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Plantar fasciitis, a special type of a soft tissue rheumatic syndrome, is a common painful condition which often becomes chronic. Its aetiopathology is not completely understood.1 Being over weight and standing work are regarded as predisposing factors.2 Microtrauma, nerve entrapment (Baxter’s nerve), or limited ankle dorsiflexion are thought to be responsible.3,4
Most patients can be treated with physical therapy, local glucocorticoid injections, insoles, acupuncture, and extracorporeal shock wave therapy.5,6 However, this treatment cannot improve the pain in all cases and can require a lot of time on the part of both patient and therapist. Surgery is controversial and should be restricted to patients who do not respond to conservative treatment.
It is not yet clear whether treatment of chronic plantar fasciitis with botulinum toxin A (Btx-A) works by causing muscle paresis or by analgesic/anti-inflammatory effects, or both. A combined effect may occur—namely, (a) induction of paresis of the muscles originating at the medial calcaneal process and (b) occurrence of direct analgesia owing to its anti-nociceptive and anti-inflammatory properties.7,8,9,10
In this pilot study here the effect of a single injection of Btx-A was studied in an open case series.
Nine patients with chronic plantar fasciitis (five women, four men, mean (SD) age 55 (9.5) years) were treated with Btx-A. The average disease period was 14 months (range 2–36). Patients were selected according to the inclusion and exclusion criteria of an already planned multicentre study (table 1).
Btx-A (500 units; Dysport, IPSEN Pharma, Ettlingen, Germany) was dissolved in 5.0 ml injection solution (0.9% saline), and 2.0 ml (200 units) were injected subfascially in four different directions through one injection puncture into the painful area at the origin of the plantar fascia. The procedure was always performed by the first author.
The following measurements were recorded at weeks 2, 6, 10, 14, 26, 39, and 52:
Greatest pain during the past 48 hours using a visual analogue scale (VAS), 0–10
Pain at rest during the past 48 hours using a VAS, 0–10
Measurement of muscle force using Brunner’s method, scale 0–5, for
Extension and flexion of the great toe
Extension and flexion of the foot
Pronation and supination of the foot
Pain progression stage using Gerbershagen’s score (Mainz Pain Staging System) at first visit (injection) and final examination (week 52).
Statistical analysis was performed using Wilcoxon’s test.
Two weeks after injection a pronounced and statistically significant reduction of pain at rest during the past 48 hours was observed using a VAS (fig 1). The maximum pain during the past 48 hours was reduced to the same extent (p<0.015).
The recorded Mainz Pain Staging System (1–3) at injection and at week 52 showed a decrease from an average stage of 1.56 to 1.00. It is certainly not a specific tool for staging chronicity in plantar fasciitis, but we aimed at making a general statement on the course of the disease. Undesirable effects such as muscle weakness or systemic reactions were not seen. Our patients were satisfied not only by the pain relief but also that only one injection was needed. The treatment is cost effective compared with repeated physical treatment, acupuncture, or extracorporeal shock wave therapy.
Our results thus suggest that a single injection of 200 units Btx-A (Dysport) may be a possible treatment for patients with chronic plantar fasciitis. This level IV study may yield the database for a power analysis of a double blind, placebo controlled multicentre study (in preparation).
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