Needle aspiration of calcific deposits versus shock wave therapy for conservative therapy resistant calcifying tendinitis of the shoulder: protocol of a randomized, controlled trial

BACKGROUND: Calcific tendinitis of the shoulder (CT) is a common disorder with a large disease burden. The initial treatment is with conservative measures. However, when this fails the next step treatment remains unclear. Minimal invasive treatment modalities have emerged. Needle aspiration of the calcific deposits (NACD) and extracorporeal shock wave therapy (ESWT) have both shown good clinical results. Nonetheless, in the current orthopedic literature there are not any studies available that compare both the effectiveness and cost-effectiveness of those two treatment modalities. Therefore, our primary objective is to compare the effectiveness of NACD to ESWT. A secondary objective is to compare the cost-effectiveness of both treatment modalities and workability. METHODS: Following a power calculation using the minimal clinical important difference of our primary outcome (Constant-Murley score, CMS) 140 patients will be included in the study. Enrolment is based upon strict inclusion/ exclusion criteria outlined in the Methods section. Participants will be randomized by computer in two groups (e.g. 70 patients will receive NACD and 70 patients will receive ESWT). The NACD treatment will consist of a sonographically guided removal of the calcific deposits and the ESWT treatment will be a focused ESWT. Both treatments will be conducted according to a standardized protocol, as part of care as usual in our hospital. The primary outcome will be the between group differences in functional outcome (measured with the CMS) between baseline and after 12 months follow-up. Secondary outcomes will be questionnaires regarding the clinical outcome (SST) and quality of life (EQ-5D-5L). Furthermore, NRS pain and cost related questionnaires (iPCQ and ProDisQ) will be collected during follow-up after two months, six months and at final follow-up after 12 months. DISCUSSION: This study will provide more insight regarding treatment for conservative therapy resistant calcific tendinitis of the shoulder by comparing NACD to focused ESWT, which will aid the physician and patient in determining the appropriate treatment plan. TRIAL REGISTRATION: Dutch trial register: NTR7093 registered on 11 March 2018.