Clinical biomechanics
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Clinical biomechanics · Mar 2011
Long-term functional implications of the iatrogenic rotational malalignment of healed diaphyseal femur fractures following intramedullary nailing.
The long-term functional implications for patients with iatrogenic femoral malrotation following femoral intramedullary nail fixation remain unclear. This study examined the extent and direction of rotational alignment of the femur treated with intramedullary nail fixation and its long-term functional effects on patients' standing, walking, and subjective outcome. ⋯ Patients can compensate for even significant femoral malrotation and tolerate it well. External femoral malrotation appears to be better compensated/tolerated than internal malrotation.
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Clinical biomechanics · Mar 2011
Comparative StudyBiomechanical evaluation of fixation strength of conventional and expansive pedicle screws with or without calcium based cement augmentation.
The expansive pedicle screw was originally developed to be installed in the bone of compromised quality, but there are some concerns whether it can provide enough fixation strength in the spine with osteoporosis or severe osteoporosis. ⋯ Our results demonstrate that (i) the expansive pedicle screw appears feasible and safe in either osteopenic or osteoporotic spine; (ii) calcium based cement augmentation can offer improved initial fixation strength of pedicle screws.; and (iii) no screw placement protocol we examined is efficacious in the bone at the severely osteoporotic level.
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Clinical biomechanics · Mar 2011
The effects of prosthetic ankle dorsiflexion and energy return on below-knee amputee leg loading.
Prosthetic devices are intended to return lower limb amputees to their pre-amputation functional status. However, prosthetic devices designed for unilateral below-knee amputees have yet to completely restore the biomechanical functions normally provided by the ankle muscles, leading to gait asymmetries and increased reliance on their intact leg. In an effort to improve amputee gait, energy storage and return feet have been developed that store mechanical energy in elastic structures in early to mid-stance and return it in late stance. However, little is known regarding how ankle compliance and the level of energy return influences walking mechanics. The purpose of this study was to identify the influence of prosthetic ankle dorsiflexion and energy storage and return on leg loading during steady-state walking. ⋯ These results provide insight into the relationships between ankle dorsiflexion, energy storage and return, and leg loading, which may lead to more effective prosthetic devices to improve amputee gait.