title: Time course of peri-implant bone regeneration around loaded and unloaded implants in a rat model.
abstract: The time-course of cancellous bone regeneration surrounding mechanically loaded implants affects implant fixation, and is relevant to determining optimal rehabilitation protocols following orthopaedic surgeries. We investigated the influence of controlled mechanical loading of titanium-coated polyether-ether ketone (PEEK) implants on osseointegration using time-lapsed, non-invasive, in vivo micro-computed tomography (micro-CT) scans. Implants were inserted into proximal tibial metaphyses of both limbs of eight female Sprague-Dawley rats. External cyclic loading (60 or 100 μm displacement, 1 Hz, 60 s) was applied every other day for 14 days to one implant in each rat, while implants in contralateral limbs served as the unloaded controls. Hind limbs were imaged with high-resolution micro-CT (12.5 μm voxel size) at 2, 5, 9, and 12 days post-surgery. Trabecular changes over time were detected by 3D image registration allowing for measurements of bone-formation rate (BFR) and bone-resorption rate (BRR). At day 9, mean %BV/TV for loaded and unloaded limbs were 35.5 ± 10.0% and 37.2 ± 10.0%, respectively, and demonstrated significant increases in bone volume compared to day 2. BRR increased significantly after day 9. No significant differences between bone volumes, BFR, and BRR were detected due to implant loading. Although not reaching significance (p = 0.16), an average 119% increase in pull-out strength was measured in the loaded implants. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:997-1006, 2017.
authors.affiliation: Division of Musculoskeletal Sciences, Department of Orthopedics and Rehabilitation, College of Medicine, Pennsylvania State University, 500 University Drive, Hershey 17033, Pennsylvania.
authors.forename: Shailly H
authors.initials: SH
authors.lastname: Jariwala
authors.affiliation: Division of Musculoskeletal Sciences, Department of Orthopedics and Rehabilitation, College of Medicine, Pennsylvania State University, 500 University Drive, Hershey 17033, Pennsylvania.
authors.forename: Hwabok
authors.initials: H
authors.lastname: Wee
authors.affiliation: Division of Musculoskeletal Sciences, Department of Orthopedics and Rehabilitation, College of Medicine, Pennsylvania State University, 500 University Drive, Hershey 17033, Pennsylvania.
authors.forename: Evan P
authors.initials: EP
authors.lastname: Roush
authors.affiliation: Department of Comparative Medicine, Pennsylvania State University College of Medicine, Hershey 17033, Pennsylvania.
authors.forename: Tiffany L
authors.initials: TL
authors.lastname: Whitcomb
authors.affiliation: Division of Musculoskeletal Sciences, Department of Orthopedics and Rehabilitation, College of Medicine, Pennsylvania State University, 500 University Drive, Hershey 17033, Pennsylvania.
authors.forename: Christopher
authors.initials: C
authors.lastname: Murter
authors.affiliation: Division of Musculoskeletal Sciences, Department of Orthopedics and Rehabilitation, College of Medicine, Pennsylvania State University, 500 University Drive, Hershey 17033, Pennsylvania.
authors.forename: Gery
authors.initials: G
authors.lastname: Kozlansky
authors.affiliation: Department of Engineering Science and Mechanics, Pennsylvania State University, University Park 16802-6812, Pennsylvania.
authors.forename: Akhlesh
authors.initials: A
authors.lastname: Lakhtakia
authors.affiliation: Department of Public Health Sciences, Pennsylvania State University College of Medicine, Hershey 17033, Pennsylvania.
authors.forename: Allen R
authors.initials: AR
authors.lastname: Kunselman
authors.affiliation: Department of Biomedical Engineering, Virginia Commonwealth University, Richmond 23284, Virginia.
authors.forename: Henry J
authors.initials: HJ
authors.lastname: Donahue
authors.affiliation: Division of Musculoskeletal Sciences, Department of Orthopedics and Rehabilitation, College of Medicine, Pennsylvania State University, 500 University Drive, Hershey 17033, Pennsylvania.
authors.forename: April D
authors.initials: AD
authors.lastname: Armstrong
authors.affiliation: Division of Musculoskeletal Sciences, Department of Orthopedics and Rehabilitation, College of Medicine, Pennsylvania State University, 500 University Drive, Hershey 17033, Pennsylvania.
authors.forename: Gregory S
authors.initials: GS
authors.lastname: Lewis
mesh_terms: D000818:Animals; D000069343:Bone-Implant Interface / Q000000981:diagnostic imaging*; D021621:Imaging, Three-Dimensional; D023421:Models, Animal; D016348:Osseointegration; D051381:Rats; D017207:Rats, Sprague-Dawley; D016474:Weight-Bearing; D055114:X-Ray Microtomography / Q000379:methods*
keywords: bone remodeling; image registration; implant fixation; mechanical loading; micro-computed tomography