Active Materials for 3D Printing in Small Animals: Current Modalities and Future Directions for Orthopedic Applications

Abstract

The successful clinical application of bone tissue engineering requires customized implants based on the receiver's bone anatomy and defect characteristics. Three-dimensional (3D) printing in small animal orthopedics has recently emerged as a valuable approach in fabricating individualized implants for receiver-specific needs. In veterinary medicine, because of the wide range of dimensions and anatomical variances, receiver-specific diagnosis and therapy are even more critical. The ability to generate 3D anatomical models and customize orthopedic instruments, implants, and scaffolds are advantages of 3D printing in small animal orthopedics. Furthermore, this technology provides veterinary medicine with a powerful tool that improves performance, precision, and cost-effectiveness. Nonetheless, the individualized 3D-printed implants have benefited several complex orthopedic procedures in small animals, including joint replacement surgeries, critical size bone defects, tibial tuberosity advancement, patellar groove replacement, limb-sparing surgeries, and other complex orthopedic procedures. The main purpose of this review is to discuss the application of 3D printing in small animal orthopedics based on already published papers as well as the techniques and materials used to fabricate 3D-printed objects. Finally, the advantages, current limitations, and future directions of 3D printing in small animal orthopedics have been addressed.

Keywords: 3D printing; materials; orthopedics; receiver-specific; veterinary.

Figure 1

Steps for a 3D-printed project.

Figure 2

Receiver-specific approach in a 1.5-year-old Doberman with lateral patellar luxation due to complex angular limb deformity involving valgus and internal torsion of the right femur (a), radiographs). The steps consist of (b) image acquisition in DICOM from CT scans; (c) image processing including 3D reconstruction and volume rendering with Meshmixer software, and (d) 3D printing of anatomical models of both femurs using FFF technique from PLA filaments on a Delta WASP 2040 INDUSTRIAL X 3D Printer (WASP, Massa Lombarda, Ravenna, Italy). CT images and their 3D reconstruction were used to measure angular limb deformity and plan for corrective ostectomy. Models were used for studying the receiver’s anatomy, for surgical rehearsal, and for pre-contouring of the plate before actual surgery. (e) Using 3D modeling, medial closing wedge ostectomy and torsional correction were performed more precisely.

Figure 3

(a) Three-dimensional printing of silicone-based scaffold using DIW; (b) detail of 3D-printing process in an oil bath; (c) morphology of ceramic 3D-printed scaffolds from different views and high magnification detail of a rod fracture surface; (d) MSCs therapy steps include retrieval of adipose tissue from healthy dogs, isolation and characterization of cAD-MSCs, pelleting and seeding the cAD-MS on scaffolds, and its potential in vivo or in clinical applications; (e) cAD-MSCs pelleted and seeded onto the carbon-based scaffolds. SEM images of cAD-MSCs 7 days after culture on carbon-based scaffolds at magnifications of (f) 100× and (g) 5000× reveal significant secretome activity of the cell surfaces on the carbon-based scaffolds. (a–c) copyright 2022, IOP Publishing; (e–g) [6].

Figure 4

Summary of application of 3D printing in veterinary orthopedics.

Figure 5

Custom-designed hemipelvic and proximal femoral endoprosthesis for limb salvage technique in a dog (A), custom-made tantalum distal radial endoprosthesis for limb sparing surgery in a dog (B), virtual planning (C, left) and custom-made 3D printed SLA models, osteotomy guide, reduction guide, and titanium plate (C, right) for correction of antebrachial limb deformity in a dog. (D) custom-made titanium implant for limb sparing surgery in a dog with distal radial OSA. Copy right 2022, (A) BLACKWELLPUBLISHING, INC., (B) Canadian Veterinary Medical Association, (C) Georg Thieme Verlag KG, (D) Daehanuiyongsaengchegonghakoe.