Effectiveness of Ultrasound-Guided Extracorporeal Shock Wave Therapy for Calcific Tendinitis of the Shoulder: A Randomized Double-Blind Controlled Trial

Calcific tendinitis of the shoulder is a debilitating musculoskeletal condition that significantly impacts the working-age population, typically those between 30 and 60 years of age. Accounting for approximately 7- 17% of shoulder pain complaints, it is characterized by the pathological deposition of calcium hydroxyapatite crystals within the rotator cuff tendons, most notably the supraspinatus. The progression of the disease, particularly during the resorptive phase described in Uhthoff's cycle, is associated with a dramatic increase in intratendinous pressure and severe inflammatory pain, leading to substantial functional impairment and socioeconomic burden. While Extracorporeal Shock Wave Therapy (ESWT) is a well established non-invasive modality known to promote calcific resorption via cavitation effects and mechanotransduction-induced neovascularization, its clinical efficacy remains highly variable across current literature, with success rates ranging widely from 47% to 87%. This inconsistency is largely attributed to the limitations inherent in conventional "blind" or landmark-based targeting techniques. Given that calcific deposits are often small, deeply situated, or obscured by the acromion, palpation-guided targeting is frequently unreliable, resulting in suboptimal energy delivery to the pathology and potential collateral damage to surrounding healthy tissues. This one-year research project aims to evaluate the superior efficacy of "Real-time Ultrasound-Guided" ESWT compared to conventional methods. The investigators propose a prospective, randomized, double-blind, controlled trial (RCT) that will recruit 60 patients with confirmed calcific tendinitis. Participants will be stratified by Gärtner classification (Type I-III) to ensure balanced morphological distribution and then randomized into either an experimental group receiving Ultrasound-Guided Focused ESWT or a control group receiving Landmark-based/Sham ESWT. The study incorporates rigorous methodology, including a priori power analysis for sample size estimation, strict allocation concealment, and assessor blinding. Outcomes will be assessed at baseline, 4, and 12 weeks post-treatment. Primary outcomes include the Constant-Murley Score (CMS) and Visual Analog Scale (VAS), while secondary outcomes involve quantitative ultrasound analysis using ImageJ software to measure the reduction in calcific deposit volume and assess tendon integrity. The investigators hypothesize that the integration of realtime ultrasound guidance will significantly enhance therapeutic precision, leading to higher rates of calcific resorption and functional recovery. The findings are expected to provide high-level evidence to standardize ESWT protocols, thereby advancing the implementation of precision medicine in the field of physical and rehabilitation medicine.