Background:Osteochondral allograft (OCA) transplantation is an important surgical technique for full-thickness chondral defects in the knee. For patients undergoing this procedure, topography matching between the donor and recipient sites is essential to limit premature wear of the OCA. Currently, there is no standardized process of donor and recipient graft matching.Purpose:To evaluate a novel topography matching technique for distal femoral condyle OCA transplantation using 3-dimensional (3D) laser scanning to create 3D-printed patient-specific instrumentation in a human cadaveric model.Study Design:Descriptive laboratory study.Methods:Human cadaveric distal femoral condyles (n = 12) underwent 3D laser scanning. An 18-mm circular osteochondral recipient defect was virtually created on the medial femoral condyle (MFC), and the position and orientation of the best topography-matched osteochondral graft from a paired donor lateral femoral condyle (LFC) were determined using an in silico analysis algorithm minimizing articular step-off distances between the edges of the graft and recipient defect. Distances between the entire surface of the OCA graft and the underneath surface of the MFC were evaluated as surface mismatch. Donor (LFC) and recipient (MFC) 3D-printed patient-specific guides were created based on 3D reconstructions of the scanned condyles. Through use of the guides, OCAs were harvested from the LFC and transplanted to the reamed recipient defect site (MFC). The post-OCA recipient condyles were laser scanned. The 360° articular step-off and cartilage topography mismatch were measured.Results:The mean cartilage step-off and graft surface mismatch for the in silico OCA transplant were 0.073 ± 0.029 mm (range, 0.005-0.113 mm) and 0.166 ± 0.039 mm (range, 0.120-0.243 mm), respectively. Comparatively, the cadaveric specimens postimplant had significantly larger step-off differences (0.173 ± 0.085 mm; range, 0.082-0.399 mm; P = .001) but equivalent graft surface topography matching (0.181 ± 0.080 mm; range, 0.087-0.396 mm; P = .678). All 12 OCA transplants had mean circumferential step-off differences less than a clinically significant cutoff of 0.5 mm.Conclusion:These findings suggest that the use of 3D-printed patient-specific guides for OCA transplantation has the ability to reliably optimize cartilage topography matching for LFC to MFC transplantation. This study demonstrated substantially lower step-off values compared with previous orthopaedic literature when also evaluating LFC to MFC transplantation. Using this novel technique in a model performing MFC to MFC transplantation has the potential to yield further enhanced results due to improved radii of curvature matching.Clinical Relevance:Topography-matched graft implantation for focal chondral defects of the knee in patients improves surface matching and has the potential to improve long-term outcomes. Efficient selection of the allograft also allows improved availability of the limited allograft sources.

中文翻译：

---

患者特异性远端股骨导板可优化同种异体骨软骨移植中的软骨地形匹配


背景：同种异体骨软骨移植（OCA）移植是治疗膝关节全层软骨缺损的重要手术技术。对于接受此手术的患者来说，供体和受体部位之间的地形匹配对于限制 OCA 的过早磨损至关重要。目前，尚无供体和受体移植物匹配的标准化流程。目的：评估一种用于股骨远端髁 OCA 移植的新型地形匹配技术，使用 3 维 (3D) 激光扫描在人体中创建 3D 打印的患者专用器械尸体模型。研究设计：描述性实验室研究。方法：对人体尸体股骨远端髁 (n = 12) 进行 3D 激光扫描。在股骨内侧髁 (MFC) 上虚拟创建 18 毫米圆形骨软骨受体缺损，并使用计算机分析确定来自配对供体股骨外侧髁 (LFC) 的最佳地形匹配骨软骨移植物的位置和方向算法最小化移植物边缘和受体缺损边缘之间的关节步距。 OCA 移植物的整个表面与 MFC 下表面之间的距离被评估为表面失配。供体 (LFC) 和受体 (MFC) 3D 打印的患者特定导板是根据扫描髁突的 3D 重建创建的。通过使用导向器，从 LFC 中收获 OCA 并将其移植到扩孔的受体缺损部位 (MFC)。对 OCA 后受体髁进行激光扫描。测量了 360° 关节步距和软骨地形失配。结果：计算机 OCA 移植的平均软骨步距和移植物表面失配分别为 0.073 ± 0.029 mm（范围，0.005-0.113 mm）和 0.166 ± 0.039 mm （范围，0.120-0.243 毫米），分别。相比之下，移植后尸体标本的步距差异显着更大（0.173 ± 0.085 mm；范围，0.082-0.399 mm；P = .001），但移植物表面形貌匹配相当（0.181 ± 0.080 mm；范围，0.087-0.396 mm；范围，0.087-0.396 mm； P = .678）。所有 12 例 OCA 移植的平均周向步距差异均小于 0.5 毫米的临床显着截止值。结论：这些研究结果表明，使用 3D 打印的 OCA 移植患者特异性指南能够可靠地优化软骨地形匹配，以实现 OCA 移植。 LFC到MFC的移植。这项研究表明，在评估 LFC 至 MFC 移植时，与之前的骨科文献相比，步距值要低得多。在执行 MFC 至 MFC 移植的模型中使用这项新技术，由于曲率半径匹配的改善，有可能产生进一步增强的结果。临床相关性：针对患者膝关节局灶性软骨缺损的地形匹配移植物植入改善了表面匹配，并具有改善长期成果的潜力。同种异体移植物的有效选择还可以提高有限同种异体移植物来源的可用性。