SAN FRANCISCO, California—Radial extracorporeal shock wave therapy (rESWT) effectively relieved chronic plantar heel pain in a placebo-controlled study reported at the 2008 AAOS meeting, but results from an animal study raised questions about the cartilage effects of high-energy ESWT.1,2

“The study showed high efficacy of rESWT in chronic plantar heel pain without relevant side effects.”—Ludger Gerdesmeyer, MD.
Researchers led by Ludger Gerdesmeyer, MD, of the department of endoprosthetics at St. Elisabeth Hospital in Kiel, Germany, reported significant, durable relief of heel pain following treatment with rESWT. “The study showed high efficacy of rESWT in chronic plantar heel pain without relevant side effects.” Dr. Gerdesmeyer and colleagues randomized 254 patients to rESWT or placebo. The researchers reported that visual analog scale pain at 12 months was reduced 84.8% in rESWT-treated patients versus 43.2% in placebo patients. Side effects included minor petechial bleeding, swelling, and discomfort during treatment.

However, an animal study reported by Susanne Wagner, MD, from the orthopaedics clinic at Ludwig-Maximilians University in Munchen, Germany, suggests that high-energy ESWT commonly used to treat calcifying tendonitis, epicondylitis humeri radialis, and avascular necrosis of the femoral head might not be entirely benign.

Dr. Wagner treated the right hip joint of 18 adult Sprague-Dawley rats with 1500-impulse EWST at 0.5 mJ/mm2 and found that although plain radiographs did not show any changes, immunohistochemistry (IHC) told a different story. At 10 weeks after treatment, some hips showed a loss of proteoglycan in the hyaline cartilage, and IHC staining for Tenascin-C showed a marked increase in regions around chondrocytes in all zones.

“Tenascin-C was found to be increased in hyaline cartilage of the femoral head at 1, 4, and 10 weeks after high energy ESWT. Tenascin-C, which is an anti-adhesion molecule found in tissues undergoing remodeling, has been shown to be increased in osteoarthritis. We conclude that high energy ESWT might cause degenerative effects on joint cartilage. The application of high energy shock waves to treat avascular necrosis of the femoral head should be reconsidered,” Dr. Wagner said.

References
1. Gerdesmeyer L, Weill LS, Stienstra JJ, et al. Radial shock wave therapy in chronic heel pain—a prospective, randomized, placebo-controlled trial. Presented at: AAOS 2008 meeting; March 7, 2008; San Francisco, Calif. Presentation 483.
2. Wagner S, Ernst J, Maier M, et al. Effect of high-energy shock waves on hip joint cartilage. Presented at: AAOS 2008 meeting; March 7, 2008; San Francisco, Calif.