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Objective To evaluate the effect of different degrees of pubic symphysis diastasis on the stress distribution of posterior pelvic ring. Methods Eight embalmed pelvis and articulated proximal 1/3 of the femurs were harvested for this study. The samples were positioned as both legs standing straight and loaded to 600 N on the on the CSS-44020 biomechanical machine. The strain gages were adhered to 38 sites distributed symmetrically on the two sides of sacroiliac joint, anterior sacrum and posterior ilium. The strain gages were connected to WS3811 digital strainometer to record strain changes of the intact pelvic ring and at 1,2, 2.5 cm of pubic symphysis diastasis. Results Elastic changes occurred in the cortical bone of the pelvis under 600 N load. The symmetrical sites had similar strain changes without significant difference in the intact pelvic ring and at 1,2, 2.5 cm of pubic symphysis diastasis ( P ＞0.05 ). The sites with more strain changes were distributed on the iliofemoral arch in the intact pelvis.The strain changes were increased significantly frona the posterolateral sites to the iliofemoral arch. But the strain changes on the iliofemoral arch were decreased significantly during pubic symphysis diastasis.Conclusion The conduction of vertical load runs along the sacrofemoral arch in the intact pelvic ring and redistributes posterolaterally during pubic symphysis diastasis.
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Objective To evaluate the effects of post-operation rehabilitation treatment of patients with calcaneus fracture by dynamic plantar pressure analysis,and assess the value of the Footscan system.Methods Sixty-two patients with unilateral calcaneus fracture were randomly divided into a rehabilitation group and a control group.The patients in the rehabilitation group were given early,systemic standard rehabilitation treatment,while those in the control group took functional exercise following the doctors'advice.At 3 months and 6 months after operation,the plantar pressure distribution of the patients in both groups was analyzed with the Footscan system,respectively.Results After 3 months of treatment.there was statistically significant difference between the injured and the uninjured sides in both groups,with regard to the contact time,average plantar pressure and pressure-time integrals at different phases of gait.However,there was no significant difference between the injured and the uninjured sides after 6 months in rehabilitation group.But in control group,there was still statistically significant difference between the two sides with regard to the above parameters.Conclusion Early rehabilitation treatment could significantly improve the function outcome of patients with calcaneus fracture.Footscan System can objectively evaluate the recovery of the calcaneous fracture.
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BACKGROUND: Dynamic hip screw (DHS) is a standard internal fixation for intertrochanteric fracture, whereas the patient combined with osteoporosis, cut-out incidence of lag screw is common. The articles in China and abroad indicate bone cement augmentation of DHS to achieve firm fixation. As for normal bone, no reports is published that whether bone cement augmentation is effective.OBJECTIVE: To investigate the biomechanics of DHS with bone cement augmentation for the fixation of intertrochanteric fracture specimen that has a normal bone density.DESIGN, TIME AND SETTING: Bilateral contrast observation study of the same sample was performed in the Laboratory of Biomechanics, Hebei Orthopaedic Research Institute (Shijiazhuang, Hebei Province, China) between March and April In 2005.MATERIALS: Bilateral upper femora from the embalmed male cadaver were provided by Anatomy Department of Hebei Medical University (China). X-ray scan results proved the absence of tuberculosis, anatomical deformity and tumor.METHODS: Twenty-four matched pairs of the upper femora (48 sides) were used to make the specimens of the intertrochanteric fracture of type A2. The right femur specimens were fixed with DHS augmented by bone cement, as the augmentation group (The screw track of femoral neck was expended by curette, and the femoral head facing upwards were injected with 2mL low viscosity bone cement. Then lag screw was wrested to keep the position unchanged till the bone cement coagulated. Placing barrel, compressing through tighten tail screw, and cortical screw fixing side-plate were. followed). And the left femur specimen was fixed with DHS conventional fixation, as the control group. The bending and torsional tests were performed in the two groups.MAIN OUTCOME MEASURES: The maximum load and the maximum torque in the two groupsRESULTS: The maximum load and the maximum torque were (3852.1602±143.6031) N and (15.5+2.6) Nm in the augmentation group, and (3702.9667±133.8601) N and (14.7±3.4) Nm in the control group. There was no significant difference in the biomechanical effects between the two groups (P>0.05).CONCLUSION: The augmenting fixation with bone cement for intertrochanteric fracture specimen has no significant effect on the strength of DHS fixation or on the overall stability of the fractured bone in normal bone density.
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0.05).There was not remarkable relativity between HVA.IMA and AB/CD in normal feet,but there is remarkable relativity in hallux valgus feet.[Conclusion].The fist metatarsal sesamoids system plays an important role in the pathogensis of hallux valgus.