Orthopaedic Research Unit, Department of Orthopaedic Surgery and Traumatology, Odense University Hospital, Odense, Denmark; Department of Clinical Research, University of Southern Denmark, Odense, Denmark
Orthopaedic Research Unit, Department of Orthopaedic Surgery and Traumatology, Odense University Hospital, Odense, Denmark; Department of Clinical Research, University of Southern Denmark, Odense, Denmark.
Acta Orthop. 2024 Sep 13;95:530-535. doi: 10.2340/17453674.2024.41912.
The low-dose EOS Imaging System is an emerging tool for 3-dimensional measurements in orthopedics. The clinical feasibility for measuring total hip arthroplasty (THA) liner wear has not yet been investigated. We aimed to evaluate the feasibility of using EOS to measure THA liner wear by examining the experimental accuracy using a THA phantom and clinical precision of patients with THA, considering a clinically relevant precision at the 95% repeatability limit to be 0.2 mm.
An experimental THA phantom with movable stem and a fixed cup with a plastic liner was constructed to simulate progressive 3D liner wear. Series of 11 pairs of radiographs with 50 μm femoral movement in between were obtained for each 3D axis in EOS. 30 patients with a THA were scanned twice using EOS to assess precision. Model-based radiostereometric analysis (RSA) was used for wear measurement.
The mean difference (true minus simulated wear) with standard deviation (SD) and 95% limits of agreement for experimental THA wear were 0.005 (0.037) and [-0.069 to 0.079] mm for the vertical (y) axis. The mean (SD) and 95% repeatability limit for precision for clinical measurement were -0.029 (0.105) and 0.218 mm.
Experimental THA liner wear using EOS was within clinically relevant tolerances and without bias. The clinical precision was just outside our defined clinically relevant precision. Compared with conventional RSA, EOS is less accurate and precise but may still be of value for certain clinical applications, provided larger sample size or longer follow-up are available.
低剂量 EOS 成像系统是一种新兴的三维测量工具，用于骨科。尚未研究其在测量全髋关节置换术（THA）衬垫磨损方面的临床可行性。我们旨在通过检查使用 THA 模型进行的实验准确性和 THA 患者的临床精度来评估 EOS 测量 THA 衬垫磨损的可行性，考虑到在 95%可重复性限下具有临床相关性的精度为 0.2 毫米。
构建了一个具有可移动柄和固定杯的塑料衬垫的实验性 THA 模型，以模拟渐进性 3D 衬垫磨损。在 EOS 中，对于每个 3D 轴，获得了 11 对带有 50μm 股骨移动的射线照片系列。使用 EOS 对 30 例 THA 患者进行了两次扫描，以评估精度。使用基于模型的放射立体测量分析（RSA）进行磨损测量。
实验性 THA 磨损的真实值减去模拟值的平均值（标准差 [SD]）和 95%一致性限为 0.005（0.037）和[-0.069 至 0.079]mm，用于 y 轴（垂直轴）。临床测量精度的平均值（SD）和 95%可重复性限为-0.029（0.105）和 0.218mm。
EOS 测量的实验性 THA 衬垫磨损在临床相关的容差范围内，且无偏差。临床精度刚好超出我们定义的具有临床相关性的精度。与传统 RSA 相比，EOS 的准确性和精度较低，但在具有更大样本量或更长随访时间的情况下，EOS 可能仍具有一定的临床应用价值。
