Use of shear wave elastography to analyze the muscle structure in children with spastic cerebral palsy.

Purpose: In children with cerebral palsy (CP), gastrocnemius muscle spasticity may lead to pes equinus posture which causes insufficient ankle joint dorsiflexion for normal gait. The aim of this study was to analyze the stiffness of gastrocnemius and tibialis anterior muscles by shear wave elastography (SWE) in children with pes equinus deformity due to spastic CP.

Methods: 24 legs of 12 children (6 females and 6 males, mean age 45.8 months) with CP were prospectively included in the study. Tissue stiffness quantification with shear-wave velocity (SWV) was analyzed.

Results: The mean SWVs of the gastrocnemius and tibialis anterior muscles were 3.91±0.26 m/s and 2.67±0.18 m/s, respectively. The stiffness of the gastrocnemius muscle was significantly higher than the stiffness of the tibialis anterior muscle (p < 0.0001). There was no correlation between the stiffness of these muscles (r = 0.129, p > 0.05).

Conclusion: Gastrocnemius muscles were stiffer than tibialis anterior muscles in patients with spastic CP. But stiffness between these muscles was not correlated with each other. Pes equinus may be related to stiff gastrocnemius in these patients. This study demonstrates the clinical potential for SWE as a non-invasive tool for analyzing calf muscle stiffness.