Daugaard H, Elmengaard B, Andreassen T T, Baas J, Bechtold J E, Soballe K
Department of Orthopaedic Surgery, Orthopaedic Research Laboratory, Aarhus University Hospital, Norrebrogade 44, Building 1A, DK-8000 Aarhus C, Denmark.
J Bone Joint Surg Br. 2011 Jan;93(1):131-9. doi: 10.1302/0301-620X.93B1.24261.
Impaction allograft is an established method of securing initial stability of an implant in arthroplasty. Subsequent bone integration can be prolonged, and the volume of allograft may not be maintained. Intermittent administration of parathyroid hormone has an anabolic effect on bone and may therefore improve integration of an implant. Using a canine implant model we tested the hypothesis that administration of parathyroid hormone may improve osseointegration of implants surrounded by bone graft. In 20 dogs a cylindrical porous-coated titanium alloy implant was inserted into normal cancellous bone in the proximal humerus and surrounded by a circumferential gap of 2.5 mm. Morsellised allograft was impacted around the implant. Half of the animals were given daily injections of human parathyroid hormone (1-34) 5 μg/kg for four weeks and half received control injections. The two groups were compared by mechanical testing and histomorphometry. We observed a significant increase in new bone formation within the bone graft in the parathyroid hormone group. There were no significant differences in the volume of allograft, bone-implant contact or in the mechanical parameters. These findings suggest that parathyroid hormone improves new bone formation in impacted morsellised allograft around an implant and retains the graft volume without significant resorption. Fixation of the implant was neither improved nor compromised at the final follow-up of four weeks.
嵌压式同种异体骨移植是在关节置换术中确保植入物初始稳定性的一种既定方法。后续的骨整合可能会延长，且同种异体骨的体积可能无法维持。间歇性给予甲状旁腺激素对骨骼有合成代谢作用，因此可能会改善植入物的整合。我们使用犬类植入模型检验了甲状旁腺激素给药可能会改善被骨移植包围的植入物骨整合的假设。在20只犬中，将圆柱形多孔涂层钛合金植入物插入肱骨近端的正常松质骨中，并在其周围留出2.5毫米的圆周间隙。将粉碎的同种异体骨嵌压在植入物周围。一半动物每天注射5μg/kg的人甲状旁腺激素（1-34），持续四周，另一半接受对照注射。通过力学测试和组织形态计量学对两组进行比较。我们观察到甲状旁腺激素组骨移植内新骨形成显著增加。在同种异体骨体积、骨与植入物接触或力学参数方面没有显著差异。这些发现表明，甲状旁腺激素可改善植入物周围嵌压粉碎同种异体骨中的新骨形成，并保持移植骨体积，无明显吸收。在四周的最终随访中，植入物的固定既未改善也未受损。
