Interventional procedure overview of extracorporeal shockwave therapy for calcific tendinopathy in the shoulder

Indications and current treatment

Calcific tendinopathy (also known as calcific tendonitis) is a disorder of the shoulder characterised by the formation of deposits of calcium crystals in 1 or more of the rotator cuff tendons. It can cause symptoms such as pain in the upper arm and shoulder, reduced range of movement, stiffness and weakness. The exact cause is unknown.

Most cases of calcific tendinopathy resolve in time without treatment. In the early stages, symptom management includes painkillers and anti-inflammatory medication. If symptoms persist, physiotherapy may be needed. Other treatment options include steroid injection, percutaneous lavage or barbotage (using a needle to suck up or break up the calcium deposits), or surgery.

What the procedure involves

Extracorporeal shockwave therapy (ESWT) is a non-invasive treatment in which a device is used to pass controlled, short-duration acoustic shockwaves through the skin to the affected area. This produces transient pressure disturbances, which break up calcium deposits. There are 2 different types of ESWT. In focused ESWT the energy generated converges at a selected depth in the body tissues where the maximal pressure is reached. In radial ESWT the maximal pressure is at the skin surface and then diverges as it penetrates deeper.

Local anaesthesia is sometimes used for pain relief during the procedure and ultrasound guidance can be used to assist with positioning the device.

Treatment protocols for ESWT vary according to the energy density and frequency of shockwaves.

The mechanism by which this therapy might have an effect on tendinopathy is unknown. The aim is to reduce pain and improve function.

Outcome measures

Shoulder Pain and Disability Index (SPADI)

The SPADI is a self-completed questionnaire with 13 items assessing pain level and extent of difficulty with activities of daily living that use the upper extremities. The pain subscale has 5 items and the disability subscale has 8 items. The patient chooses the number that best describes their level of pain and extent of difficulty using the involved shoulder. The total SPADI score is expressed as a percentage between 0 and 100. A higher score means more pain and disability.

Constant-Murley score (CMS)

The CMS is a 100-point scale that measures the level of pain and the ability to do activities of daily living. The test is divided into 4 subscales: pain (15 points; 0 is maximal pain and 15 is no pain), activities of daily living (20 points; higher scores better), strength (25 points; 1 point per 0.5 kg) and range of motion: forward elevation, external rotation, abduction and internal rotation of the shoulder (40 points; higher scores better). A higher score means less pain and better function.

Disabilities of the Arm, Shoulder and Hand (DASH)

The DASH questionnaire is a 30-item questionnaire that measures the ability to do certain upper extremity activities. It is a self-completed questionnaire that rates difficulty and interference with daily life on a 5 point Likert scale. The score ranges from 0 to 100 and higher scores indicate a greater level of disability and severity.