Author reply to letter re: “Focal extracorporeal shockwave therapy in shoulder calcific tendinopathy: A retrospective observational study of sonographic prognostic factors”

Editor,

It is our great pleasure to have received valuable comments about our recent publication in your journal, our retrospective observational study about the potential sonographic prognostic factors to optimize the management of focal extracorporeal shockwave therapy in patients with shoulder calcific tendinopathy. ¹

As regards the comments on statistical analysis; we agree with the colleagues that adjustments of pain (numeric rating scale) and functional scores (Disabilities of the Arm, Shoulder and Hand, Shoulder Pain and Disability Index) for potential confounding factors such as demographic parameters, limb dominance, previous trauma, and psychological factors better define the “real” effectiveness of this physical therapy in clinical practice. Such additional statistical evaluation was not performed due to the relatively small size of the study cohort (n = 18 patients) as well as the possible individual subgroups. Certainly, the statistical assessments suggested by the authors are mandatory for a large study population to avoid biased interpretations of treatment effectiveness.

As regards the “Materials and Methods” section; detailed description of the treatment protocol has been already/accurately reported in the article to guarantee the reproducibility of this intervention by the readers; “The medical equipment used for the treatment was the Storz Medical Duolith SD1 T‐Top F‐SW Ultra, an electromagnetic shockwave generator. Three sessions, once per week, were performed using a setting of 1500 hits with a 3 Hz frequency and 0.45 mJ/mm² of maximal flux energy.” ¹

Lastly, regarding the role of color/power Doppler assessment in the management of patients with calcific tendinopathy of the shoulder; a few insights may be worth discussing. Technically, to accurately evaluate intratendinous hyperemia, a tendon should be relaxed. Instead, in Crass or modified Crass position (which are positions often used to scan/detect the calcification of the supraspinatus and infraspinatus tendon), the rotator cuff is put under tension, making the assessment of tendon microvascularization poorly accurate. Specifically, reduced visibility of small‐sized and low‐flow blood vessels due to a combined effect of traction and compression would be inevitable. This is the reason why—compared to other tendons like patellar ² and Achilles ³ tendons for which the intratendinous microvasculature can be easily evaluated in relaxed positions—the role of color/power Doppler assessment in the management of shoulder tendinopathy is less clinically relevant, poorly investigated and mainly focused on B‐mode ultrasound. Interestingly, in recent years, some authors have proposed the use of advanced softwares—for example, (superb) microvascular imaging—to optimize the challenging assessment of rotator cuff microvasculature and interpret its clinical significance. ⁴ Of note, these advanced sonographic techniques were not available on the equipment we used in our study.

DISCLOSURE

None of the authors, their immediate families and any research foundation with which they are affiliated received any financial payments or other benefits from any commercial entity related to the subject of this article.

DATA AVAILABILITY STATEMENT

The data that support the findings of this study are available on request from the corresponding author. The data are not publicly available due to privacy or ethical restrictions.