Chapter 11: Extracorporeal Shockwave Therapy

OBJECTIVES

Following completion of this chapter, the student will be able to:

• Describe the mechanical characteristics of extracorporeal shockwaves.

• Identify musculoskeletal pathologies that may benefit from extracorporeal shockwave therapy.

• Discuss the cellular effects of extracorporeal shockwave therapy on bone and tendons.

• Discuss why these effects may be beneficial to these tissues.

HISTORY OF EXTRACORPOREAL SHOCKWAVE THERAPY (ESWT)

Therapeutic shock waves were first introduced into orthopedic medicine over the last 20 years for the treatment of a variety of conditions. Extracorporeal shockwave therapy has been utilized to treat conditions such as lateral epicondylitis, plantar fasciitis and rotator cuff, patellar, and achilles tendinopathies in the United States³³ (Figure 11–1).

This approach appears effective in particular for treatment of patients with chronic tendinopathies that are difficult to treat. It is becoming clear that “chronic inflammation” is not present and regeneration of tendocytes is needed to facilitate healing.¹ The biologic effects of ESWT have been shown to stimulate growth factors and stem cells to foster new collagen.^2,3,57 ESWT also seems to have a significant effect on pain for treatments of other musculoskeletal disorders including pseudoarthrosis, nonunion fractures, and during total joint revisions. Emerging literature suggests that ESWT is effective when compared to placebo injections, and augmented by eccentric exercise in the treatment of chronic tendinopathies.⁴ This chapter will clarify the terminology and principles of shockwave therapy, discuss the potential biologic effects of shockwaves, and review the current use of ESWT in the treatment of musculoskeletal conditions. Finally, evidence-based clinical guidelines for use of ESWT will be presented.

ESWT will continue to be used more especially in the treatment what has traditionally been referred to as chronic tendonitis. It is important to discuss this topic briefly before we begin. Traditionally, physical therapists, athletic trainers, and physicians have concluded that longstanding symptoms of tendonitis were the result of the healing process being “stuck” in the inflammatory phase. However it is becoming clear that this is not the mechanism underlying this chronic condition. Patients who clearly have chronic tendinosis or fasciosis on a clinical basis (i.e., duration of at least six months and failure of other conservative measures, especially NSAIDS and/or steroid injection) seem to respond best to ESWT. Observations that those who respond best have failed steroid injection and other conservative therapies likely indicate a better selection of those patients who have no inflammatory component to their condition.^54–56 Current recommendations for treatment include a period of rest, followed by aggressive eccentric exercise to stimulate tendon regeneration.^1–3,5–9 ESWT's demonstrated biologic effects of decreasing pain and promoting tissue regeneration make it an ideal adjunct to the rehabilitation ...