Research Review By Dr. Shawn Thistle©

Date Posted:

Dec. 2008

Study Title:

Radial extracorporeal shock wave therapy is safe and effective in the treatment of chronic recalcitrant plantar Fasciitis
Results of a confirmatory randomized placebo-controlled multicenter study

Authors:

Gerdesmeyer L et al.

Author's Affiliations:

Technical University Munich, Germany; Mare Clinic, Germany; Orthopedic Foot and Ankle Center, California, USA; Ludwig Maximilian University, Germany; Weil Foot and Ankle Clinic, Illinois, USA; The Permanente Medical Group Inc., California, USA; University Rostock, Germany; Institute of Sportsmedicine, Frankfurt, Germany

Publication Information:

American Journal of Sports Medicine 2008; 36(11): 2100-2109.

Background Information:

Plantar Fasciitis (PF) is one of the most common foot conditions seen in manual medicine practice. Current epidemiological data on PF suggests that it afflicts up to 10% of the adult population over the course of a lifetime, and accounts for 15% of all foot complaints requiring professional care. Although this condition is typically self-limiting, there are a small percentage of patients that enter a recalcitrant state of chronic heel pain despite manual and medical intervention. These patients often undergo surgery, which is associated with prolonged recovery periods and other obvious drawbacks.

Radial Extracorporeal Shock Wave Therapy (rESWT) represents an alternative to focused (or traditional) shockwave treatment, allowing for a broader application of the therapeutic stimulus. rESWT generates shock waves by accelerating a bullet which hits the applicator, transforming its kinetic energy into radially expanding shockwaves. Focused ESWT administers a more precise energy which allows deeper tissue penetration, but with significantly higher energy focused into a smaller area.

The literature to date examining ESWT for PF has been contradictory, likely due to differences in treatment parameters including: device settings, use of local anesthesia (which tends to reduce efficacy), and location of treatment application (this study utilized point of maximal tenderness which makes more intuitive sense). What has been established is that higher energy applications are generally associated with better outcomes (1, 2, 3).

This study was a randomized, controlled, and double-blinded Food and Drug Administration (FDA) study evaluating the efficacy of rESWT for treatment of recalcitrant PF.

Pertinent Results:

  • 252 patients were randomized to receive either rESWT (n=129) or placebo rESWT (n=123) – the two groups were similar in terms of demographics and baseline intensity/duration of heel pain
  • the VAS composite score (heel pain with first steps in the morning, heel pain with daily activities, and heel pain while applying standardized local pressure [with a Dolormeter – EMS Electrical Systems]) was significantly lower at 12 weeks in the rESWT group (reduction of 72% versus only 44.7% in the placebo group [p = 0.022])
  • the overall success rate of rESWT was 61% at 12 weeks compared to 42.2% in the placebo group (p = 0.002)
  • at 12 months, the superiority of rESWT in all outcomes was more pronounced (p < 0.25) - the composite VAS score was reduced 84.8% in the rESWT group versus 43.2% in the placebo group
  • there were 50 device-related adverse events (46 of which were non-severe) – discomfort was not reported past 10 minutes, and no patient requested local anesthetic
  • 93.8% of rESWT patients rated tolerability of the treatment as “very good” or “good”

Clinical Application & Conclusions:

PF is a common condition that can become disabling when it does not respond to front line manual or medical treatments. This study provides evidence that rESWT is a reasonable treatment option for those with recalcitrant PF. This study applied 3 consecutive rESWT treatments about 2 weeks apart (3 x 2000 impulses, 0.16mJ/mm2). When incorporating the results of this study into practice, it should be remembered that the ESWT applied in this study was radial, which is a bit different than “focused” ESWT – check your device to clarify the settings and capabilities. Further, the results of this study can only be applied to those with chronic recalcitrant PF.

To date, there is no convincing evidence that rESWT is more efficacious than other manual or medical treatments in the early stages of this condition.

Study Methods:

This study was conducted internationally at three major centers in the USA and 5 in Europe. A total of 254 patients (average age ~52) from all activity levels were enrolled from referring family physicians. To be included, patients had to have:
    at least 6 months of chronic plantar heel pain (on average, patients has over 2 years of symptoms) confirmed on physical examination by maximal tenderness on the medial tubercle of the calcaneus
  • minimum score of at least 5 (50%) or greater on 3 VAS scales (heel pain with first steps in the morning, heel pain with daily activities, and heel pain while applying standardized local pressure [with a Dolormeter – EMS Electrical Systems])
  • significant limitation on the Roles and Maudsley Score
  • failed results on at least 2 pharmacological AND 2 non-pharmacological treatments
  • a sufficient washout period from previous treatments
Patients were excluded if they had rheumatic or other systemic conditions, osteomyelitis, active infection or history of chronic infection, nerve entrapment syndrome (see related review below), coagulatory problems or undergoing anticoagulatory therapy, significant bilateral heel pain requiring medical care, or pregnancy.

Patients randomized to receive rESWT received treatment in 3 sessions, each about 2 weeks apart. During these sessions, 2000 shockwaves were delivered with a Swiss Dolocast Radial Shockwave device (EMS Electro Medical Systems, Switzerland). The treatment was applied at the point of maximal tenderness with an energy flux density of 0.16mJ/mm2 and a rate of 8 impulses per second.

Patients in the placebo group received treatment with an identical looking device utilizing the same setup and producing the same sound as the real unit.

Standardized rescue medication was allowed throughout the study if the pain became unbearable (2g of acetaminophen/day). No other treatments were permitted, including the prescription of foot orthotics.

Outcome measures were recorded at baseline, 12 weeks, and 12 months. Success of treatment was defined as a minimum reduction of 60% on at least 2 of 3 VAS scales. At 12 weeks, those who were still in significant pain were allowed to pursue other treatments.

Study Strengths / Weaknesses:

This study’s main strength is its patient sample – restricted to those with recalcitrant plantar fasciitis that had not responded to previous treatments. This is a difficult group to treat, and this study provides evidence that rESWT may be a viable alternative for these patients before they explore more invasive treatments such as surgery. Further, the sample size was more than sufficient to provide statistical strength to the results. The outcome measures were appropriate, and the follow-up times were adequate to demonstrate the prolonged benefits of the treatment.

Additional References:

  1. Malay DS et al. Extracorporeal shockwave therapy versus placebo for the treatment of chronic proximal plantar fasciitis: results of a randomized, placebo-controlled, double-blinded multicenter, intervention trial. Journal of Foot and Ankle Surgery 2006; 45: 196-210.
  2. Ogden JA. Extracorpoeal shockwave therapy for plantar fasciitis: randomized, controlled, multicenter trial. British Journal of Sports Medicine 2004; 38: 382.
  3. Theodore GH et al. Extracorporeal shockwave therapy for the treatment of plantar fasciitis. Foot & Ankle International 2004; 25: 290-297.