Quantified Mechanical Properties of the Deltoid Muscle Using the Shear Wave Elastography: Potential Implications for Reverse Shoulder Arthroplasty

Abstract

The deltoid muscle plays a critical role in the biomechanics of shoulders undergoing reverse shoulder arthroplasty (RSA). However, both pre- and postoperative assessment of the deltoid muscle quality still remains challenging. The purposes of this study were to establish a novel methodology of shear wave elastography (SWE) to quantify the mechanical properties of the deltoid muscle, and to investigate the reliability of this technique using cadaveric shoulders for the purpose of RSA. Eight fresh-frozen cadaveric shoulders were obtained. The deltoid muscles were divided into 5 segments (A1, A2, M, P1 and P2) according to the muscle fiber orientation and SWE values were measured for each segment. Intra- and inter-observer reliability was evaluated using intraclass correlation coefficient (ICC). To measure the response of muscle tension during RSA, the humeral shaft was osteotomized and subsequently elongated by an external fixator (intact to 15 mm elongation). SWE of the deltoid muscle was measured under each stretch condition. Intra- and inter-observer reliability of SWE measurements for all regions showed 0.761–0.963 and 0.718–0.947 for ICC(2,1). Especially, SWE measurements for segments A2 and M presented satisfactory repeatability. Elongated deltoid muscles by the external fixator showed a progressive increase in passive stiffness for all muscular segments. Especially, SWE outcomes of segments A2 and M reliably showed an exponential growth upon stretching (R2 = 0.558 and 0.593). Segmental measurements using SWE could be reliably and feasibly used to quantitatively assess the mechanical properties of the deltoid muscle, especially in the anterior and middle portions. This novel technique based on the anatomical features may provide helpful information of the deltoid muscle properties during treatment of RSA.

WITHDRAWN: Quantitative assessment of middle deltoid elasticity during different shoulder abduction using shear wave elastography: A preliminary study

“…Haizlip et al [21] showed that collagen and elastin architectures of muscle bers mainly determined MD elasticity, which may vary between different gender. It is also well con rmed that histologic changes in muscle structure could affect increased muscle strain [22][23][24][25]. However, there are not obvious difference at shoulder 90° abduction.…”

Posture‐related stiffness mapping of paraspinal muscles

“…With such complex anatomy, it is not possible to define only one fibre direction and to define the orientation of the ultrasound probe accordingly (Hatta et al. ).…”

Quantifying extensibility of rotator cuff muscle with tendon rupture using shear wave elastography: A cadaveric study

“…The technique is fast, convenient and applicable to a variety of clinical scenarios in which other approaches would potentially be inadequate; thus, it has been used successfully for breast cancers diagnosis (Athanasiou et al, 2010) and liver fibrosis staging (Ferraioli et al, 2014). In addition, quantitative assessments of the mechanical properties of skeletal muscles have also been investigated in in-vivo and in-vitr o studies (Akagi et al, 2015; Hatta et al, 2016a; Hirata et al, 2015; Hug et al, 2013). …”