Bonding behavior of a glass-ceramic containing apatite and wollastonite in segmental replacement of the rabbit tibia under load-bearing conditions.
Glass-ceramic implants containing apatite and wollastonite were studied under load-bearing conditions in a segmental replacement model in the tibia of the rabbit. Alumina-ceramic implants were used as a control. A sixteen-millimeter segment of the middle of the shaft of the tibia was resected at a point distal to the junction of the tibia and the fibula. The defect was replaced by a fifteen-millimeter-long hollow, cylindrical implant that was fixed by intramedullary nailing using a Kirschner wire. Two groups of eight rabbits each (one group with a glass-ceramic implant and the other with an alumina implant) were killed twelve weeks after implantation. Two similar groups were killed twenty-five weeks after implantation. The segment of the tibia that contained the implant was excised and tension-tested. The load to failure of glass-ceramic implants containing apatite and wollastonite increased with time. The loads to failure of the glass-ceramic and alumina implants at twelve weeks after implantation were 19.8 +/- 7.06 and zero newtons, respectively. The loads to failure of glass-ceramic and alumina implants at twenty-five weeks after implantation were 126.4 +/- 32.54 and 19.6 +/- 13.92 newtons, respectively. No glass-ceramic implants broke. A calcium-phosphorus layer at the interface of the glass-ceramic and the bone was observed by scanning electron microscopy and electron-probe microanalysis. There was no interposition of soft tissue between the glass-ceramic and the bone, as observed by Giemsa surface staining.
Kitsugi
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Department of Orthopaedic Surgery, Faculty of Medicine, Kyoto University, Japan.
Yamamuro
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Kokubo
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D000537:Aluminum Oxide; D000818:Animals; D001031:Apatites; D001696:Biomechanical Phenomena; D017610:Calcium Compounds; D002516:Ceramics; D005898:Glass; D066298:In Vitro Techniques; D019736:Prostheses and Implants; D011817:Rabbits; D017640:Silicates; D012824:Silicic Acid; D013314:Stress, Mechanical; D013977:Tibia / Q000473:pathology / Q000503:physiopathology / Q000601:surgery*
D001031:Apatites; D017610:Calcium Compounds; D017640:Silicates; D012824:Silicic Acid; D000537:Aluminum Oxide; C031293:calcium silicate