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International Journal of Bioprinting 3DP Ta buttress in DDH shelf acetabuloplasty

1. Introduction Research in China. The primary element in its chemical
composition is Ta, with impurity elements at mass
Developmental dysplasia of the hip (DDH) includes a fractions (%): O: 0.030, C: 0.010, N: 0.010, H: 0.0020, Nb:
wide variety of hip joint abnormalities, characterized by 0.050, Fe: 0.010, Ti: 0.005, W: 0.010, Mo: 0.010, Si: 0.005,
incomplete acetabulum coverage of the femoral head. and Ni: 0.010. The Ta1 powder is spherical and exhibits
This often leads to excessive concentration of stress on the following physical properties: particle size: 45–105 μm,
the articular cartilage and labrum, resulting in damage to apparent density ≥9.2 g/cm³, tapped density ≥9.8 g/cm³,
cartilage and labral structures, and eventually osteoarthritis and flowability ≤10 s/50 g.
(OA). Therefore, addressing the pathological changes
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of hip dysplasia involves increasing the coverage area 2.1.2. Patients
of the acetabulum to the femoral head and restoring the Patients with DDH who underwent shelf acetabuloplasty
concentricity of the hip joint, which can effectively prevent using a 3D-printed porous tantalum buttress in our Center
cartilage and labrum damage and slow OA progression. from November 2018 to January 2022 were selected. The
For adolescent and adult patients with DDH, various inclusion criteria were: (i) diagnosis of symptomatic DDH
surgical techniques have been introduced to increase with a lateral center-edge (LCE) angle <20°; (ii) symptoms
acetabular coverage of the femoral head, including lasting for more than 3 months and refractory to
periacetabular osteotomy (PAO) and shelf acetabuloplasty. conservative treatment; (iii) Crowe type I and II; (iv) Tonnis
PAO is time-consuming, highly invasive, and carries a OA grade 0–1; (v) patients voluntarily chose 3D-printed
high risk of injury to critical blood vessels and nerves; porous tantalum buttress in shelf acetabuloplasty. The
postoperative issues, such as unstable reduction and late- exclusion criteria were: (i) patients with a history of
onset nonunion, are common complications. In contrast, previous hip surgery; (ii) patients with immature bones;
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shelf acetabuloplasty is a simple and less invasive procedure (iii) patients with hip joint infection or active infection
that does not worsen the natural progression of OA and at other sites; (iv) patients with other serious diseases or
has a much lower risk of serious complications than PAO. intolerance to surgery on systemic evaluation; (v) patients
However, despite its widespread clinical application, shelf who were allergic to metal implants; and (vi) postoperative
acetabuloplasty still presents several technical limitations. follow-up for less than 12 months.
In this study, we utilized cutting-edge advancements Finally, a total of 21 DDH patients (25 hips,
in 3D printing technology and the promising properties encompassing 18 hips of Crowe type I and 7 hips of Crowe
of tantalum as an ideal bone substitute material. type II) were enrolled, including 6 males and 15 females,
Individualized porous tantalum implants were designed aged 13–39 years, with an average age of 21.38 ± 7.39
and manufactured using 3D preoperative planning years. The average body mass index (BMI) was 21.69 ±
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with a precise fit and optimal positioning, making them 4.23 kg/m , and the duration of symptoms was 37.56 ±
a viable alternative to traditional bone grafts in shelf 30.99 months. All patients complained of hip pain after
acetabuloplasty. This approach aims to address the standing for a long time or walking long distances and
challenges associated with conventional bone implants, limited motor functions (e.g., squatting, running, and
such as difficult implantation, potential positional jumping); three patients had claudication. All patients
deviation, inadequate coverage, and possible long-term received conservative treatment for more than 3 months,
resorption of the graft. Moreover, tantalum’s porous but their symptoms did not improve, affecting their daily
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structure, adequate strength, and elastic modulus provide life and work.
sustained mechanical support while facilitating healing This study was approved by the Ethics Committee of
and the transformation into fibrocartilaginous structures our hospital (No. KY201908), and all patients signed the
in different tissue regions. This improves the accuracy and informed consent form.
efficacy of shelf acetabuloplasty, offering a safer and more
effective treatment option for DDH. 2.2. Design and fabrication of 3D-printed
individualized porous tantalum buttress
2. Materials and methods 2.2.1. Establishment of computer-aided design
2.1. Materials models for DDH
Bilateral hip joints were scanned using the SOMATOM
2.1.1. Tantalum powder Definition CT scanning equipment (SIEMENS, Germany),
The 3D-printed porous tantalum buttress was fabricated with slice thickness and spacing set at 1.0 mm. The scanning
using type I tantalum (Ta1) powder as raw material, range included the entire pelvis and the proximal 15 cm of
sourced from the Northwest Institute for Nonferrous Metal both femurs, with a resolution of 512  512 pixels. The 2D

Volume 10 Issue 6 (2024) 210 doi: 10.36922/ijb.4074