The Role of Body Mass Index in Outcomes of Radial Shock Wave Therapy for Adhesive Capsulitis

Background: Radial shock wave therapy (RSWT) has increasingly been integrated into treatment protocols for adhesive capsulitis. While associations with diabetes and other systemic disorders are well documented, the role of obesity remains underexplored, particularly in relation to RSWT outcomes. Methods: Forty patients with adhesive capsulitis completed a 10-day treatment protocol combining RSWT with conventional physiotherapy. Pain (VAS), disability (SPADI), and range of motion (ROM) were assessed at baseline and immediately after treatment. At one-month follow-up, VAS and SPADI were reassessed alongside the Patient Global Impression of Change (PGIC). Correlations between body mass index (BMI) and clinical outcomes were analyzed, and potential confounding effects of comorbidities and affected-side dominance were examined. Clinical relevance was assessed using minimal clinically important differences (MCID) and effect sizes (Cohen's d). Results: All clinical outcomes improved significantly post-treatment and at follow-up, with most changes exceeding MCID thresholds and showing large effect sizes. Higher BMI was significantly correlated with greater improvements in SPADI, VAS, shoulder extension, and internal rotation. Most comorbidities were negatively associated with outcomes, except neurologic conditions, which supported mobility improvement. Conclusions: RSWT appears effective in alleviating symptoms of adhesive capsulitis. The observed association between higher BMI and greater mobility improvement suggests potential benefits in overweight and obese patients. These findings warrant further investigation.