Comment on: Focal extracorporeal shockwave therapy in shoulder calcific tendinopathy: A retrospective observational study of sonographic prognostic factors

Editor,

I read with keen interest the article by Pesaresi et al., “Focal extracorporeal shockwave therapy in shoulder calcific tendinopathy: A retrospective observational study of sonographic prognostic factors,” published in PM&R. ¹ The authors are to be sincerely commended for addressing a clinically significant and often challenging condition, where treatment outcomes remain unpredictable and reliable prognostic indicators are lacking. By examining ultrasonographic features as potential predictors of therapeutic response, this study provides valuable insights that bridge imaging and clinical practice, thereby enhancing decision‐making in the management of calcific tendinopathy. The thoughtful use of structured sonographic parameters and functional outcome measures demonstrates methodological care and adds weight to their findings. This work undoubtedly enriches the current discourse on shoulder rehabilitation and offers promising avenues for future research. However, despite its merits, the study presents several important limitations that warrant closer examination.

First, the study does not adjust for demographic influences such as body mass index, diabetes, or smoking status. These factors are known to significantly affect healing response and overall treatment outcomes. Without accounting for such demographic variability, there is a risk of biased interpretations regarding treatment effectiveness. For instance, Vertuccio et al. ² demonstrated that demographic characteristics significantly influenced therapeutic outcomes. Second, the absence of Doppler ultrasound limits assessment of vascular changes, which are central to inflammation, tissue repair, and long‐term healing. Vascularity influences fibroblast activity, collagen remodeling, and pain modulation; without measuring it, the study may underestimate treatment effects or overlook patients with poor vascular adaptability who respond less favorably. Santamato et al. ³ showed that Doppler imaging can capture such vascular changes after shockwave therapy, highlighting its importance in evaluating therapeutic mechanisms. Third, the reliance on self‐reported outcome measures such as Disabilities of the Arm, Shoulder and Hand, Shoulder Pain and Disability Index, and Numeric Rating Scale, without adjustment for potential confounders, represents a significant methodological limitation. These instruments are inherently subjective, being influenced by recall bias, psychosocial context, and variability in pain perception. Furthermore, heterogeneity in follow‐up intervals introduces inconsistency in data acquisition, raising the risk of attrition bias and diminishing the robustness of longitudinal findings. Korakakis et al. ⁴ emphasized in a systematic review that methodological weaknesses arising from subjective reporting and nonuniform follow‐up schedules compromise the validity of outcome assessments and reduce the strength of clinical inferences. Fourth, the study provides limited detail regarding the intervention protocol, including dosage, frequency, and machine calibration for extracorporeal shockwave therapy. Without standardized reporting of these parameters, reproducibility is undermined and generalizability across clinical settings is restricted. This ambiguity increases the likelihood of variability in therapeutic outcomes, complicates the standardization of repeat procedures, and weakens the reliability of comparisons with similar studies. The importance of comprehensive reporting of shockwave therapy parameters to accurately evaluate efficacy and enable replication has been underscored in musculoskeletal research, as evidenced by de Menezes et al. ⁵

To advance the field, future research should incorporate stratification or covariate adjustment for demographic and lifestyle variables to more precisely capture treatment effects. Equally important is the integration of Doppler imaging, which can provide deeper insights into vascular changes and refine patient selection. To enhance data consistency and reliability, studies must also combine objective assessments with subjective patient‐reported outcomes while adhering to standardized follow‐up intervals. Moreover, the explicit reporting of intervention protocols, including dosage, frequency, and machine calibration, remains critical to ensure replicability and allow rigorous validation by the wider scientific community.

In light of these considerations, although the study by Pesaresi et al. ¹ provides valuable preliminary insights into the prognostic role of ultrasonographic features in calcific tendinopathy, its methodological constraints significantly temper the strength of its conclusions. The absence of demographic adjustment, the omission of Doppler vascular assessment, the reliance solely on subjective outcome measures, and the limited detail regarding treatment parameters collectively restrict the robustness and reproducibility of the findings. Future research that incorporates rigorous methodological standards, including demographic stratification, objective imaging endpoints, standardized follow‐up, and transparent reporting of shockwave protocols, will be essential to validate and extend the clinical implications of this promising line of investigation.

DISCLOSURE

The authors declare no conflict of interest.