure of health outcome. It uses a patient self reporting 5 point (3 level) questionnaire and visual analogue scale to measure health. Health improvement at 6 weeks was assessed by comparing with pre-operative scores. |
Countries
United Kingdom
Outcome results
None listed