Clinical biomechanics
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Clinical biomechanics · Feb 2008
Influence of component positioning on impingement in conventional total shoulder arthroplasty.
Clinical experience suggests that component impingement can lead to eccentric implant loading and thereby cause glenoid loosening in conventional total shoulder arthroplasty. This study tests the hypothesis that certain implant component positioning configurations may lead to impingement within the physiological range of motion. ⋯ This study suggests that several intraoperatively adjustable implant positioning parameters can influence the likelihood of implant impingement in conventional total shoulder arthroplasty, and that the geometry of the humeral calcar should be taken into consideration when designing an operative strategy for shoulder joint replacement.
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This article proposes a new paradigm, "Orthopaedic sport biomechanics", for the understanding of the role of biomechanics in preventing and managing sports injury. Biomechanics has three main roles in this paradigm: (1) injury prevention, (2) immediate evaluation of treatment, and (3) long-term outcome evaluation. Related previous studies showing the approach in preventing and managing anterior cruciate ligament rupture and anterior talofibular ligament tear are highlighted. Orthopaedics and biomechanics specialists are encouraged to understand what they could contribute to the current and future practice of sports medicine.
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Clinical biomechanics · Jan 2008
Age affects the latency of the erector spinae response to sudden loading.
Aging and a past history of low back pain are risk factors for a future low back pain. Recent findings have demonstrated an impaired feed-forward control of paraspinal muscles during upper limb loading in low back pain patients as well as decreased feed-forward mechanism in elderly. The aims of the current study were to assess the age-related changes in paraspinal reflex latencies, flexion movement as well as flexion moment of the lumbar spine during sudden upper limb loading and the expectation effects via feed-forward mechanism on these postural responses. ⋯ These findings suggest that aging process is associated with a decreased motor control of the spine, particularly via reduced feed-forward control of paraspinal muscles. These findings may contribute to decreased ability to stabilize the spine and development of low back injury in elderly.
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Clinical biomechanics · Jan 2008
A new technique for cement augmentation of the sliding hip screw in proximal femur fractures.
Fractures of the osteoporotic proximal femur are a significant source of mortality and morbidity in today's ageing population. Even with modern fixation techniques such as the sliding hip screw, a certain percentage of fixations will fail due to cut-out of the screw. This study presents a new method for augmenting hip screws with cement to reinforce the fixation. ⋯ Several benefits with this technique have emerged. The method is technically straightforward. The risk of cement penetration into the joint is reduced, and cement is targetted to the areas of the femoral head where it is most needed. The exothermic reaction is minimised by reducing the volume of cement used. The first clinical results are promising.
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Clinical biomechanics · Dec 2007
ReviewA review of locking compression plate biomechanics and their advantages as internal fixators in fracture healing.
Metallic implants are often involved in the open reduction and internal fixation of fractures. Open reduction and internal fixation is commonly used in cases of trauma when the bone cannot be healed using external methods such as casting. The locking compression plate combines the conventional screw hole, which uses non-locking screws, with a locking screw hole, which uses locking head screws. ⋯ There are many factors which affect the functionality of the plate (e.g., screw placement, screw choice, length of plate, distance from bone, etc.). This paper presents a review of the literature related to the biomechanics of locking compression plates and their use as internal fixators in fracture healing. Furthermore, this paper also addresses the materials used for locking compression plates and their mechanical behavior, parameters that control the overall success, as well as inherent bone quality results.