Plantar fasciitis - Emerging treatments

Botulinum toxin type A

This drug may be effective via paresis of the injected muscles (abductor hallucis, flexor digitorum brevis, and quadratus plantae) or as a direct analgesic and/or anti-inflammatory agent. Multiple systematic reviews of varying quality have reported a benefit in both pain and function compared with controls, although individual studies have tended to be small and at high risk for bias.[49][73][74][75]

Cryosurgery

Cryosurgery is a minimally invasive technique that uses a small cryoprobe to percutaneously destroy pathological tissue or cells at temperatures reaching -70ºC ( -94ºF). A small ice ball, measuring approximately 0.5 cm in circumference, forms at the tip of the probe and freezes, causing axons and cellular elements to rupture, altering the pain pathway. One retrospective study demonstrated a 77.4% success rate in relieving pain in a sample of 137 feet belonging to patients who had not responded to 6 months of conservative management.[76] In a prospective study, testing 59 patients (61 heels) who failed prior conservative therapy, cryosurgery produced effective pain relief. Local anaesthetic was used, a small incision was made, and a 3 mm trocar inserted, allowing placement of the cryoprobe. Three minutes of freezing, 30 seconds of thawing, and another 3 minutes of freezing occurred. The site was irrigated and a dressing applied for 24 hours. One patient developed an abscess that resolved after oral antibiotic and debridement; 3 patients underwent open plantar fasciotomy because of resistant pain; 6 patients (10%) had a second cryoprobe procedure; 52.4% had complete resolution after one treatment. Trials comparing cryotherapy with surgery may be valuable in the future.[77]

Autologous blood injection

Autologous blood injection can potentially stimulate vascular ingrowth and fibroblast activity in cases of plantar fasciitis with recalcitrant pain. Multiple trials have compared this treatment with corticosteroid injection, although none have compared it to placebo. Systematic reviews have reported mixed results.[8][78] One retrospective cohort study comparing the outcomes for patients with chronic plantar fasciitis after autologous blood injection or extracorporeal shockwave therapy (ESWT) found that patients improved to a statistically significant extent with both treatments at 6 weeks, 3 months, and 6 months. However, no significant difference was seen between the two groups.[79] Future studies might consider using autologous blood injection in cases where corticosteroid fails, or comparing chronic pain scores in people receiving autologous blood injection versus placebo injection.

Platelet-rich plasma

Platelet-rich plasma injection (PRP) is an emerging technique in which autologous blood is drawn from the patient, centrifuged, and the plasma layer is drawn off and injected into the plantar fascia. Most studies to date have compared PRP to corticosteroids and multiple systematic reviews have provided relatively strong data in support of PRP as a potentially viable alternative to corticosteroid injection, especially given concerns about plantar fascia rupture after corticosteroid injection.[80][81][82][83][84][85] While PRP injections are generally well-tolerated with minimal complications, it is important to acknowledge the potential risks involved. These risks primarily stem from the injection procedure and may include infection, nerve injuries, pain at the injection site, and tissue damage.[83]

Dehydrated amniotic membrane

Dehydrated amniotic membrane injections are emerging as an alternative to more invasive surgical procedures in recalcitrant cases. The membrane is rehydrated in normal saline in a 1:1 ratio, and the solution is then injected intrafascially. Studies are showing promise with short-term symptom relief; however, the longevity of this treatment modality needs further study.[73][86]