IDMEC, Instituto Superior Técnico, Universidade de Lisboa, Lisbon, Portugal.
Biofabrication. 2014 Jun;6(2):025005. doi: 10.1088/1758-5082/6/2/025005. Epub 2014 Mar 21.
Fabrication of customized implants based on patient bone defect characteristics is required for successful clinical application of bone tissue engineering. Recently a new surgical procedure, tibial tuberosity advancement (TTA), has been used to treat cranial cruciate ligament (CrCL) deficient stifle joints in dogs, which involves an osteotomy and the use of substitutes to restore the bone. However, limitations in the use of non-biodegradable implants have been reported. To overcome these limitations, this study presents the development of a bioceramic customized cage to treat a large domestic dog assigned for TTA treatment. A cage was designed using a suitable topology optimization methodology in order to maximize its permeability whilst maintaining the structural integrity, and was manufactured using low temperature 3D printing and implanted in a dog. The cage material and structure was adequately characterized prior to implantation and the in vivo response was carefully monitored regarding the biological response and patient limb function. The manufacturing process resulted in a cage composed of brushite, monetite and tricalcium phosphate, and a highly permeable porous morphology. An overall porosity of 59.2% was achieved by the combination of a microporosity of approximately 40% and a designed interconnected macropore network with pore sizes of 845 μm. The mechanical properties were in the range of the trabecular bone although limitations in the cage's reliability and capacity to absorb energy were identified. The dog's limb function was completely restored without patient lameness or any adverse complications and also the local biocompatibility and osteoconductivity were improved. Based on these observations it was possible to conclude that the successful design, fabrication and application of a customized cage for a dog CrCL treatment using a modified TTA technique is a promising method for the future fabrication of patient-specific bone implants, although clinical trials are required.
基于患者骨缺损特征定制植入物是骨组织工程成功临床应用的关键。最近，一种新的手术方法——胫骨结节移位术（TTA）被用于治疗犬的十字韧带（CrCL）缺失的膝关节，该方法涉及截骨和使用替代物来修复骨骼。然而，非生物降解植入物的使用受到限制。为了克服这些限制，本研究提出了一种用于治疗大型犬 TTA 治疗的生物陶瓷定制笼的开发。使用合适的拓扑优化方法设计了一个笼，以最大限度地提高其渗透性，同时保持结构完整性，并使用低温 3D 打印制造并植入犬体内。在植入前对笼材料和结构进行了充分的特性描述，并仔细监测了体内反应，以评估生物反应和患者肢体功能。制造过程产生了一种由 brushite、monetite 和 tricalcium phosphate 组成的笼，具有高度可渗透的多孔形态。通过结合约 40%的微孔和具有 845μm 孔径的设计互连大孔网络，实现了 59.2%的总孔隙率。机械性能处于松质骨的范围内，尽管存在笼的可靠性和能量吸收能力的局限性。犬的肢体功能完全恢复，没有出现跛行或任何不良反应，并且局部生物相容性和骨诱导性也得到了改善。基于这些观察结果，可以得出结论，使用改良的 TTA 技术为犬 CrCL 治疗定制笼的成功设计、制造和应用是未来为患者定制骨植入物制造的一种有前途的方法，尽管还需要进行临床试验。
