In vitro and in vivo study of additive manufactured porous Ti6Al4V scaffolds for repairing bone defects

Abstract

Metallic implants with a low effective modulus can provide early load-bearing and reduce stress shielding, which is favorable for increasing in vivo life-span. In this research, porous Ti6Al4V scaffolds with three pore sizes (300~400, 400~500, and 500~700 μm) were manufactured by Electron Beam Melting, with an elastic modulus range of 3.7 to 1.7 GPa. Cytocompatibility in vitro and osseointegration ability in vivo of scaffolds were assessed. hBMSCs numbers increased on all porous scaffolds over time. The group with intended pore sizes of 300 to 400 μm was significantly higher than that of the other two porous scaffolds at days 5 and 7. This group also had higher ALP activity at day 7 in osteogenic differentiation experiment. The scaffold with pore size of 300 to 400 μm was implanted into a 30-mm segmental defect of goat metatarsus. In vivo evaluations indicated that the depth of bone ingrowth increased over time and no implant dislocation occurred during the experiment. Based on its better cytocompatibility and favorable bone ingrowth, the present data showed the capability of the additive manufactured porous Ti6Al4V scaffold with an intended pore size of 300 to 400 μm for large segmental bone defects.

Hot isostatic pressure treatment of 3D printed Ti6Al4V alters surface modifications and cellular response

“…Pore size and porosity have been shown to alter the degree of osseointegration of porous implants in vivo and in vitro cellular response. Studies examining varying pore sizes in AM femoral bone defect implants in goats demonstrated an ability for cells to infiltrate and produce new bone at 300–400 μm, while other studies in rabbits have shown that 600 μm pore size enhances osseointegration compared to 300 and 900 μm (Li et al, ; Taniguchi et al, ). These variabilities in outcomes suggest other factors contribute to the osseointegration of a porous implant.…”

“…The addition of biomimetic architecture most likely contributes through altered cytoskeletal reorganization that activates signaling pathways which increase osteoblast response. Previous studies have shown that cytoskeletal reorganization in response to implant surface or cell spanning of pores results in increased production of osteoblast markers (Lai et al, ; Li et al, ; Lo et al, ).…”

“…The specific properties of the pores can also affect outcomes. Studies using a goat femur model have shown that varying pore size can affect early fixation and vascularization (Li et al, ).…”

Mechanical Properties and In Vitro Behavior of Additively Manufactured and Functionally Graded Ti6Al4V Porous Scaffolds

“…One potential the applied stress [24] resulting in differences in the internal structure (porosity and composition) and mechanical properties of the bone along its dimensions. For example, the elastic modulus of trabecular bone at the ends of long bones or within the interior of vertebrae is around 0.5 GPa [25]. This variation in elastic modulus depending on the location in the bone indicates the need for development of gradient structures in bone scaffolds.…”

Three-dimension-printed custom-made prosthetic reconstructions: from revision surgery to oncologic reconstructions

“…None of the commonly used reconstructive techniques has been able to provide optimal results in case of Paprosky 3A and 3B bone defects [18,19]. In the recent years, several Authors have therefore begun to use custom-made 3D-printed prostheses in non-oncologic settings, with encouraging results [15,[20][21][22]. Some Authors reported encouraging results with custom 3D-printed tri-flanged acetabular implants for the management of severe acetabular defects: Taunton et al retrospectively analyzed 57 patients with pelvic discontinuity reporting a stable implant at a mean follow-up of 65 months, despite high incidence of complications [21].…”