September 2022

Evaluation of muscle stiffness in Adhesive Capsulitis with MyotonPRO

Authors: Kurashina Wataru 1, 2, Yuki Iijima 3, Hideyuki Sasanuma 3, Tomohiro Saito 3, Katsushi Takeshita 3


  1. Tochigi Medical Center Shimotsuga, Department of Rehabilitation, 420-1 Kawatsure, Ohira, Tochigi 3294498 Japan
  2. Graduate School of Medicine, Jichi Medical University, Tochigi, Japan
  3. Jichi Medical University, Department of Orthopaedic Surgery, 3311-1 Yakushiji, Shimotsuke, Tochigi 3290498, Japan

Journal: JSES International - September 2022, In Press, Journal Pre-proof (DOI: 10.1016/j.jseint.2022.08.017)

  • In this study, we found that MyotonPRO is a highly reproducible device that correlates with SWE.
  • We showed that intra-and inter-rater reliabilities with MyotonPRO were very high.

Background: Adhesive Capsulitis (AC) is characterized by pain and limited range of motion (ROM), caused by stiffness of the joint capsule and coracohumeral ligament. On the other hand, there have been few reports on muscle stiffness in AC. The purpose of this study was to assess muscle stiffness in patients of AC with a portable and non-invasive device, MyotonPRO. We hypothesized that muscle stiffness around shoulder joint increases in AC.

Methods: At first, we surveyed correlation between MyotonPRO and shear wave elastography (SWE) with phantoms. Second, reproducibility and repeatability of healthy volunteers with MyotonPRO were evaluated. Finally, muscle stiffness was measured in 40 patients who were diagnosed with AC. Muscle stiffness was quantitatively measured with MyotonPRO. We compared the stiffness of the anterior deltoid (AD), pectoralis major (PM), and latissimus dorsi (LD) in FS patients on both the affected and non-affected sides.

Results: Correlation coefficient in SWE and MyotonPRO was 0.99(p=0.001). Reliability of intra- and inter-operator with MyotonPRO was 0.9 or higher. Muscle stiffness values (N/m) of the AD, PM, and LD were 355±61, 252±54, 207±51 in affected sides and 328±50, 252±41, 186±37 in non-affected side, and the differences were significant in the AD and LD (p=0.005, p=0.002, respectively).

Conclusions: We used MyotonPRO to evaluate muscle stiffness in FS. The AD and LD muscles of AC patients were significantly stiffer on the affected side compared to the non-affected side.


Figure 2. Results of correlation between SWV and stiffness Correlation coefficient for SWV in SWE and stiffness in Myoton PRO was 0.99 (P<0.001).


Keywords: adhesive capsulitis, muscle stiffness, MyotonPRO, shear wave elastography, anterior deltoid, pec major, latissimus dorsi

MyotonPRO may be a helpful device to evaluate muscle stiffness in a specific part. In AC, there was significant stiffness in the AD and LD. In addition to the joint capsule and CHL, stiffness of the AD and LD could warrant further exploration in regard to their role in management of AC.