Pilot RCT of Efficacy of Perineural Local Anesthetics and Steroids for Chronic Post-traumatic Ankle and Foot Pain

A Pilot Randomized Controlled Trial of Efficacy of Perineural Local Anesthetics and Steroids for Chronic Post-traumatic Neuropathic Pain in the Ankle and the Foot: The PREPLAN Study

Injections of local anesthetics (freezing) and steroids are often performed around injured nerves in individuals with nerve injury-related pain. The current standard of medical care is to inject a combination of local anesthetics and steroids around injured nerves, but there is no proof that this is better than injecting only local anesthetic, or even just sterile salt water. There is evidence to believe that injection of local anesthetic (without the steroid) can calm the injured nerve, and provide pain relief from a few days up to a few months. Injection of sterile salt water also has the potential to provide pain relief by breaking scar tissue around the nerve, thereby relieving compression. The aim of this study is to compare pain relief and possible adverse effects from these three different treatments for foot and ankle nerve pain relief.

All 30 participants will be recruited over 9 months from the Altum Health clinic at Toronto Western Hospital. 10 participants will be randomly assigned to each treatment. Each patient will receive 3 injections over 3 weeks or so. Participants will have an in-clinic follow-up at 1 month after the last injection, and a phone follow-up 3 months after the last injection.

This is a small-scale study, and information obtained from this study will help in planning and conduct of a larger study with more participants. The larger study will help determine the best possible option for injection in patients with nerve-related injury pain.

Inclusion Criteria:

1. Pain in foot in neuro-anatomically congruent location following trauma (including surgery) for more than three months
2. Physician-reported DN4 scoring confirming neuropathic pain (score > 3/10)
3. Average intensity of pain more than 3/10 on numerical rating score
4. Failed trial of appropriate doses of first line medications for neuropathic pain (anticonvulsants and/or antidepressants) for six weeks

Exclusion Criteria:

1. Age < 18 or age ≥ 80 years
2. Perineural or intra-articular steroid injections in the last 6 months
3. Allergy to local anesthetics and/or steroids
4. Ongoing litigation issues related to the patient's pain
5. Pregnancy
6. Coagulopathy or systemic infection
7. Peripheral neuropathy or myopathy, central neuropathic pain (e.g. post-stroke pain)
8. Infection in the ankle or foot
9. An unstable medical or psychiatric condition
10. Significant catastrophizing as indicated by pain catastrophizing scale (PCS) score equal to or more than 30/52