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Trial to Compare Femoral Nerve Block With Local Anaesthetic Injection for Post-operative Pain After Knee Replacement.

Not Applicable
Completed
Conditions
Arthritis Knee
Interventions
Procedure: Femoral nerve block
Procedure: Local Infiltration Analgesia
Procedure: Sub arachnoid analgesia
Procedure: Sedation or general anaesthesia
Drug: Pre-medication
Drug: Intra-operative medication
Drug: Post-operative analgesia - morphine
Drug: Post-operative analgesia - ibuprofen and paracetamol
Drug: Regular anti emetics
Registration Number
NCT02288923
Lead Sponsor
Royal Devon and Exeter NHS Foundation Trust
Brief Summary

Pain after a knee replacement can impair recovery and use of the new knee. Having an injection to numb the femoral nerve is known to give good pain relief after the operation but may lead to slower mobilisation as it also prevents the patient from moving the knee. Recent studies have shown that infiltration of local anaesthetic (LIA) within the new knee joint may also give good pain relief. The null hypothesis is that there is no difference in primary or secondary outcome measures between femoral nerve block and LIA, as anaesthetic techniques for knee replacement.

Detailed Description

Knee pain and stiffness is a common problem which can sometimes be improved by inserting a replacement knee joint. An anaesthetist is a doctor who specialises in looking after patients undergoing surgery, and there are a variety of different anaesthetics which can be used for knee replacement surgery. These include general anaesthesia (going to sleep), and spinal or epidural anaesthesia (where pain killers are injected into the back, resulting in temporarily numb legs). Pain killers can also be injected around the nerves which supply the leg, or around the site of the operation itself, combined with general or spinal anaesthesia if required.

Over the years, multiple different combinations of these techniques have been tried. All have advantages and disadvantages. Generally, those which completely numb the leg after the operation often cause weakness which interferes with movement. Although the patient will have no pain, getting up and around with the physiotherapist is crucial and the weakness can delay recovery. However, excessive pain can also interfere with movement. There is therefore a balance to be struck between pain and weakness, and the choice of anaesthetic technique is key.

Researchers previously conducted a study at the Royal Devon and Exeter Hospital which compared the effects of two techniques; the use of diamorphine in a spinal injection, and the injection of pain killer around a nerve supplying the leg (femoral nerve block, FNB). Whilst the research showed that FNB gave better pain relief, there are still concerns that it causes weakness which may interfere with movement. A newer technique has evolved over recent years in which pain killer is injected directly around the knee during the operation. This is known as local infiltration analgesia (LIA) and the potential advantages are that it is simple, safe and does not cause leg weakness.

If research shows that LIA provides adequate pain relief without weakness, it may be a better option to use routinely, rather than FNB. The primary outcome measure is the amount of morphine used in the first 48 hours. The secondary outcome measures are the Total Pain Relief Score (TOTPAR), post operative pain scores, the ability to achieve set rehabilitation goals, readiness for discharge and qualitative data on patient recovery and satisfaction.

Recruitment & Eligibility

Status
COMPLETED
Sex
All
Target Recruitment
199
Inclusion Criteria

All adult patients presenting for primary knee arthroplasty under the care of the Exeter Knee Unit Consultants Messrs Toms, Eyres, Cox, Mandalia, Schrantz.

Exclusion Criteria
  1. Total knee arthroplasty for trauma

  2. Unicompartmental surgery

  3. Bilateral surgery

  4. Contra indication to spinal anaesthesia or peripheral nerve blocks (anticoagulation, hydrocephalus, raised intracranial pressure, peripheral neuropathy)

  5. Allergy to local anaesthetics or morphine

  6. Chronic pain:

    • Under active follow up by chronic pain team
    • Chronic strong opiate use (morphine, oxycodone, buprenorphine, pethidine, methadone). Codeine, dihydrocodeine and tramadol are not included
    • Other chronic pain medications (including gabapentin, pregabalin or amitriptyline)
  7. Unable to adequately understand verbal explanations or written information given in English, or patients with special communication needs -

Study & Design

Study Type
INTERVENTIONAL
Study Design
PARALLEL
Arm && Interventions
GroupInterventionDescription
Femoral nerve blockRegular anti emeticsFemoral nerve block with 20ml 0.375% Levobupivacaine
Femoral nerve blockPre-medicationFemoral nerve block with 20ml 0.375% Levobupivacaine
Femoral nerve blockPost-operative analgesia - ibuprofen and paracetamolFemoral nerve block with 20ml 0.375% Levobupivacaine
Femoral nerve blockSub arachnoid analgesiaFemoral nerve block with 20ml 0.375% Levobupivacaine
Femoral nerve blockSedation or general anaesthesiaFemoral nerve block with 20ml 0.375% Levobupivacaine
Femoral nerve blockIntra-operative medicationFemoral nerve block with 20ml 0.375% Levobupivacaine
Femoral nerve blockFemoral nerve blockFemoral nerve block with 20ml 0.375% Levobupivacaine
Local Infiltration AnalgesiaLocal Infiltration AnalgesiaLocal infiltration of knee joint using 40ml of bupivacaine 0.25% with adrenaline 1:200 000, diluted to 150ml with saline 0.9%. This is then divided into thirds; 50ml into the posterior capsule before cementing, 50ml into the medial and lateral capsules and 50ml into subcutaneous tissues and in and around the vastus medialis and sartorius muscles (where it may block the saphenous nerve).
Local Infiltration AnalgesiaIntra-operative medicationLocal infiltration of knee joint using 40ml of bupivacaine 0.25% with adrenaline 1:200 000, diluted to 150ml with saline 0.9%. This is then divided into thirds; 50ml into the posterior capsule before cementing, 50ml into the medial and lateral capsules and 50ml into subcutaneous tissues and in and around the vastus medialis and sartorius muscles (where it may block the saphenous nerve).
Local Infiltration AnalgesiaPost-operative analgesia - morphineLocal infiltration of knee joint using 40ml of bupivacaine 0.25% with adrenaline 1:200 000, diluted to 150ml with saline 0.9%. This is then divided into thirds; 50ml into the posterior capsule before cementing, 50ml into the medial and lateral capsules and 50ml into subcutaneous tissues and in and around the vastus medialis and sartorius muscles (where it may block the saphenous nerve).
Femoral nerve blockPost-operative analgesia - morphineFemoral nerve block with 20ml 0.375% Levobupivacaine
Local Infiltration AnalgesiaSedation or general anaesthesiaLocal infiltration of knee joint using 40ml of bupivacaine 0.25% with adrenaline 1:200 000, diluted to 150ml with saline 0.9%. This is then divided into thirds; 50ml into the posterior capsule before cementing, 50ml into the medial and lateral capsules and 50ml into subcutaneous tissues and in and around the vastus medialis and sartorius muscles (where it may block the saphenous nerve).
Local Infiltration AnalgesiaPre-medicationLocal infiltration of knee joint using 40ml of bupivacaine 0.25% with adrenaline 1:200 000, diluted to 150ml with saline 0.9%. This is then divided into thirds; 50ml into the posterior capsule before cementing, 50ml into the medial and lateral capsules and 50ml into subcutaneous tissues and in and around the vastus medialis and sartorius muscles (where it may block the saphenous nerve).
Local Infiltration AnalgesiaSub arachnoid analgesiaLocal infiltration of knee joint using 40ml of bupivacaine 0.25% with adrenaline 1:200 000, diluted to 150ml with saline 0.9%. This is then divided into thirds; 50ml into the posterior capsule before cementing, 50ml into the medial and lateral capsules and 50ml into subcutaneous tissues and in and around the vastus medialis and sartorius muscles (where it may block the saphenous nerve).
Local Infiltration AnalgesiaPost-operative analgesia - ibuprofen and paracetamolLocal infiltration of knee joint using 40ml of bupivacaine 0.25% with adrenaline 1:200 000, diluted to 150ml with saline 0.9%. This is then divided into thirds; 50ml into the posterior capsule before cementing, 50ml into the medial and lateral capsules and 50ml into subcutaneous tissues and in and around the vastus medialis and sartorius muscles (where it may block the saphenous nerve).
Local Infiltration AnalgesiaRegular anti emeticsLocal infiltration of knee joint using 40ml of bupivacaine 0.25% with adrenaline 1:200 000, diluted to 150ml with saline 0.9%. This is then divided into thirds; 50ml into the posterior capsule before cementing, 50ml into the medial and lateral capsules and 50ml into subcutaneous tissues and in and around the vastus medialis and sartorius muscles (where it may block the saphenous nerve).
Primary Outcome Measures
NameTimeMethod
Morphine consumption in first post-operative 72 hours72 hours

The total amount of morphine consumed by the patient in the first 72 post-operative hours will be added up. If morphine has been given orally it will be counted as ⅓ the intravenous dose.

Secondary Outcome Measures
NameTimeMethod
Total pain relief scorePost op days 1, 2 and 3

Using the TOTPAR Scoring system (40. Cooper SA, and Beaver WT. A model to evaluate mild analgesics in oral surgery outpatients. Clin Pharmacol Ther. 1976, Aug;20(2):241-50.), patients will have their overall time measured when their pain was 70% controlled during post operative days 1, 2 and 3.

Post operative pain scoresDay 0 - 3 post op

Pain scores (using the numerical rating scale of 0-10) will be collected from patients at 12, 24, 48 and 72 hours post operation. A significant reduction would be a decrease of pain score at any of these times of 1.5 or more.

Achievement of rehabilitation goals1-4 days post operatively

Ability to achieve the rehabilitation goals of standing and getting out into a chair on post op day 1, walking to the bathroom at the end of day 2 and walking independently with crutches by the end of day 4

Readiness for dischargePost operative day 2-10

Time when patient is ready for discharge from the acute care hospital.

Patient satisfaction2nd post-operative day

Patients will be asked to fill out a patient satisfaction questionnaire "quality of recovery 40" (QoR-40) Myles PS, Weitkamp B, Jones K, Melick J, and Hensen S. Validity and reliability of a postoperative quality of recovery score: the QoR-40. British Journal of Anaesthesia. 2000;84(1):11-15.

Oxford Knee ScorePre op and 6 weeks post operatively

The Oxford Knee score will be completed by patients before and 6 weeks after their operation. http://www.orthopaedicscore.com/scorepages/oxford_knee_score.html

EuroQol 5 dimensions scorePre op and 6 weeks post operatively

EQ-5D-5L (EuroQol 5 dimensions score) will be used to measure the satisfaction the patient has with their knee in the fields of mobility, self-care, usual activities, pain/discomfort and anxiety/depression.

Trial Locations

Locations (1)

Royal Devon and Exeter NHS Foundation Trust

🇬🇧

Exeter, Devon, United Kingdom

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