Segmental bone defects caused by tumor resections, trauma, and skeletal abnormalities such as osteomyelitis remain a major problem in orthopedics because of the lack of predictability in attaining functional bone after the treatment. The objective of this study was to propose an indigenous porous biodegradable triphasic ceramic (calcium silicate, tricalcium phosphate, and hydroxyapatite [HA])-coated HA (core) (HASi) for the repair of such segmental defects. With respect to the synthesis of HASi, HA blocks were prepared by wet precipitation, dipped in silica sol (sol gel method), sintered at 1200°C, polished in the form of hollow cylinder (2 cm long with an outer and inner diameter of 2 cm and 7 mm, respectively), and implanted into a 2-cm segmental defect created in the goat femur diaphysis. This study prolonged for 12 uneventful months and thereafter neo-osteogenesis in par with material degradation was analyzed through radiography, histology, histomorphometry, scanning electron microscope (SEM)-energy dispersive spectrum, micro-computed tomography, and inductively coupled plasma spectrometry. HASi proved to be osteoconductive, osteointegrative, and degradative in nature, without the intervention of fibrous tissue formation at the defect site. Histologically, the newly formed bone reorganized, mineralized, and attained the appearance and contour of the original femoral diaphysis in 1 year. The interconnected porous structure with silica composition aided progressive bone regeneration and repair in par with degradation of the material. Thus the study proposed the possibility of using HASi as a suitable material in clinical orthopedic reconstructive surgery, which remains a formidable challenge.
Dr. Manitha B. Nair, Varma, H., Shenoy, S. J., and John, A., “Treatment of Goat Femur Segmental Defects with Silica-Coated Hydroxyapatite—One-Year Follow-Up”, Tissue Engineering Part A, vol. 16, no. 2, pp. 385-391, 2009.