| Budget Amount *help |
¥1,800,000 (Direct Cost: ¥1,800,000)
Fiscal Year 1988: ¥700,000 (Direct Cost: ¥700,000)
Fiscal Year 1987: ¥1,100,000 (Direct Cost: ¥1,100,000)
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| Research Abstract |
Through the clinical experience of performing head bipolar hipprosthesis, we came to believe that it might be possible to improve this prothesis by changing the head from a metalic one to an alumina ceramic one. we accordingly developed a new bipolar hip prosthesis with an alumina ceramic outer head which is much more bioinert than a metallic one. This prototype modelwas tested with static load, impact force and repeated load, and having passed these tests well, we judged that it had enough strength for practical clinical use.
Therefore we used this model clinically in femoral neck fracture, aseptic femoral head mecrosis and osteoarthritis. No problems in clinical and X-ray findings have been shown in thesecases to date, and all patients have rated the results as satisfactorily. The center was made offset in this model, in expectation of the so-called self-centering effect. This effect is discussed biomechanically using a mathematical model from thepoint of view of the differences of the head size and the frictional coefficient between metal and aluminaceramics.
Now, we developed new model, which has alumina ceramic outer and inner head, with press fit type tifanium alloy stem and have used this model for osteo orthritis as bone cementless total hip prosthesis. These clinical experiences are verysuccessfully, and we are satisfied very much with clinical results.
From 1987, to 1988, we performed 45joints replacement with thisprosthesis, and clinical results of these patients are 79.8points in J. O. A. score average.
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