Efficacy of extracorporal shock-wave treatment for calcific tendinitis of the shoulder: experimental and clinical results.

The effects of various extracorporal shock wave energy levels and impulse rates were investigated using an in vitro model. In addition, we performed a controlled, randomized study to examine the clinical outcome after treatment for calcific tendinitis of the shoulder. Two groups of 40 patients each received 2000 impulses twice with an energy flux density of 0.23 mJ/mm(2) and then 0.42 mJ/mm(2). The results were evaluated by the Constant and Murley score. Disintegration of the implanted deposits requires an energy of at least 0.42 mJ/mm(2) and 2000 impulses. The clinical trial showed resorption of calcific deposits in 37.5% (0.23 mJ/mm(2)) and 55.0% (0.42 mJ/mm(2)). After 1 year the Constant and Murley score increased from 46 to 68 at 0.23 mJ/mm(2) and from 48 to 73 points at 0.42 mJ/mm(2). Based on our experimental and clinical results it is evident that disintegration of calcific deposits is dose-dependent. Because of the time that elapses until changes became evident on the radiographs, an instant and sole mechanical effect on the calcific deposits is unlikely. Therefore, a combined mechanical and cellular mechanism for absorption of the calcific deposits must be presumed.