• Journal of Biomedical Engineering Research
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• v.23 no.2
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• pp.119-130
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• 2002

The nonlinear finite element program has been developed to analyze the design performance of an artificial hip prosthesis and long term behavior of a treated femur with stems made of composite material after cementless total hip arthroplasty(THA). The authors developed the three dimentional FEM models of femoral bone with designed composite stem which was taken with elliptic cross section of 816 brick elements under hip contact load and muscle farce in simulating single leg stand. Using the program, density changes, stress distributions and micromotions of the material femoral bone were evaluated by changing fiber orientation of stems for selected manufacturing method such as plate cut and bend mold. The results showed that the composite materials such as AS4/PEEK and T300/976 gave less bone resorption than the metallic material such as cobalt chrome alloy, titanium alloy and stainless steal. It was found that increasing the long term stability of the prosthesis in the femur could be obtained by selecting the appropriate ply orientation and stacking sequence of composite.

• Journal of the Korean Orthopaedic Association
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• v.55 no.6
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• pp.503-510
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• 2020

Purpose: Bipolar hemiarthroplasty is used as an alternative to open reduction and internal fixation for unstable intertrochanteric fractures in elderly patients. Recent advances in medical systems and technologies have resulted in increased survival rates after intertrochanteric fractures of the femur, requiring selection of the appropriate femoral stems considering the mid- to long-term duration of survival. Hemiarthroplasty was performed for unstable intertrochanteric fractures using a double tapered quadrilateral femoral stem (C2 stem), and the clinical and radiological results were evaluated as a five-year follow-up post-surgery. Materials and Methods: From January 2004 to December 2013, 43 patients (43 hips) who underwent hemiarthroplasty with a C2 stem were enrolled in this study. Their mean age was 78.6 years (range, 70-84 years), and the mean follow-up period was 85.4 months (range, 60-96 months). During the follow-up period, clinical parameters, such as the changes in pain, walking ability, and functional status, were examined. Radiologically, changes in the proximal femur, such as osteoporosis and bone resorption of cortical bone, were noted. Complications that occurred during the follow-up period, such as dislocation and prosthetic features, were also reviewed. Results: Initially, the pain was relieved postoperatively, but it increased four years after surgery. The walking ability was reduced by two steps in nine patients after 60 months, and the Harris hip score was reduced significantly postoperatively after two to three years. Radiologically, cortical osteoporosis occurred in 14 patients. Five patients developed cortical bone resorption. Four of them showed nonunion of the trochanteric fracture fragments, and three of them suffered reverse oblique fractures. Conclusion: Careful selection considering the general health condition and remaining lifespan of the patient would be necessary for primary hip hemiarthroplasty using a 3C type cementless femoral stem for unstable intertrochanteric fractures in elderly patients with osteoporosis.