Article
Dynamic contrast-enhanced ultrasound (CEUS) and elastography assess deltoid muscle integrity after reverse shoulder arthroplasty
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Authors
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Daniel Krammer
- Orthopädie und Unfallchirurgie Heidelberg, Heidelberg, Germany
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Felix Zeifang
- Orthopädie und Unfallchirurgie Heidelberg, Heidelberg, Germany
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Andreas Hug
- Klinik für Paraplegiologie Heidelberg, Heidelberg, Germany
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Arash Moghaddam-Alvandi
- Orthopädie und Unfallchirurgie Heidelberg, Heidelberg, Germany
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Gerhard Schmidmaier
- Orthopädie und Unfallchirurgie Heidelberg, Heidelberg, Germany
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Christian Fischer
- Orthopädie und Unfallchirurgie Heidelberg, Heidelberg, Germany
| Published: | October 10, 2016 |
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Outline
Text
Objectives: The treatment of choice for cuff tear arthropathies is the reverse shoulder arthroplasty (RSA). Its outcome depends on the condition of the deltoid muscle, which we assessed with contrast-enhanced ultrasound (CEUS), acoustic radiation force impulse imaging (ARFI) and electromyography (EMG).
Methods: 64 patients (mean age 72.9 years) treated with RSA between 2004 and 2013 were recruited in this cross-sectional study. EMG and ultrasound of the deltoid muscle were performed; the outcome was assessed with functional scores. CEUS parameters like Wash-in Perfusion Index (WiPI) and Time To Peak (TTP) were referenced to the posterior humeral circumflex artery and compared between the operated and contralateral shoulders. The elasticity of the deltoid muscle was analyzed with ARFI. Possible differences for continuous data between operated and contralateral shoulders were evaluated using one sample t-test, possible differences between groups were evaluated using Wilcoxon U-test. Pearson correlation coefficients were calculated to show association between functional parameters, ultrasound perfusion and ARFI parameters.
Results and Conclusion: Compared to the contralateral shoulder, perfusion of the deltoid muscle after RSA was 12±22% lower (WiPI, p=0.0001) and the function as measured by the Constant score was impaired (Δ=-14±24, p<0.0001). This perfusion deficit was associated with a limited range of motion (TTP and anteversion: r=-0.290, p=0.022). Moreover, a trend towards increased ARFI suggested higher deltoid muscle stiffness after RSA (Δ=0.2±0.9m/s, p=0.0545). The length of the postoperative interval had no effect on these parameters. EMG excluded functionally relevant axillary nerve injuries in the study population.
CEUS and ARFI analyses revealed reduced perfusion and increased tension of the deltoid muscle after RSA. Reduced perfusion was associated with limited range of motion. Functional shoulder impairment after RSA might be predicted by CEUS and ARFI as surrogate parameters for the integrity of the deltoid muscle. These techniques could be integrated into prospective studies that focus on the deterioration of the deltoid muscle function after RSA.
