Chapter 11. Extracorporeal Shockwave Therapy

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.

Therapeutic shock waves were first introduced into medicine over 20 years ago for the treatment of kidney stones. Shock waves have since become the primary treatment choice for urinary, biliary, and salivary calculi. More recently, extracorporeal shock wave therapy has been utilized to treat musculoskeletal conditions such as lateral epicondylitis and plantar fasciitis in the United States33 (Figure 11–1).

This is especially important in the 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 shown to be effective in stimulating growth of these collagen building cells.2,3 Furthermore, other musculoskeletal disorders have been treated in Europe including; pseudoarthrosis, nonunion fractures, and during total joint revisions. There have been a number of prospective trials examining the effects of ESWT in the last 10 years with mixed results. The disparity in results suggest there is a need define more accurate indications to optimize therapeutic outcomes.4 This chapter will clarify the terminology and principles of shock wave therapy, discuss the potential biologic effects of shock waves, 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. Current recommendations 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 process. We explore ESWT and its potential benefits in musculoskeletal rehabilitation.

To understand the potential biologic effects of the mechanical energy of shock waves, it is helpful to understand their physical properties. A shock wave is a sonic pulse that is characterized by the following physical parameters: a high peak pressure (sometimes as high as 100 MPa but usually around 50–80 MPa), a fast initial rise in pressure (less than ...