• Journal of Biomedical Engineering Research
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• v.19 no.5
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• pp.503-511
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• 1998

In this study, the stress distribution for different tibial components was observed In order to Investigate the load transfer and potential failure mechanism of the tibial components subjected to dynamic impact loading and also to evacuate the effect of bone-implant bonding conditions on the implant system. The 3-dimensional finite element models included an intact tibia, cemented metal-backed tibial component, uncemented metal-blocked tibial component, cemented all-polyethylene tibial component, and metal-backed component with a debonded bone/stem interface. The results showed that the cemented metal-hocked component Induced slightly higher peak stress at stem tip than the uncemented component. The peak stress of the all-polyethylene tibia1 component at stem trip showed about half thats of metal-backed tibial components. The all-polyethylene component showed a similar dynamic response to intact tibia. In case of debonded bone/stem interface, the peak stress below the metal tray was three times Higher than that of the fully bonded interface and unstable stress distribution at the stem tip was observed with time, which causes another adverse bone apposition and implant loosening. Thus, the all-polyethylene tibial component bonded fully to the surrounding bone might be most desirable system under an impact loading.

• The Journal of the Korean bone and joint tumor society
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• v.6 no.1
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• pp.22-29
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• 2000

Purpose : The purpose of the current study was to report the results of curettage and en bloc excision as well as to introduce how to excise the nidus percutaneously with Halo-mill. Material and Methods : Twenty patients(14 men and 6 women) were evaluated, who had operative treatments after diagnosed as osteoid osteoma from March 1990 to January 1998. These patients ranged in age from 7 to 42 years(average: 20.8 years). Locations were 9 femurs, 6 tibias, 2 vertebras, 1 ulna, 1 maxilla and 1 skull. Nine femoral lesions included 5 proximal metaphysis, 2 neck and 2 diaphysis, while 5 tibial lesions included 3 diaphysis, 1 proximal metaphysis and 1 distal metaphysis. We used simple radiography, bone scan, CT and MRI for the accurate diagnosis and localization. As for surgical treatments, while excision and curettage had to need open-exposure of lesion, the percutaneous excision of nidus did not need openexposure : guided Halo-mill into K-wire inserted to nidus under image intensifier. Results : Simple radiography showed that 10 cases had typical nidus and others had only cortical sclerosis. Bone scan was performed at 14 cases and all had hot uptake except one case. We used CT in 10 cases and MRI in 4 cases as diagnostic methods, of which 1 case didn't reveal nidus at CT. Surgical treatment consisted of 6 curettages, 11 excisions, 2 percutaneous excisions with halo-mill and 1 total elbow arthroplasty. We used 7mm sized Halo-mill. During the follow-up period, all patient relieved symptoms and there were no recurrences. All had histologically typical findings except one which had hyperostosis without nidus. Conclusion : Complete removal of the nidus is the most important factor in the treatment. We could excise the nidus percutaneously in 2 cases with the minimal injury to surrounding soft tissues. If we could evaluate the precise location, size of nidus and percutaneous acccesibility, the percutaneous excision of nidus with Halo-mill could be an alternative method as a treatment of osteoid osteoma.