The purpose of the present study is the evaluation of a possible influence of the preoperative deposit stage, the postoperative deposit elimination and failed preoperative extracorporeal shockwave therapy on the surgical outcome of arthroscopic treatment of tendinosis calcarea. From 1997 to 2004, 65 patients underwent arthroscopic resection of calcific deposits of the shoulder after failed conservative treatment. Patients with rotator cuff tears, major cartilage damage, or previous surgery were excluded. Out of 50 patients 45 (17 men, 28 women) that could be contacted with a mean age of 49 +/- 8 years could be followed-up with a mean of 36 months (14-89) after surgery. A total of 24 patients (53.3%) underwent preoperative extracorporeal shock-wave therapy (ESWT). For the clinical evaluation the Constant and Murley Score, the Simple Shoulder Test, the Western Ontario Rotator Cuff Index (WORC) and visual analog scales for pain, function and satisfaction were used. For the radiological evaluation, the classifications according to Gaertner and Bosworth were used. Statistical analysis was done with the Wilcoxon test, the Mann-Whitney test and ANOVA. The Constant and Murley Score improved significantly from preoperative 63.5 +/- 11.4 to postoperative 93.9 +/- 9.9 points (P < .0001) at follow-up, the Simple Shoulder Test from 1.7 +/- 2 to 9.9 +/- 2.8 points (P < .0001), the WORC score from 1,591.2 +/- 337.4 to 345.4 +/- 392 points (P < .0001). The visual analog scales for pain, function and patient satisfaction also significantly improved (P < .0001). Preoperative radiological evaluation according to the Gaertner classification revealed 37 type I deposits, 6 type II and 2 type III deposits; postoperative no calcific deposits were seen in 37 patients, 6 type I and 2 type III deposits. According to the Bosworth classification 13 type I, 19 type II and 13 type III deposits were seen preoperatively. Postoperative X-rays showed 6 type I and 1 type II and III deposits. There was no significant correlation of the clinical results with the pre- or postoperative findings. The 24 patients who underwent ESWT before surgery did not show significantly better results than patients without ESWT. In conclusion, arthroscopic removal of calcific deposits of the shoulder shows good clinical results for pain reduction, shoulder function and patient satisfaction. The type of calcific deposit and the preoperative treatment of the shoulder with ESWT did not have any significant impact on the postoperative results.