• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2004년도 추계학술대회 논문집
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• pp.389-392
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• 2004

It is clinically well known that pre-tension of wires increases the fracture stability in ring or hybrid external fixation. In some cases, additional half pin should be necessary to increase the stability when soft tissue impalement occurs during fixation. In this paper, the fracture stability of a hybrid external fixator system with different pre-tension effects and additional half-pins was analysed using FEM to investigate the effects of these pre-tension and half pin on the system stability quantitatively. 3-D finite element models of five different fixator frames were developed using by beam elements. In axial compression analysis, the fracture stiffness was increased maximally 62％ as the pre-tension increased. In torsion analysis, in the other hand, there is little variations in the fracture stiffness. Additional half pin increased the system stiffness about 200 ％. From the results, proper pre-tension and additional half pin would provide good methods to increase the fracture stability of the hybrid external fixator and provide more surgical options to minimize soft tissue damage at the fracture site.

• 대한족부족관절학회지
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• 제14권2호
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• pp.140-145
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• 2010

Purpose: The diabetic charcot neuroarthropathy of ankle is an infrequent site (around 5%), but is definitely the location that, because of the instability and progressive deformity it involves, cause ulceration in a high percentage of patients, and this can then become a reason for amputation. However, the treatment of this disastrous disease is still challenging. We analyzed the clinical and radiological results of ankle arthrodesis by our fixation method in Charcot neuroarthropathy. Materials and Methods: Seven cases that were diagnosed as charcot neuroarthropathy of ankle arthrodesis were followed for more than 16 months postoperatively. Mean age was 57 years, and the mean follow-up period was 27 months. Anterior approach was used in arthrodesis, and internal fixation by 3 or more cannulated screws and hybrid type external fixation were used. Auto iliac bone for grafting was combined in all cases. External fixator was kept for 3 months without weight-bearing. Then, boots brace was applied for more 3 months allowing partial weight-bearing. Four cases had minor complications such as pin site infection. Preoperative and postoperative AOFAS score, time to fusion and postoperative complications were checked. Results: Postoperative fusion was completed in all cases, and the mean time to fusion was 3.4 months. No postoperative complication was checked. At the last follow-up, the mean AOFAS score had increased from 54 points to 72 points. Patient's satisfaction was over 80%. Conclusion: Satisfactory results were obtained after ankle arthrodesis using internal and hybrid type external fixation combined with auto iliac bone graft in charcot neuroarthropathy with minor complications.