Comparison of the Effect of Radial Shock Wave, Ultrasound-guided Needle Puncture, and Combination of Both in the Treatment of Calcific Tendinitis of the Shoulder

Calcific tendinitis of the shoulder is a common enthesopathy, and is characterized by inflammation around calcium hydroxyapatite crystal deposits, usually located in the supraspinatus tendon, near its insertion place.1 The disease mainly affects individuals between 30 and 50 years of age, is painful in 50% of patients and frequently leads to considerable restriction of motion.2,3 It goes through three distinct stages: a precalcific stage (metaplasia of matrix), calcific stage (calcification of matrix and resorption of calific deposits), and a postcalcific stage (reconstitution of matrix).

Classifications of calcific tendinitis have been proposed previously. Gartner proposed a classification based on plain films of the shoulder: type I deposits were sharply outlined and densely structured. Type III deposits had a cloudy outline and were transparent in structure. Type II deposits were features of both.4 Type III plaques have a tendency to resorb. Due to the progress of musculoskeletal ultrasound over the past decade, classification of the calcific tendinitis based on ultrasound findings was also proposed: arc-shaped (an echogenic arc with clear shadowing), fragmented or punctate (at least 2 separated echogenic spots or plaques with or without shadowing), nodular (an echogenic nodule without shadowing), and cystic (a bold echogenic wall with an anechoic area).5 Plaques that appear fragmented, nodular, or cystic on ultrasound are considered in the resorptive phase.

The treatment of patients with calcific tendinitis is typically conservative. The reported success rates vary between 30 and 85%.6 If the pain becomes chronic or intermittent after several months of conservative treatment, arthroscopic and open procedures are available to curette the calcium deposit, and additional subacromial decompression can be performed if necessary.7,8 As an alternative, minimally invasive extracorporeal shock wave therapy (ESWT) has been postulated to be an effective treatment option for treating calcific tendinopathy of the shoulder, before surgery.9-12 In recent years, radial shock wave has been developed. A radial shock wave is a low- to medium-energy shock wave that is pneumatically generated through acceleration of a projectile inside the handpiece of the treatment device and then transmitted radially from the tip of the applicator to the target zone. Radial shock wave showed a low pressure and a considerably longer rise time than extracorporeal shock wave. In radial shock wave therapy (RSWT), the focal point is not concentrated on the target zone, as occurred in ESWT, but on the tip of applicator. 13 Another new method of conservative treatment of calcific tendinopathy is ultrasound-guided fine-needle repeated puncture of the calcific plaque, as shown in previous study.14,15 The new method has the advantage of being easily operative, cheap, safe, and has a proven high success rate. Although percutaneous needle aspiration with a large size needle(≥ 18# needle) alleviates symptoms in up to 60% of patients and resolves the deposits in 40% to 74%,16,17 the larger size needle could result in tendon injury.

In clinical practice, combination of radial shock wave therapy and ultrasound-guided fine needle repeated puncture is frequently used and shows promising results, however, scientific report has been rarely published before.18 The purpose of this study is to compare the efficacy of RSWT, ultrasound-guided fine needle puncture (USNP), and combination of RSWT and USNP in the treatment of calcific tendinitis of shoulder.