OBJECTIVE Large cartilage defects and osteoarthritis (OA) cause cartilage loss and remain a therapeutic challenge. Three-dimensional (3D) bioprinting with autologous cells using a computer-aided design (CAD) model generated from 3D imaging has the potential to reconstruct patient-specific features that match an articular joint lesion. DESIGN To scan a human OA tibial plateau with a cartilage defect, retrieved after total knee arthroplasty, following clinical imaging techniques were used: (1) computed tomography (CT), (2) magnetic resonance imaging (MRI), and (3) a 3D scanner. From such a scan, a CAD file was obtained to generate G-code to control 3D bioprinting in situ directly into the tibial plateau lesion. RESULTS Highest resolution was obtained using the 3D scanner (2.77 times more points/mm2 than CT), and of the 3 devices tested, only the 3D scanner was able to detect the actual OA defect area. Human chondrocytes included in 3D bioprinted constructs produced extracellular matrix and formed cartilage tissue fragments after 2 weeks of differentiation and high levels of a mature splice version of collagen type II (Col IIA type B), characteristic of native articular cartilage and aggrecan (ACAN). Chondrocytes had a mean viability of 81% in prints after day 5 of differentiation toward cartilage and similar viability was detected in control 3D pellet differentiation of chondrocytes (mean viability 72%). CONCLUSION Articular cartilage can be formed in 3D bioprints. Thus, this 3D bioprinting system with chondrocytes simulating a patient-specific 3D model provides an attractive strategy for future treatments of cartilage defects or early OA.

中文翻译：

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3D 生物打印软骨细胞原位进入骨关节炎软骨胫骨病变后的胶原 2A B 型诱导。

目的 大软骨缺损和骨关节炎 (OA) 会导致软骨丢失，并且仍然是治疗方面的挑战。使用从 3D 成像生成的计算机辅助设计 (CAD) 模型对自体细胞进行 3D (3D) 生物打印具有重建与关节病变匹配的患者特定特征的潜力。设计 为了扫描具有软骨缺损的人类 OA 胫骨平台，在全膝关节置换术后取回，使用了以下临床成像技术：(1) 计算机断层扫描 (CT)，(2) 磁共振成像 (MRI)，和 (3) 3D扫描仪。通过这样的扫描，获得了一个 CAD 文件以生成 G 代码，以控制原位 3D 生物打印直接进入胫骨平台病变。结果 使用 3D 扫描仪获得了最高分辨率（点数/mm2 是 CT 的 2.77 倍），并且在测试的 3 个设备中，只有 3D 扫描仪能够检测到实际的 OA 缺陷区域。包含在 3D 生物打印构建体中的人类软骨细胞在分化 2 周后产生细胞外基质并形成软骨组织碎片，并且具有高水平的成熟剪接版本的 II 型胶原蛋白（Col IIA B 型），这是天然关节软骨和蛋白聚糖 (ACAN) 的特征。在向软骨分化的第 5 天后，软骨细胞的平均存活率为 81%，并且在软骨细胞的对照 3D 颗粒分化中检测到类似的存活率（平均存活率为 72%）。结论 关节软骨可以在 3D 生物打印中形成。因此，这种具有模拟患者特定 3D 模型的软骨细胞的 3D 生物打印系统为未来治疗软骨缺损或早期 OA 提供了一种有吸引力的策略。