Clinical biomechanics
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Clinical biomechanics · Jan 2016
Use of shear wave ultrasound elastography to quantify muscle properties in cerebral palsy.
Individuals with cerebral palsy tend to have altered muscle architecture and composition, but little is known about the muscle material properties, specifically stiffness. Shear wave ultrasound elastography allows shear wave speed, which is related to stiffness, to be measured in vivo in individual muscles. Our aim was to evaluate the material properties, specifically stiffness, as measured by shear wave speed of the medial gastrocnemius and tibialis anterior muscles in children with hemiplegic cerebral palsy across a range of ankle torques and positions, and fascicle strains. ⋯ The higher shear wave speed in the more-affected limb of individuals with cerebral palsy indicates greater muscle stiffness, and demonstrates the clinical potential of shear wave elastography as a non-invasive tool for investigating mechanisms of altered muscle properties and informing diagnosis and treatment.
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Clinical biomechanics · Jan 2016
Antiglide plating of vertical medial malleolus fractures provides stiffer initial fixation than bicortical or unicortical screw fixation.
Vertical shear fractures of the medial malleolus (44-A2 ankle fractures) occur through a supination-adduction mechanism. There are numerous methods of internal fixation for this fracture pattern. ⋯ An antiglide plate construct provides the stiffest initial fixation while withstanding higher load to failure for vertical medial malleolus fractures when compared to unicortical and bicortical screw fixation.
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Clinical biomechanics · Jan 2016
Biomechanics of posterior instrumentation in L1-L3 lateral interbody fusion: Pedicle screw rod construct vs. transfacet pedicle screws.
The use of pedicle screws is the gold standard for supplemental posterior fixation in lateral interbody fusion. Information about the performance of transfacet pedicle screws compared to standard pedicle screws and rods in the upper lumbar spine with or without a lateral interbody fusion device in place is limited. ⋯ Posterior fixation with transfacet pedicle screws provides equivalent immediate stability to similarly sized pedicle screws. However, in the presence of a lateral interbody fusion device, pedicle screws seem to resist loosening more and may be a better option for fusion in the upper lumbar spine.