None listed
Conditions
Brief summary
The primary aim of this study is to quantitatively measure, in healthy controls, the effects of a pharmacologic agent in attenuating experimentally induced responses simulating the clinical characteristics of lateral epicondylalgia (“tennis elbow”). The primary hypothesis to be tested in this study is: in comparison with a placebo intervention, a pharmacological intervention targeting processes of central sensitisation via blockade of the N-methyl-D-asparate (NMDA) receptor will attenuate the somatosensory and motor effects of experimentally induced pain in healthy control subjects with simulated characteristics of clinical lateral epicondylalgia Lay version: In the experiment we will investigate what happens to forearm muscle function and pressure pain sensitivity when given a lozenge containing either an active medication or placebo prior to experimentally induced pain in those muscles. These muscles are involved in “tennis elbow” problems in occupational and sporting settings. What does it involve? This experiment will be conducted over two days taking about 1.5 hour per session. At the first session you will be given a lozenge (either placebo or an active drug) 1 hour prior to undertaking an intense bout of eccentric exercise in your non-dominant arm. One day later, a muscle in your exercised arm will be injected with hypertonic saline. This injection may generate a short period of muscle pain. Before and after each session a number of measures will be taken: 1. Pressure pain sensitivity at sites around forearm muscles and tendons using a device to measure mechanical pressure sensitivity (pressure algometer); 2. muscle strength of specific elbow muscles. These measures will also be repeated at Day 1 during the hypertonic saline-induced pain.
Interventions
Ketamine (25mg sublingual) will be administered prior to an intense bout of eccentric exercise used to induce delayed onset muscle soreness (DOMS) in the wrist extensors of healthy control subjects. Verum and placebo lozenges will look identical to maintain double blinding. Twenty four hours post-exercise, subjects will receive an infusion of hypertonic saline (1.0mls @ 5%) into the extensor carpi radialis brevis muscle.
Methodology: 1. Induced delayed onset muscle soreness:
The exercise protoc
Ketamine (25mg sublingual) will be administered prior to an intense bout of eccentric exercise used to induce delayed onset muscle soreness (DOMS) in the wrist extensors of healthy control subjects. Verum and placebo lozenges will look identical to maintain double blinding. Twenty four hours post-exercise, subjects will receive an infusion of hypertonic saline (1.0mls @ 5%) into the extensor carpi radialis brevis muscle. Methodology: 1. Induced delayed onset muscle soreness: The exercise protocol will be performed using the isokinetic mode of the Kin-Com dynamometer (Chattecx Corp. Hixson, TN) as previously described (Slater et al. 2005). The total exercise period will be 25 minutes, with 5 bouts each of 5 minutes duration (60 repetitions per bout), with each bout separated by a minute rest interval; 2. Intramuscular infusion of hypertonic saline: Hypertonic saline will be infused using a computer-controlled pump (IVAC, model 770, USA), with a 10 ml plastic syringe (Graven-Nielsen et al. 1997). A tube (IVAC G30303, extension set with polyethylene inner line) will be connected from the syringe to the disposable needle (27G, 20mm). A bolus injection of 1.0 ml of sterile hypertonic (5.8%) saline will be injected over 40 seconds. The duration of the total experimental time will therefore be approximately 26 hours with the drug intervention (if active) peaking at 45 minutes after administration. Subjects will partake in one experimental session only and receive either ketamine or placebo, NOT both.
Sponsors
Dr Helen Slater
Study design
Allocation
Randomised controlled trial
Intervention model
Parallel
Primary purpose
Prevention
Masking
Blinded (masking used)
Eligibility
Sex/Gender
All
Age
18 Years to 35 Years
Healthy volunteers
No
Inclusion criteria
Healthy controls; comprehensive musculoskeletal physical examination will be performed on both upper limbs to ensure full pain free range of elbow and wrist motion, and no abnormal tenderness to palpation of the soft tissues in the extensor muscles of the forearm and wrist (Haker 1993), or abnormally reduced muscle length.
Exclusion criteria
Involvement of the contralateral arm, cervicothoracic spinal pathology, other upper limb musculoskeletal disorders or neurological disorders.
Outcome results
None listed