The Prevalence of Neuropathic Pain Pathophysiology Associated With Ankle Fracture

Chronic Pain Grading Scale

Time frame: 6-9 month

Chronic Pain Grading Scale (CPGS) will be used to determine if fracture patients have pain in the chronic phase of injury (6-9 month visit). The pain intensity subscale will be used to categorize participants into those with and without chronic pain. This score is the sum of three questions (current pain, worst pain, average pain over last month), each scored on an 11-point Likert scale with responses ranging from 0-10 for a maximum of 30 points. The participant will be asked to report only on pain related to the site of fracture. Participants scoring 1-30 on the characteristic pain intensity score in the last month at the site of fracture will be classified as having chronic pain related to the fracture. Patients reporting no pain (0) at the site of fracture in the last month will be classified as having no chronic pain.

Douleur Neuropathique (Neuropathic Pain) 4

Time frame: 2 weeks to 1 year

Douleur Neuropathique (Neuropathic Pain) 4 (DN4). The DN4 is a validated and reliable screening tool for neuropathic pain consisting of 10 items. The first 7 items relate to pain quality (i.e., sensory and pain descriptors) are based on interview with the patient. The last 3 items are based on clinical examination and assess hypoesthesia to touch, and hypoesthesia to prick and brushing. The items of the DN4 are scored based on a yes (1 point)/no (0 points) answer. This leads to a score range of 0-10. The cut-off value for the classification of neuropathic pain is a total score of 4 of 10.72 The DN4 has been used to identify NP in ankle fracture patients.

Assessment of Chronic Regional Pain Syndrome (CRPS)

Time frame: 2 weeks to 6-9 months

Assessment of Chronic Regional Pain Syndrome (CRPS). Presence of CRPS will be assessed in study participants beginning at the 6-8 week follow-up visit and all subsequent visits. Assessment of CRPS at earlier timepoints cannot be done rigorously as pain, motor, temperature and other changes comprising in part the CRPS diagnostic criteria can be related to the recent trauma. In addition to the QST procedures, a validated CRPS sign and symptom checklist will be administered by the study coordinator containing items in the 4 symptom and 4 sign categories needed to establish a CRPS diagnosis. For this study the investigators will employ the more rigorous CRPS Research Criteria (all symptom categories positive and 2/4 sign categories).

Central Sensitization measure

Time frame: 5-9 weeks to 6-9 months

Central Sensitization measure: The most common quantitative sensory test used to measure central sensitization in human experimental studies is temporal summation of pain (TS).TS will be administered on the skin proximal to the level of injury and the contralateral uninjured side using a nylon monofilament (Touchtest Sensory Evaluator 6.65) calibrated to bend at 300g of pressure. As in previous studies, participants will rate the perceived pain intensity of a single contact of the monofilament using a 0 to 100 numeric rating scale. Then, participants will provide another pain rating following a series of 10 contacts administered at a rate of 1 contact per second, applied to the body site within an area of 1 cm2. The difference between pain ratings for the single versus multiple contacts reflects temporal summation of mechanical pain. Two trials will be administered.

Pain Inhibitory Test

Time frame: 5-9 weeks to 6-9 months

Pain Inhibitory Test. Conditioned pain modulation (CPM) will be assessed by determining the ability of a cold pressor task to diminish pressure pain thresholds applied at a separate body site. For the conditioning stimulus, participants will immerse their non-affected hand up to the wrist in a cold water bath maintained at 10 degrees C for up to 1 minute or until they report intolerable pain.The test stimulus will be two trials of pressure pain thresholds (PPTs) administered on the left forearm. The experimenter will apply a slow constant rate of pressure and the participant will press a button when the sensation first becomes painful, at which time a device records the pressure. Three consecutive measurements with intervals of 20s will be obtained pre- and post- the conditioning stimulus.

What is a clinical trial?

A clinical trial is a research study that tests new medical treatments, drugs, devices, or procedures to determine their safety and effectiveness. Trials are carefully designed and monitored to protect participants while advancing medical knowledge.

Is it safe to participate?

Clinical trials follow strict safety guidelines and ethical standards. Trials must be reviewed and approved, and participants are closely monitored by medical professionals throughout the study. You can withdraw at any time if you choose.

Will I be compensated?

Many clinical trials offer compensation for your time, travel expenses, and inconvenience. The specific compensation varies by study and will be discussed during the screening process. All study-related medical care is typically provided at no cost to participants.

Will I receive a placebo instead of treatment?

When effective treatment exists, participants typically receive either the standard treatment plus the study intervention, or the standard treatment plus placebo. You would not be denied effective care. Placebos are primarily used when no proven treatment is available, or in addition to standard care. Your trial consent form will clearly explain what treatments you may receive.

Can I leave a trial if I change my mind?

Absolutely. Participation in clinical trials is completely voluntary. You have the right to withdraw from the study at any time, for any reason, without penalty or loss of benefits to which you are otherwise entitled.

How long does a clinical trial last?

Trial duration varies widely depending on the study design and purpose. Some trials last just a few weeks, while others may continue for months or years. The study coordinator will provide specific timeline information during your screening call.