Contribution of shear wave elastography in evaluation of the deltoid in reverse shoulder arthroplasty: reproducibility study and preliminary results

Abstract

The current difficulty of reverse shoulder arthroplasty (RSA) is soft tissue management, and adequate deltoid tensionand at present there is no consensus and available tools (X-ray, MRI, EMG) remain difficult to apply in clinical follow-up.The objective of this study was (1) to determine reliability and feasibility of deltoid elasticity assessment using ultrasound elastographyand (2) to assess the change of deltoid stiffness after RSA by comparing shear wave speed (SWS) between healthyand RSA shoulders. Twenty-six healthy (native shoulder, painless and complete range of motion)subjects and twelve patients with RSA were included. Two independent investigators performed 3 measurements on each segment.Measurements were bilateral. Anterior segment was also evaluated at 45° and 60° of passive abduction. Reliability andfeasibility have been assessed (ISO5725-standard). Coefficient of measurements variation was less than 6.1% and0.13 m/s. In the healthy group, SWS was not significantly different between anterior and middle segments; however, the SWSof the posterior segment was significantly lower than others (p<0.0001). In abduction position, compared to the rest position,SWS of the anterior segment decreased at 45° abduction (p=0.0003) and increased at 60° abduction (p<0.0001). Variability ofmeasurement was higher in the RSA group. No significant difference was found between the SWS measurement of the operatedand non-operated side. SWS measurements of the operated side of the anterior and middle segment were significantlyhigher compared to the healthy group. In abduction position, compared to rest position, no difference in SWS of the anteriorsegment was found at 45° abduction (p=0.71) and nor at 60° abduction (p=0.75). This study demonstrated feasibilityand reliability of shoulder assessment with shear wave elastography. Reference values for asymptomatic patients canalready be used in future studies on shoulder pathology and surgery.