Effect of Volume of Local Anesthetic for Adductor Canal Block on Quadriceps Muscle Function: A Dose Finding Study
Trial Snapshot
- Phase
- Phase 3
- Status
- Completed
- Enrollment
- 26
- Locations
- 1
- Primary Endpoint
- The primary outcome will be the EV50 of anesthetic volume needed to produce >30% reduction of pre-injectate quadriceps strength at 20 minutes following adductor canal block.
Study Overview
Brief Summary
Adductor canal block is commonly offered to provide pain relief following knee surgery with the hope that they cause less leg weakness than traditionally performed femoral nerve block. Infrequently, adductor canal blocks also result in leg weakness thereby potentially limiting the advantages of the technique. Investigators want to find out the effective dose for a 30% response (volume of local anesthetic which would result in clinically significant weakness of the leg)
Detailed Description
This is a sequential design method of binary response variables for determination of the dose associated with the 50% point along the dose-response curve required to cause quadriceps weakness following adductor canal bock for knee arthroscopic procedures. It is a Dixon and Massey up-and-down study design.
The primary objective is finding the EV50 of 0.5% ropivacaine needed to cause a 30% reduction in quadriceps function 20 minutes post-procedure.
This study design was selected to allow the estimation of the target dose associated with the given outcome of quadriceps weakness. The study will be performed on 36 patients undergoing knee arthroscopic procedures. The quadriceps strength on both legs will be evaluated preoperatively by the physiotherapist.
The quadriceps function will be measured using a hand held dynamometer (HDD). For quadriceps muscle strength evaluation, investigators will place the patient in a seated position with the knees flexed 60 degrees. To avoid interrater reliability (when the strength of the subject overcomes the strength of the tester) investigators will fix the HHD for quadriceps evaluation. A non-elastic strap with Velcro closures will be used to fix the HHD. The Velcro strap will be attached to a chair leg and around the subject's ankle, perpendicular to the lower leg. The HHD will be placed under the Velcro strap, on the anterior surface of the tibia, 5 cm above the transmalleolar axis.
Subjects will be educated about the procedure before outcome assessments. They will be instructed to take 2 seconds to reach maximum effort, maintain this force for 3 seconds, and then relax. For each assessment, the subjects will perform 3 consecutive contractions, separated by a 30-second pause between each trial. Investigators will use the mean value at each time point for calculations, and calculated muscle strength as percent of baseline value. An independent investigator not involved in the performance of the block will assess the quadriceps muscle function before, 20 minutes and then 4 hours after the block.
Study Design
- Study Type
- Interventional
- Allocation
- Na
- Intervention Model
- Single Group
- Primary Purpose
- Diagnostic
- Masking
- None
Eligibility Criteria
- Ages
- 16 Years to 60 Years (Child, Adult)
- Sex
- All
- Accepts Healthy Volunteers
- Yes
Inclusion Criteria
- •Male and females
- •Age 16-60 years
- •Scheduled surgery
- •Knee arthroscopy
- •ASA Class I - III
Exclusion Criteria
- •Ipsi- or contralateral leg weakness
- •Preoperative neurological deficits
- •Narcotic dependent (opioid intake more than 3 months)
- •Chronic pain conditions
- •Significant cardiac and respiratory disease
- •Coexisting hematological disorder or with deranged coagulation parameters
- •Pre-existing major organ dysfunction such as hepatic and renal failure.
- •Psychiatric illnesses
- •Emergency surgery
- •Lack of informed consent
- •Allergy to any of the drugs used in the study
Arms & Interventions
Knee arthroscopic patient
- Male and females 2) Age 16-60 years 3) Scheduled surgery 4) Knee arthroscopy 5) ASA Class I - III
Volume finding study to follow up-and-down design using a single cohort of patients. Intervention of patient will be dependent on effect of previous patients dose of and response to Ropivacaine 0.5% injectate.
Intervention: Ropivacaine 0.5% (Drug)
Outcomes
Primary Outcomes
The primary outcome will be the EV50 of anesthetic volume needed to produce >30% reduction of pre-injectate quadriceps strength at 20 minutes following adductor canal block.
Time Frame: Percentage difference before block and at 20minutes
Measured by handheld dynamometer
Secondary Outcomes
- Reduced sensation to pin-prick around the anteromedial aspect of the knee(20 minutes post-block)
- Post-operative quadriceps muscle function(Percentage difference before block and at 4 hours following block)
Investigators
Rakesh Sondekoppam Vijayashankar
Principal Investigator
Lawson Health Research Institute