Department of Trauma Surgery, Klinikum rechts der Isar, Technische Universität München, Ismaninger Str. 22, 81675 Munich, Germany.
BMC Musculoskelet Disord. 2012 Mar 9;13:33. doi: 10.1186/1471-2474-13-33.
Fracture-healing depends on interfragmentary motion. For improved osteosynthesis and fracture-healing, the micromotion between fracture fragments is undergoing intensive research. The detection of 3D micromotions at the fracture gap still presents a challenge for conventional tactile measurement systems. Optical measurement systems may be easier to use than conventional systems, but, as yet, cannot guarantee accuracy. The purpose of this study was to validate the optical measurement system PONTOS 5M for use in biomechanical research, including measurement of micromotion.
A standardized transverse fracture model was created to detect interfragmentary motions under axial loadings of up to 200 N. Measurements were performed using the optical measurement system and compared with a conventional high-accuracy tactile system consisting of 3 standard digital dial indicators (1 μm resolution; 5 μm error limit).
We found that the deviation in the mean average motion detection between the systems was at most 5.3 μm, indicating that detection of micromotion was possible with the optical measurement system. Furthermore, we could show two considerable advantages while using the optical measurement system. Only with the optical system interfragmentary motion could be analyzed directly at the fracture gap. Furthermore, the calibration of the optical system could be performed faster, safer and easier than that of the tactile system.
The PONTOS 5 M optical measurement system appears to be a favorable alternative to previously used tactile measurement systems for biomechanical applications. Easy handling, combined with a high accuracy for 3D detection of micromotions (≤ 5 μm), suggests the likelihood of high user acceptance. This study was performed in the context of the deployment of a new implant (dynamic locking screw; Synthes, Oberdorf, Switzerland).
骨折愈合取决于断端间的活动。为了改善内固定和骨折愈合，人们对内固定物周围的微活动进行了深入研究。目前，常规触诊测量系统仍难以检测骨折间隙的三维微活动。相比之下，光学测量系统虽然使用起来可能更为便捷，但目前尚不能保证其准确性。本研究旨在验证 PONTOS 5M 光学测量系统在生物力学研究中的有效性，包括对微活动的测量。
建立了一种标准化的横向骨折模型，用于检测轴向载荷达 200N 时的断端间运动。使用光学测量系统进行测量，并与由 3 个标准数字千分表组成的常规高精度触诊系统（分辨率为 1μm，误差极限为 5μm）进行比较。
我们发现两种系统检测到的平均运动之间的偏差最大为 5.3μm，表明光学测量系统可以检测微活动。此外，在使用光学测量系统时，我们还发现了两个显著的优势。只有使用光学系统才能直接在骨折间隙处分析断端间活动。此外，与触诊系统相比，光学系统的校准更快、更安全、更容易。
PONTOS 5M 光学测量系统似乎是一种优于传统触诊测量系统的生物力学应用替代方案。其易于操作，结合高精度的三维微活动检测（≤5μm），有望获得高度的用户认可。本研究是在一种新型植入物（动力锁定螺钉；Synthes，Oberdorf，瑞士）的应用背景下进行的。
