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

Objective: To assess the potential prognostic role of sonographic parameters such as glenohumeral joint effusion, subacromial-subdeltoid bursitis, and the type of intratendinous calcific deposition to predict the clinical and functional outcomes of focal extracorporeal shockwave therapy (fESWT) in patients with calcific tendinopathy of the shoulder. Methods: This retrospective observational study included 18 patients (6 men and 12 women, mean age 63.5 ± 10.8 years) with shoulder calcific tendinopathy. Prior to treatment with fESWT the sonographic features of the shoulder were assessed and these findings were compared with the clinical and functional scores (Numeric Rating Scale [NRS]; Disabilities of the Arm, Shoulder and Hand [DASH]; and Shoulder Pain and Disability Index [SPADI]) measured before and 90 days after treatment. Each fESWT session was performed using a technical setting of 1500 hits with a 3 Hz frequency and 0.45 mJ/mm2 of maximal flux energy delivered by an electromagnetic shockwave generator. Results: The average posttreatment NRS, DASH, and SPADI values were significantly higher in patients with subacromial-subdeltoid bursitis than in patients without (6.29 ± 2.21 vs. 3.36 ± 1.75 for NRS, 44.09 ± 8.72 vs. 19.35 ± 7.13 for DASH, 44.08% vs. 27.38% for SPADI, with a p <.05 for all the scores), indicating worse clinical and functional outcomes. In patients with glenohumeral joint effusion, mean posttreatment clinical and functional scores were also higher than in patients without (5.40 ± 2.15 vs. 3.38 ± 1.70 for NRS, 33.64 ± 7.93 vs. 23.14 ± 6.12 for DASH, 39.64% vs. 33.14% for SPADI); but the results did not reach statistical significance (p >.05 for all the scores). Lastly, in patients with hard calcification and complete acoustic shadow, mean posttreatment clinical and functional scores were higher than in patients with soft calcification showing incomplete acoustic shadow and/or multiple calcific spots inside the tendon (5.44 ± 2.20 vs. 3.56 ± 1.20 for NRS, 35.31 ± 9.21 vs. 22.63 ± 7.44 for DASH, 42.31% vs. 33.88% for SPADI). However, the results did not reach statistical significance (p >.05 for all the scores). Conclusions: In patients with shoulder calcific tendinopathy who are referred for fESWT, the presence of subacromial-subdeltoid bursitis appears to be a potential negative prognostic factor for pain relief and functional improvement.