Dynamic contrast-enhanced ultrasound and elastography assess deltoid muscle integrity after reverse shoulder arthroplasty

• Published in: Journal of shoulder and elbow surgery Vol. 26; no. 1; pp. 108 - 117
• Main Authors: Fischer, Christian, MD, Krammer, Daniel, Hug, Andreas, MD, Weber, Marc-André, MD, Kauczor, Hans-Ulrich, MD, Krix, Martin, MD, Bruckner, Thomas, PhD, Kunz, Pierre, MD, Schmidmaier, Gerhard, MD, Zeifang, Felix, MD
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 2017
• Subjects: Aged; Aged, 80 and over; ARFI; Arthroplasty, Replacement, Shoulder; Atrophy; CEUS; Cross-Sectional Studies; Deltoid muscle; Deltoid Muscle - diagnostic imaging; Deltoid Muscle - physiopathology; Elasticity Imaging Techniques; Electromyography; Female; Humans; Joint Diseases - diagnostic imaging; Joint Diseases - physiopathology; Joint Diseases - surgery; Male; Middle Aged; Orthopedics; Perfusion; Range of Motion, Articular - physiology; Reverse shoulder arthroplasty; Shoulder Joint; Treatment Outcome; Atrophy; Level IV; Diagnostic Study; Perfusion; ARFI; Deltoid muscle; Reverse shoulder arthroplasty; CEUS
• ISSN: 1058-2746; 1532-6500
• DOI: 10.1016/j.jse.2016.04.012

Background The outcome after reverse shoulder arthroplasty (RSA) depends on the condition of the deltoid muscle, which we assessed with new ultrasound modalities and electromyography (EMG). Contrast-enhanced ultrasound (CEUS) and acoustic radiation force impulse (ARFI) were applied to assess perfusion and elasticity of the deltoid muscle compared with the clinical and functional outcome. Methods The study recruited 64 patients (mean age, 72.9 years) treated with RSA between 2004 and 2013. The deltoid muscle was examined with EMG and ultrasound imaging. Functional scores such as Constant score and American Shoulder and Elbow Surgeons Standardized Shoulder Assessment Form score were assessed. Among other CEUS parameters, the wash-in perfusion index, time to peak, and rise time were compared between the operated-on and contralateral shoulders as well as between patients with above-average and below-average outcome. The stiffness of the deltoid muscle was analyzed with ARFI. Results After RSA, deltoid perfusion (wash-in perfusion index, Δ = −12% ± 22%, P  = .0001) and shoulder function (Constant score, Δ = −14 ± 24, P  < .0001) were both inferior compared with the contralateral side. This perfusion deficit was associated with a limited range of motion (time to peak and anteversion: r  = −0.290, P  = .022). Deltoid perfusion was higher in patients with above-average outcome (rise time, Δ = 33% ± 13%, P  = .038). The operated-on deltoid muscles showed higher stiffness than the contralateral muscles (ARFI, Δ = 0.2 ± 0.9 m/s, P  = .0545). EMG excluded functionally relevant axillary nerve injuries in the study population. Conclusions CEUS revealed reduced mean perfusion of the deltoid muscle after RSA. Reduced perfusion was associated with limited range of motion and below-average outcome. Functional shoulder impairment after RSA might be predicted by noninvasive CEUS as a surrogate parameter for the integrity of the deltoid muscle.