2 The procedure
2.1.1 Plantar fasciitis is characterised by chronic degeneration of the plantar fascia, which causes pain on the underside of the heel. It is usually caused by injury or biomechanical abnormalities and may be associated with microtears, inflammation or fibrosis.
2.1.2 Conservative treatments include rest, application of ice, analgesic medication, non-steroidal anti-inflammatory drugs, orthotic devices, physiotherapy, eccentric training/stretching and corticosteroid injection.
2.2.1 Extracorporeal shockwave therapy is a non-invasive treatment in which a device is used to pass acoustic shockwaves through the skin to the affected area. Ultrasound guidance can be used to assist with positioning of the device.
2.2.2 Extracorporeal shockwave therapy may be applied in one or several sessions. Local anaesthesia may be used because high-energy ESWT can be painful. Different energies can be used and there is evidence that local anaesthesia may influence the outcome of ESWT.
2.2.3 The mechanism by which this therapy might have an effect on tendinopathy is unknown.
Sections 2.3 and 2.4 describe efficacy and safety outcomes from the published literature that the Committee considered as part of the evidence about this procedure. For more detailed information on the evidence, see the overview.
2.3.1 A randomised controlled trial (RCT) of 293 patients treated by ESWT or sham ESWT reported that 47% (67/144) and 30% (42/141) of patients, respectively, had 'successful' outcomes at 3-month follow-up (defined as at least 50% reduction in pressure-induced pain and pain during walking, at least a 1-point reduction in pain score on a 5-point visual analogue scale [VAS] [higher scores indicate greater pain] and no requirement for pain medication 10–12 weeks after treatment) (p = 0.008).
2.3.2 In an RCT of 172 patients treated by ESWT or sham ESWT, the mean reduction in pain score (assessed by a 5-point VAS) from baseline to 3-month follow-up was 3.4 in the ESWT group (n = 112) compared with 1.8 in the sham ESWT group (n = 56) (p < 0.001).
2.3.3 An RCT of 149 patients treated by ESWT or conservative management reported that 69% of ESWT patients and no patients treated conservatively had an 'excellent' result (no heel pain) and 14% and 55% of each group, respectively, had a 'good' result (50% or greater reduction in baseline pain) at a mean follow-up of 64 months.
2.3.4 The Specialist Advisers stated that the key efficacy outcome was relief of symptoms.
2.4.1 The RCTs of 272 and 166 patients reported pain during treatment in 5% (7/135) and 1% (1/81) of ESWT patients, and 1% (2/136) and 1% (1/85) of sham patients, respectively. The RCT of 125 patients reported throbbing pain and erythema requiring ice in 10% (6/61) of ESWT patients, compared with pain requiring analgesia or ice for a mean duration of 7 days in 13% (8/64) of patients who had a single corticosteroid injection.
2.4.2 The RCT of 272 patients reported that 12% (16/135) of ESWT patients and 4% (5/136) of sham ESWT patients had skin reddening. In the RCTs of 272 and 172 patients, 2% (3/135) of ESWT patients and 1 ESWT patient, respectively, had local swelling.
2.4.3 The Specialist Advisers listed adverse events as bruising, pain and local skin damage. They considered theoretical adverse events to include exacerbation of the condition because of rupture of the plantar fascia or local soft tissue damage.
2.5.1 The Committee found interpretation of the data difficult because of the diversity of treatment protocols and comparators used, varying reported end points, and inconsistencies in terms of the use of local anaesthesia and energy type. The results of studies conflicted and there was evidence of a substantial placebo response. Previous guidance on this procedure published in 2005 had found the evidence on efficacy inadequate, and new evidence has not been published to alter that view.
2.5.2 Plantar fasciitis is a common condition and many patients who have it are refractory to other treatments. If the procedure is efficacious in selected patients, it has the potential for a high impact. This makes provision of robust data particularly important.