Extracorporeal Shockwave Therapy (ESWT)

HISTORY OF EXTRACORPOREAL SHOCKWAVE THERAPY

Extracorporeal Shockwave Therapy (ESWT), also known as shockwave therapy, was initially introduced in 1982 for the treatment of urologic conditions. Its efficacy in managing urinary stones led to its rapid adoption as a primary, non-invasive, and successful approach. Subsequently, ESWT was explored in orthopedics, where it was found to be effective in loosening cement during total hip arthroplasty revisions. Animal studies from the 1980s demonstrated that ESWT could enhance the bone-cement interface, stimulate osteogenic response, and accelerate fracture healing. Although its benefits in fracture healing are well-documented, orthopedic research has predominantly focused on tendinopathies, fasciopathies, and soft tissue conditions in the upper and lower extremities.

PHYSIOLOGY OF ESWT

Shockwaves possess specific physical attributes such as nonlinearity, high peak pressure followed by low tensile amplitude, short rise time, and short duration (10ms). They are characterized by a single pulse, a broad frequency range (0-20 MHz), and a high-pressure amplitude (0-120 MPa).

These features result in both a positive and negative shockwave phase. The positive phase exerts direct mechanical forces, while the negative phase induces cavitation and gas bubbles that implode rapidly, creating a secondary shockwave.

Compared to ultrasound waves, shockwaves exhibit a peak pressure about 1000 times higher than that of ultrasound waves.

MECHANISM OF ACTION

Although the outcomes of ESWT therapy are uncertain, the suggested mechanisms of ESWT action involve encouraging neovascularization at the tendon-bone junction, triggering the growth of tenocytes and osteoprogenitor cells, enhancing the infiltration of leukocytes, and boosting the synthesis of growth factors and proteins to promote collagen synthesis and tissue restructuring.

INDICATIONS FOR SHOCKWAVE THERAPY

·       Shockwave therapy is primarily used in the treatment of common musculoskeletal conditions. These include:

·       Upper and lower extremity tendinopathies

·       Greater trochanteric pain syndrome

·       Medial tibial stress syndrome

·       Patellar tendinopathy

·       Plantar fasciopathy.

·       Adhesive capsulitis

·       Non-union of long bone fracture

·       Avascular necrosis of femoral head

·       Osteoarthritis of the knee

·    There is no standardized ESWT protocol for the treatment of musculoskeletal conditions.

CONTRAINDICATIONS TO ESWT IN PHYSIOTHERAPY

·       Pregnancy

·       Over major blood vessels and nerves

·       Pacemakers or other implanted devices

·       Open wounds

·       Joint replacements

·       Epiphysis

·       Blood clotting disorders including thrombosis

·       Infection

·       Cancerous tissues

·       A compromised mental status of the patient and/or the inability to cooperate.

DIFFERENCES BETWEEN ESWT AND THERAPEUTIC ULTRASOUND

·       Therapeutic ultrasound utilizes high frequency sound waves, while ESWT utilizes lower frequency waves.

·       Ultrasound may produce either thermal or non-thermal effects in tissues, while ESWT does not result in heating effects.

SIMILARITIES BETWEEN THERAPEUTIC ULTRASOUND AND ESWT

·       Both modalities employ acoustic waves to produce therapeutic benefits.

·       They both make use of a coupling medium to transmit sound waves to the tissues being treated.

·       They are both non-invasive forms of treatment.