AccScience Publishing / IJB / Online First / DOI: 10.36922/ijb.8115
RESEARCH ARTICLE
Early Access

Enhancing bone ingrowth and mechanical bond strength at the titanium alloy 3D-printed implant-bone interface through advanced lattice designs and growth factor integration

Yu-San Chen1 Po-Kuei Wu2,3 Wei-Che Tsai1 Chun-Li Lin1,4*
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1 Department of Biomedical Engineering, National Yang Ming Chaio Tung University, Hsinchu, Taiwan
2 Department of Orthopaedics, Therapeutical and Research Center of Musculoskeletal Tumor, Taipei Veterans General Hospital, Taipei 112, Taiwan
3 Orthopaedic Department School of Medicine, National Yang Ming Chiao Tung University, Taipei 112, Taiwan
4 Medical Device Innovation & Translation Center, National Yang Ming Chiao Tung University, Hsinchu, Taiwan
Submitted: 21 December 2024 | Accepted: 6 February 2025 | Published: 6 February 2025
© 2025 by the Author(s). This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution 4.0 International License ( https://creativecommons.org/licenses/by/4.0/ )
Abstract

Patient-specific titanium alloy 3D-printed implants often face challenges such as stress shielding and insufficient osseointegration. This study investigated the effects of lattice designs and growth factor-enriched sticky bone on bone ingrowth and mechanical bond strength at the implant-bone interface of the large-scale bone defect at distal femur condyle of New Zealand rabbit model. Hollow cylindrical implants (12 mm length, 6 mm outer, 2 mm inner diameters) with diamond (DU) and randomly deformed spherical (YMR) lattices were designed and implanted into rabbit femoral condyles. Platelet-rich fibrin (PRF) was prepared using a novel negative pressure centrifuge and mixed with synthetic bone graft material to form sticky bone, which was used to fill the implant cavities. Micro-CT imaging assessed bone ingrowth volume across zones, while mechanical testing evaluated shear bond strength. The results demonstrated that growth factors were the primary driver of bone ingrowth and mechanical strength. Bone growth volume increased significantly in Zone A (implant cavity), with sticky bone yielding a 6.9-fold increase for DU (6.66 mm³ vs. 45.89 mm³) and a 3.5-fold increase for YMR (14.68 mm³ vs. 51.95 mm³). Across Zones B and C (lattice layers), YMR lattices consistently outperformed DU in promoting bone growth and stability. Push-out tests showed shear bond strengths of 2.78 MPa for DU and 2.83 MPa for YMR with growth factors, compared to 1.71 MPa for controls. This study highlights the critical role of growth factors in enhancing bone integration and demonstrates the complementary benefits of optimized lattice designs, particularly YMR, in improving osseointegration and mechanical stability. The findings provide a promising strategy for using 3D-printed titanium alloy implants with sticky bone systems to address large bone defects in clinical applications.

Keywords
3D printing
Bone defect
Lattice
Growth factor
Platelet-rich fibrin
Funding
This study is supported in part by NSTC project 112-2221-E-A49 -009 -MY3 and 113-2811-B-A49A-061, Taiwan
Conflict of interest
No potential conflict of interest was reported by the author(s)
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International Journal of Bioprinting, Electronic ISSN: 2424-8002 Print ISSN: 2424-7723, Published by AccScience Publishing