Clinical biomechanics
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Clinical biomechanics · Oct 2015
The influence of simulated transversus abdominis muscle force on sacroiliac joint flexibility during asymmetric moment application to the pelvis.
The role of so-called local muscle system in motor control of the lower back and pelvis is a subject of ongoing debate. Prevailing beliefs in stabilizing function of this system were recently challenged. This study investigated the impact of in vitro simulated force of transversely oriented fibres of the transversus abdominis muscle (a part of the local system) on flexibility of the sacroiliac joint during asymmetric moment application to the pelvis. ⋯ A lack of a stiffening effect of simulated transversus abdominis force on the sacroiliac joint was demonstrated. Earlier hypotheses suggesting a stiffening influence of this muscle on the pelvis cannot be confirmed. Consistent with previous findings smaller flexibility of the joint recorded during posterior rotation of the innominate may be of clinical importance for physio- and manual therapists. However, major limitations of the study should be acknowledged: in vitro conditions and simulation of only solitary muscle force.
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Clinical biomechanics · Oct 2015
Interfragmentary lag screw fixation in locking plate constructs increases stiffness in simple fracture patterns.
The aim of the current biomechanical cadaver study was to quantify the influence of an additional lag screw on construct stiffness in simple fracture models at the distal femur stabilised with a locking plate. ⋯ The current biomechanical testing unveils that the insertion of a lag screw combined with a locking plate dominates over a bridging plate construct at the distal femur in terms of axial and torsional stiffness.
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Clinical biomechanics · Aug 2015
The effects of movement speed on kinematic variability and dynamic stability of the trunk in healthy individuals and low back pain patients.
Comparison of the kinematic variability and dynamic stability of the trunk between healthy and low back pain patient groups can contribute to gaining valuable information about the movement patterns and neuromotor strategies involved in various movement tasks. ⋯ Our findings suggest that slower pace flexion-extension trunk movements are associated with more motor variation as well as local and orbital stability, implying less potential risk of injury for the trunk. Individuals with and without low back pain consistently recruited a closed-loop control strategy towards achieving trunk stability. Chronic low back pain patients exhibited more stable trunk movements over long-term periods, indicating probable temporary pain relief functional adaption strategies. These results may be used towards the development of more effective personalized rehabilitation strategies and quantitative spinal analysis tools for low back pain detection, diagnosis and treatment, as well as improvement of workspace and occupational settings.
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Clinical biomechanics · Aug 2015
Posterior tibial slope and femoral sizing affect posterior cruciate ligament tension in posterior cruciate-retaining total knee arthroplasty.
During cruciate-retaining total knee arthroplasty, surgeons sometimes encounter increased tension of the posterior cruciate ligament. This study investigated the effects of femoral size, posterior tibial slope, and rotational alignment of the femoral and tibial components on forces at the posterior cruciate ligament in cruciate-retaining total knee arthroplasty using a musculoskeletal computer simulation. ⋯ These findings suggest that accurate sizing and bone preparation are very important to maintain posterior cruciate ligament forces in cruciate-retaining total knee arthroplasty. Care should also be taken regarding malrotation of the femoral and tibial components because this increases posterior cruciate ligament tension.
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Clinical biomechanics · Jul 2015
ReviewThe effect of exercise therapy on knee adduction moment in individuals with knee osteoarthritis: A systematic review.
Exercise therapy is an evidence-based intervention for the conservative management of knee osteoarthritis. It is hypothesized that exercise therapy could reduce the knee adduction moment. A systematic review was performed in order to verify the effects of exercise therapy on the knee adduction moment in individuals with knee osteoarthritis in studies that also assessed pain and physical function. ⋯ Clinical benefits from exercise therapy were not associated with changes in the knee adduction moment. The lack of knee adduction moment reduction indicates that exercise therapy may not be protective in knee osteoarthritis from a joint loading point of view. Alterations in neuromuscular control, not captured by the knee adduction moment measurement, may contribute to alter dynamic joint loading following exercise therapy. To conclude, mechanisms other than the reduction in knee adduction moment might explain the clinical benefits of exercise therapy on knee osteoarthritis.