Clinical biomechanics
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Clinical biomechanics · May 2008
Controlled Clinical TrialEffects of Parkinson's disease and levodopa on functional limits of stability.
The voluntary, maximum inclined posture reflects the self-perceived limits of stability. Parkinson's disease is associated with small, bradykinetic postural weight shifts while standing but it is unclear whether this is due to reduced limits of stability and/or to the selection of abnormal strategies for leaning. The aim of this study was to investigate the effects of Parkinson's disease and levodopa medication on voluntary limits of stability and strategies used to reach these limits. ⋯ Parkinson's disease reduces functional limits of stability as well as the magnitude and velocity of postural preparation during voluntary, forward and backward leaning while standing. Levodopa improves the limits of stability but not the postural strategies used to achieve the leaning.
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Clinical biomechanics · Mar 2008
Clinical TrialWeight bearing after tibial fracture as a guide to healing.
Judging when it is safe to remove an external fixator or plaster cast requires clinical and radiological assessment, both of which are subjective. Weight bearing has been shown to increase with time post-fracture and we hypothesised that it could be used as an objective measure of fracture healing. ⋯ Weight bearing correlates reasonably well with fracture stiffness. It is quicker and easier to measure than fracture stiffness and potentially has relevance to other fracture fixation methods.
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Clinical biomechanics · Mar 2008
Examining outcomes from total knee arthroplasty and the relationship between quadriceps strength and knee function over time.
Temporal-spatial gait parameters improve following total knee arthroplasty (TKA) but lower limb kinematics and moments fail to match those of age-matched healthy individuals. The aim of this study was to determine whether quadriceps strength, clinical measures of knee function, lower limb kinematics, and joint moments improve following arthroplasty and normalize over time. ⋯ Patients who have undergone TKA demonstrate improvements in function as measured by self-report and functional performance measures. Gait becomes more symmetric and quadriceps strength becomes stronger. Some approached the values of healthy control subjects. Important differences still remain however. The larger hip extensor contribution to the total support moment may be to compensate for the diminished knee extensor contribution during level walking. Since instrumented gait analysis and functional performance measures appear to reflect different aspects of recovery following total knee replacement, both should be considered when evaluating gait and function.
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Clinical biomechanics · Feb 2008
Can a modified interspinous spacer prevent instability in axial rotation and lateral bending? A biomechanical in vitro study resulting in a new idea.
Interspinous spacers are mainly used to treat lumbar spinal stenosis and facet arthrosis. Biomechanically, they stabilise in extension but do not compensate instability in axial rotation and lateral bending. It would therefore be desirable to have an interspinous spacer available, which provides for more stability also in these two planes. At the same time, the intervertebral disc should not completely be unloaded to keep it viable. To meet these requirements, a new version of the Coflex interspinous implant was developed, called "Coflex rivet", which can be more rigidly attached to the spinous processes. The aim was to investigate whether this new implant compensates instability but still allows some load to be transferred through the disc. ⋯ The new Coflex rivet seems be a suitable option to compensate instability. Its biomechanical characteristics might even make it suitable as an adjunct to fusion, which would be a new indication for this type of implant.