title: Effect of pore size on bone ingrowth into porous titanium implants fabricated by additive manufacturing: An in vivo experiment.
abstract: Selective laser melting (SLM) is an additive manufacturing technique with the ability to produce metallic scaffolds with accurately controlled pore size, porosity, and interconnectivity for orthopedic applications. However, the optimal pore structure of porous titanium manufactured by SLM remains unclear. In this study, we evaluated the effect of pore size with constant porosity on in vivo bone ingrowth in rabbits into porous titanium implants manufactured by SLM. Three porous titanium implants (with an intended porosity of 65% and pore sizes of 300, 600, and 900μm, designated the P300, P600, and P900 implants, respectively) were manufactured by SLM. A diamond lattice was adapted as the basic structure. Their porous structures were evaluated and verified using microfocus X-ray computed tomography. Their bone-implant fixation ability was evaluated by their implantation as porous-surfaced titanium plates into the cortical bone of the rabbit tibia. Bone ingrowth was evaluated by their implantation as cylindrical porous titanium implants into the cancellous bone of the rabbit femur for 2, 4, and 8weeks. The average pore sizes of the P300, P600, and P900 implants were 309, 632, and 956μm, respectively. The P600 implant demonstrated a significantly higher fixation ability at 2weeks than the other implants. After 4weeks, all models had sufficiently high fixation ability in a detaching test. Bone ingrowth into the P300 implant was lower than into the other implants at 4weeks. Because of its appropriate mechanical strength, high fixation ability, and rapid bone ingrowth, our results indicate that the pore structure of the P600 implant is a suitable porous structure for orthopedic implants manufactured by SLM.
authors.affiliation: Department of Orthopaedic Surgery, Kyoto University Graduate School of Medicine, 54 Kawahara-cho, Shogoin, Sakyo, Kyoto 606-8507, Japan. Electronic address: tani110@kuhp.kyoto-u.ac.jp.
authors.forename: Naoya
authors.initials: N
authors.lastname: Taniguchi
authors.affiliation: Department of Orthopaedic Surgery, Kyoto University Graduate School of Medicine, 54 Kawahara-cho, Shogoin, Sakyo, Kyoto 606-8507, Japan. Electronic address: shfuji@kuhp.kyoto-u.ac.jp.
authors.forename: Shunsuke
authors.initials: S
authors.lastname: Fujibayashi
authors.affiliation: Department of Orthopaedic Surgery, Kyoto University Graduate School of Medicine, 54 Kawahara-cho, Shogoin, Sakyo, Kyoto 606-8507, Japan. Electronic address: m.take@kuhp.kyoto-u.ac.jp.
authors.forename: Mitsuru
authors.initials: M
authors.lastname: Takemoto
authors.affiliation: Sagawa Printing Co., Ltd., 5-3, Inui, Morimoto-Cho, Mukou-Shi, Kyoto 617-8588, Japan. Electronic address: kiy-sasaki@spcom.co.jp.
authors.forename: Kiyoyuki
authors.initials: K
authors.lastname: Sasaki
authors.affiliation: Department of Orthopaedic Surgery, Kyoto University Graduate School of Medicine, 54 Kawahara-cho, Shogoin, Sakyo, Kyoto 606-8507, Japan. Electronic address: bungo@kuhp.kyoto-u.ac.jp.
authors.forename: Bungo
authors.initials: B
authors.lastname: Otsuki
authors.affiliation: National Hospital Organization Kyoto Medical Center, 1-1, Mukaihatacho, Hukakusa, Hushimi, Kyoto 612-8555, Japan. Electronic address: ntaka@kuhp.kyoto-u.ac.jp.
authors.forename: Takashi
authors.initials: T
authors.lastname: Nakamura
authors.affiliation: Department of Biomedical Sciences, College of Life and Health Sciences, Chubu University, 1200 Matsumoto-cho, Kasugai, Aichi 487-8501, Japan. Electronic address: matsushi@isc.chubu.ac.jp.
authors.forename: Tomiharu
authors.initials: T
authors.lastname: Matsushita
authors.affiliation: Department of Biomedical Sciences, College of Life and Health Sciences, Chubu University, 1200 Matsumoto-cho, Kasugai, Aichi 487-8501, Japan. Electronic address: kokubo@isc.chubu.ac.jp.
authors.forename: Tadashi
authors.initials: T
authors.lastname: Kokubo
authors.affiliation: Department of Orthopaedic Surgery, Kyoto University Graduate School of Medicine, 54 Kawahara-cho, Shogoin, Sakyo, Kyoto 606-8507, Japan. Electronic address: smat522@kuhp.kyoto-u.ac.jp.
authors.forename: Shuichi
authors.initials: S
authors.lastname: Matsuda
mesh_terms: D000818:Animals; D018786:Bone Substitutes / Q000737:chemistry / Q000494:pharmacology; D020007:Implants, Experimental; D008422:Materials Testing; D016062:Porosity; D011817:Rabbits; D013977:Tibia / Q000378:metabolism / Q000473:pathology; D014025:Titanium / Q000737:chemistry / Q000494:pharmacology
chemical_list: D018786:Bone Substitutes; D014025:Titanium
keywords: Additive manufacturing; Bone ingrowth; Pore size; Porous titanium; Selective laser melting