Al Ramlawi Akram, Nahm Nickolas, Abdou Michael, Salem Hytham S, Herzenberg John E, McClure Philip
Department of Orthopedics, LifeBridge Health, International Center for Limb Lengthening, Sinai Hospital of Baltimore, Rubin Institute for Advanced Orthopedics, 2401 West Belvedere Avenue, Baltimore, MD, 21215, USA.
Department of Orthopedics, Gillette Children's Specialty Healthcare, Saint Paul, MN, USA.
Skeletal Radiol. 2025 Feb 1. doi: 10.1007/s00256-025-04879-5.
Accurate limb length measurement is essential during limb lengthening procedures to prevent neurologic and musculoskeletal complications. Magnetic intramedullary lengthening nails (MILN) rely on radiographs for measurement, but the optimal radiographic technique is not established. This study evaluated the precision and accuracy of EOS imaging versus digital radiography, including calibration techniques and measurement techniques for assessing intramedullary lengthening.
An MILN was inserted into a Sawbones femur, and lengthening measurements from digital X-ray and EOS imaging were compared to external remote control (ERC) results. Measurements were taken with and without calibration using a magnification ball, nail width, or female nail length. Four observers measured the distraction gap, spindle length, full nail length, and male nail length at various hip flexion angles. Precision and accuracy were calculated for each technique.
From 576 measurements, EOS imaging demonstrated significantly higher accuracy than digital radiography (83.6% vs. 73.5% absolute accuracy; p < 0.001) when non-calibrated values were included. EOS maintained superior accuracy at 30 mm, 50 mm, and 70 mm of lengthening (p < 0.05), with no difference at 10 mm. Calibration did not affect EOS accuracy, whereas digital radiography was less accurate without calibration (p < 0.001). Distraction gap measurement was the most accurate for both modalities, and 0° hip flexion provided the highest precision. Overall, EOS was more precise (79.4% vs. 71.7% precision rates; p < 0.001).
EOS imaging is recommended for limb lengthening measurements due to its superior precision and accuracy. For digital radiographs, careful calibration is essential to achieve accurate measurements.
在肢体延长手术过程中，准确测量肢体长度对于预防神经和肌肉骨骼并发症至关重要。磁性髓内延长钉（MILN）依靠X线片进行测量，但最佳的X线摄影技术尚未确立。本研究评估了EOS成像与数字X线摄影的精度和准确性，包括用于评估髓内延长的校准技术和测量技术。
将一枚MILN插入Sawbones股骨模型中，将数字X线和EOS成像的延长测量结果与外部遥控（ERC）结果进行比较。使用放大球、钉宽度或女性钉长度进行校准和未校准的情况下进行测量。四名观察者在不同的髋关节屈曲角度测量牵张间隙、纺锤体长度、全钉长度和男性钉长度。计算每种技术的精度和准确性。
在576次测量中，当纳入未校准值时，EOS成像显示出比数字X线摄影显著更高的准确性（绝对准确性分别为83.6%和73.5%；p<0.001）。在延长30mm、50mm和70mm时，EOS保持了更高的准确性（p<0.05），在10mm时无差异。校准不影响EOS的准确性，而数字X线摄影在未校准时准确性较低（p<0.001）。对于两种方式，牵张间隙测量最准确，髋关节屈曲0°时精度最高。总体而言，EOS更精确（精度率分别为79.4%和71.7%；p<0.001）。
由于EOS成像具有更高的精度和准确性，因此推荐用于肢体延长测量。对于数字X线片，仔细校准对于获得准确测量结果至关重要。
