The Scientific Weeds of the Focused Shockwave 2003 JAMA RCT on Calcific Shoulder Tendinopathy

A landmark randomized controlled trial on focused shockwave therapy was published in 2003 in JAMA, one of the highest impact journals in the medical field. The improvements for shoulder calcific tendinopathy in this study  include:

• Reduction in pain levels
• Improved function using the Constant-Murley Score  (A 100-point scale used to measure overall shoulder function and track recovery after an injury or treatment)
• Long term reduction in shoulder tendon calcium deposits, demonstrated on X-ray months after treatment ended

These beneficial outcomes mirror what has been demonstrated in subsequent research on focused shockwave in the last 20 years, and from clinical reports on patient outcomes.

Key Points From the Article

Shoulder pain due to calcific tendonitis is a common problem, for which conservative therapy is sometimes ineffective. In these cases, ESWT has been proposed as an alternative to operative procedures, although methodological flaws have limited the conclusions of previous studies. In our study, we found a significant clinical benefit for both high- and low-energy ESWT at 6 months, with significantly better outcomes associated with high-energy ESWT.

We compared the effectiveness of high-energy and low-energy ESWT vs placebo (ie, sham treatment) in patients with chronic, symptomatic calcific tendonitis of the supraspinatus tendon.

Either high-energy ESWT, low-energy ESWT, or placebo (sham treatment). The 2 ESWT groups received the same cumulative energy dose.

Participants were eligible if they were aged 18 years or older, had calcific deposits of 5 mm in diameter or larger on radiography, and had had symptoms for at least 6 months. Rotator cuff tears and subacromial bursitis were ruled out in all patients by clinical and sonographic examination, and when in doubt, by magnetic resonance imaging prior to randomization and at all follow-up visits.

All patients had had at least a 1-month, therapy-free period before the first treatment with ESWT.

This randomized controlled trial is compelling for two reasons:

1. Functional shoulder outcome scores were over 4x greater in the high energy focused shockwave group: 31 points  improvement versus  6.6 points in the sham treated group on the Constant–Murley scale.
2. Follow up X-rays in the high energy shockwave group demonstrated reduction in calcium deposits in the shoulder at 6 months and 12 months after treatment, indicating that shoulder tendon healing continued for months after treatment ended. 

This mirrors what we see clinically, which is improvements pain levels and joint function at the start of shockwave treatment, and improvement over time (weeks and months) after focused shockwave treatment has ended.

Reference:

Gerdesmeyer L, Wagenpfeil S, Haake M, et al. Extracorporeal Shock Wave Therapy for the Treatment of Chronic Calcifying Tendonitis of the Rotator Cuff: A Randomized Controlled Trial. JAMA. 2003;290(19):2573–2580. doi:10.1001/jama.290.19.2573