None listed
Conditions
Brief summary
Patients who have knee joint replacement operations can be in a lot of pain afterwards. The doctor will often use a special local anaesthetic injection called a nerve block to try to reduce this pain. These injections use an ultrasound machine to find the nerves. By injecting local anaesthetic right next to these nerves, patients can have less pain after the operation compared to patients who only have local anaesthetic injected into the surgical wound. The main side effect of some of the nerve blocks is leg weakness. It is important that a patient can get up and walk as soon as possible after a knee operation. Too much leg weakness can stop this from happening or lead to a patient falling over and injuring themselves. A nerve block called an “adductor canal block” is currently being used in patients having knee operations. This nerve block can result in a similar amount of pain relief as other nerve blocks but causes much less leg weakness. It can be given either as a one-off injection or by placing a very fine tube, a catheter, next to the nerve and giving a continuous drip of local anaesthetic. Although one-off injections are easier and quicker to perform, the pain relief effects do not last as long as the catheter method. When performing a nerve block, a steroid medication called dexamethasone can be mixed with the local anaesthetic solution to make the pain relief effects last longer. Studies have shown that dexamethasone makes the nerve blocks used in shoulder and arm surgery last longer. Whether dexamethasone would have the same effect on an adductor canal block is not known as it has not been studied before. If dexamethasone was shown to make an adductor canal block last longer, it could be used in knee surgery patients to keep them comfortable for a longer time after their operation. Intravenous dexamethasone (given via a drip in a vein) is widely used for the management of nausea and vomiting associated with general anaesthesia, although it is officially off-license for use via a drip. We intend to do a small pilot study to find out whether dexamethasone has an effect on how long an adductor canal block lasts. This will involve doing an adductor canal block, with or without dexamethasone, on patients already having knee joint replacement surgery. If we can show that using dexamethasone in adductor canal blocks can make the block last longer, we will then plan to do a larger study comparing the one-off adductor canal block with dexamethasone against the adductor canal block catheter.
Interventions
All elective total knee arthroplasty patients will recieve an adductor canal block as part of a multi-modal regional anaesthetic technique consisting of an adductor canal block, spinal anaesthetic and local infiltration analgesia. The duration of sensory block of the adductor canal block will be compared between patients recieving no dexamethasone, perineural dexamethasone added to the block and dexamethasone given intravenously.
Adductor canal nerve blocks are to be performed before spinal ana
All elective total knee arthroplasty patients will recieve an adductor canal block as part of a multi-modal regional anaesthetic technique consisting of an adductor canal block, spinal anaesthetic and local infiltration analgesia. The duration of sensory block of the adductor canal block will be compared between patients recieving no dexamethasone, perineural dexamethasone added to the block and dexamethasone given intravenously. Adductor canal nerve blocks are to be performed before spinal anaesthesia using ultrasound, and the corresponding “numb patch” on medial malleolus marked out using a skin marker. After assessment for eligibility and informed consent at pre-assessment, patients will be randomised into one of three groups. Group P (Placebo) - Adductor canal block with 75mg ropivicaine (10mls) and 2mls 0.9% normal saline in block mixture. 2mls 0.9% Normal saline intravenously. Group N (Peri-neural) - Adductor canal block with 75mg ropivicaine (10mls) and 8mg (2mls) 0.9% dexamethasone in block mixture. 2mls 0.9% Normal saline intravenously. Group IV (Intravenous) - Adductor canal block with 75mg ropivicaine (10mls) and 2mls 0.9% normal saline in block mixture. 8mg (2mls) dexamethasone intravenously. Adductor canal block administered at time = 0hrs. Expected duration of adductor canal block = 6-12hours Expected duration of adductor canal block with dexamethasone = 6-24hours. All groups will receive the following. *Spinal anaesthesia with 2.4-2.6ml 0.5% hyperbaric bupivacaine with 100mcg intrathecal morphine. (Administered at time = 30 mins, spinal duration = up to 4 hours, intrathecal morphine duration = up to 24 hours). *Intra-articular local anaesthetic infiltration (225mg ropivicaine, 0.5mg adrenaline +/- 30mg ketorolac made up to 100ml 0.9% saline). (Administered at time = 1 hour, duration = up to 12 hours). *2mg tropisteron, 0.25mg droperidol, cyclizine 50mg intravenously for anti-emesis. (Antiemetics administered at time = 30mins, duration of antiemetics = 4-6hours). *Sedation with propofol and/or midazolam and fluid management at the discretion of the anaesthetist. (Administered at time = 30mins, duration = duration of surgery). *Postoperative patient controlled analgesia with morphine. (Administered at time = end of surgery, duration = 3 days). Overall duration of surgery = 1-3 hours.
Sponsors
Fremantle Hospital and Health Services
Study design
Allocation
Randomised controlled trial
Intervention model
Parallel
Primary purpose
Treatment
Masking
Blinded (masking used) (Subject, Caregiver, Investigator, Outcomes Assessor)
Eligibility
Sex/Gender
All
Age
18 Years to No maximum
Healthy volunteers
No
Inclusion criteria
Elective primary total knee replacement Age >18 Spinal anaesthesia as part of technique Intra-articular local anaesthetic infiltration
Exclusion criteria
Allergy to local anaesthetic or dexamethasone Allergy to morphine Currently on oral or IV steroids Complex chronic pain issues Severe renal or hepatic impairment Pregnancy Patient <55kg weight Uncontrolled diabetics Contraindication to nerve blockade
Outcome results
None listed