Extracorporeal Shockwave Therapy (ESWT) otherwise referred to as shockwave therapy, was first introduced into clinical practice in 1982 for the management of urologic conditions. The success of this technology for the treatment of urinary stones quickly made it a first-line, noninvasive, and effective method. Subsequently, ESWT was studied in orthopedics where it was identified that it could loosen the cement in total hip arthroplasty revisions. Further, animal studies conducted in the 1980s revealed that ESWT could augment the bone-cement interface, enhance osteogenic response and improve fracture healing. While shockwave therapy has been shown to be beneficial in fracture healing, most orthopedic research has focused on upper and lower extremity tendinopathies, fasciopathies, and soft tissue conditions.
Shockwaves are sound waves that have specific physical characteristics, including nonlinearity, high peak pressure followed by low tensile amplitude, short rise time, and short duration (10 ms). They have a single pulse, a wide frequency range (0-20 MHz), and a high pressure amplitude (0-120 MPa) These characteristics produce a positive and negative phase of shockwave. The positive phase produces direct mechanical forces, whereas the negative phase generates cavitation and gas bubbles that subsequently implode at high speeds, generating a second wave of shockwaves. In comparison to ultrasound waves, the shockwave peak pressure is approximately 1000 times greater than the peak pressure of an ultrasound wave.
