The Therapeutic Effect of the Extracorporeal Shock Wave Therapy on Shoulder Calcific Tendinitis

Calcific tendinopathy of the shoulder is caused by unknown etiology characterized by the formation of calcific deposits in on or several tendons of the rotator cuff muscles: supraspinatus, infraspinatus, teres minor, and subscapularis muscles. The calcific deposits is often composed of poorly crystallized hydroxyapatite, an inorganic component of bone tissue, but the pathogenesis of rotator cuff disorders is still incomplete. The clinical presentations of calcific tendinopathy typically involve shoulder pain similar to that experienced by patients with rotator cuff tendinopathy or shoulder impingement syndrome. Pain is the cardinal symptom and is localized on the top or lateral aspect of the shoulder or both, often with radiation towards the insertion of the deltoid. The onset of pain is gradual and unassociated with trauma. Daily activities involving overhead motions, such as putting on a shirt or brushing hair, can be painful, thus decreasing quality of life immensely. Calcific tendinopathy of the shoulder is often self-limited with a relatively benign clinical course. Therefore, first-line therapy should be conservative and focused on symptom relief. However, some remain ineffective to the initial treatment. For those refractory cases, extracorporeal shock wave therapy (ESWT) is introduced and shows resolution of symptoms and improvement in shoulder function in approximately 70 percent of patients. ESWT uses acoustic waves to fragment calcific deposits. Variables of the settings include dose (low or high energy), duration (impulses), and the interval of administration. However, an optimum value for the total cumulative dose of energy that should be administered has not yet been defined. Our study thus aim to find out the dosage effect of ESWT on the calcific debris sizes, pain, daily living functions, and shoulder range of motions in the calcific tendinitis patients. The study will be a prospective assessor-blinded randomized controlled trial. Patients who have calcific tendinitis diagnosed by shoulder sonography or X-ray, fail to improve despite appropriate conservative treatment for three months will be recruited. The subjects will be randomized distributed in 3 groups: High Energy, Low Energy, and Sham groups, and each group has 30 patients. Upon completion of the study, the result will show whether different dosage of ESWT has different therapeutic effects on shoulder calcific tendinitis. In the future, the study may be the foundation of the ESWT treatment guideline for rotator calcific tendinitis.