Calcifying Tendonitis of the Shoulder: Risk Factors and Effectiveness of Acetic Acid Iontophoresis and Ultrasound

To clinically characterize calcifying tendonitis of the shoulder (CT) through a prospective quasi-experimental before-and-after study, which provides a level of demonstrable evidence to support the decision-making and demonstrate the effectiveness of acetic acid iontophoresis and ultrasound in the treatment of CT.

Prospective, quasi-experimental before-after intervention study was conducted on 44 patients who referred to the rehabilitation department, Santísima Trinidad’s General Foundation hospital, Salamanca, from June 2014 to April 2016. Outcome measures: 1) Pain: measured by visual analogical scale (VAS); 2) calcification size: in millimetres, both measured radiologically at the beginning/end of treatment; 3) Intervention: Iontophoresis with 5% acetic acid at 4.7 mA × 10 minutes and continuous ultrasound 1 W/cm2 /1 MHz × 5 minutes over calcification.

Mean age of the subjects was 54.2 years (n = 44), 65.9% female (n = 29), (95% with supraspinatus tendon (n = 38) and 5% with subscapularis (n = 2); 55% had complication in left shoulder (n = 22), 45% in right shoulder (n = 18) and 4.5% bilateral (n = 2). Regarding the occupation, 59.1% had (n = 26) administrative positions and 40.9% manual jobs (n = 18). On personal history: 34.09% were smoker (n = 15), 4.5% had diabetes (n = 2) and calcium intake secondary to osteoporosis was recorded for 2.27% (n = 1) of the subjects. Regarding radiological type: 68.18% formative (n = 30), 38.72% resorptive (n = 14) were observed. Average number of sessions was 19 and 9.01% (n = 4) of the subjects had treatment complications as intolerance/erythema/burn. Average initial pain was 7.7 points (VAS scale), significantly decreased (P = 0.0000) post treatment to 2.2. Initial average size of calcification was 10 mm and significantly decreased (P = 0.0000) post treatment to 3 mm. With respect to the change of calcification: success/cure rate was 56.8% (n = 25), improvement rate was 25% (n = 11); failure rate was 18.2% (n = 8).

CT is common in middle-aged working females. It affects supraspinatus tendon. It is associated with smoking. Occupational risk factors are awkward positions and lifting weights. Iontophoresis with 5% acetic acid and ultrasound is a safe, simple and inexpensive technique, capable to reduce pain and calcification, with a recommended degree of scientific evidence (2B).