Department of Orthopaedics, University of Utah, Salt Lake City, Utah, United States of America.
Department of Biomedical Engineering, University of Utah, Salt Lake City, Utah, United States of America.
PLoS One. 2020 Aug 6;15(8):e0237179. doi: 10.1371/journal.pone.0237179. eCollection 2020.
Percutaneous osseointegrated (OI) implants are increasingly viable as an alternative to socket suspension of prosthetic limbs. Upper extremity prostheses have also become more complex to better replicate hand and arm function and attempt to recreate pre-amputation functional levels. With more functionality comes heavier devices that put more stress on the bone-implant interface, which could be an issue for implant stability. This study quantified transhumeral loading at defined amputation levels using four simulated prosthetic limb-types: (1) body powered hook, (2) myoelectric hook, (3) myoelectric hand, and (4) advanced prosthetic limb. Computational models were constructed to replicate the weight distribution of each prosthesis type, then applied to motion capture data collected during Advanced Activities of Daily Living (AADLs). For activities that did not include a handheld weight, the body powered prosthesis bending moments were 13-33% (range of means for each activity across amputation levels) of the intact arm moments (reference 100%), torsional moments were 12-15%, and axial pullout forces were 30-40% of the intact case (p≤0.001). The myoelectric hook and hand bending moments were 60-99%, torsional moments were 44-97%, and axial pullout forces were 62-101% of the intact case. The advanced prosthesis bending moments were 177-201%, torsional moments were 164-326%, and axial pullout forces were 133-185% of the intact case (p≤0.001). The addition of a handheld weight for briefcase carry and jug lift activities reduced the overall impact of the prosthetic model itself, where the body powered forces and moments were much closer to those of the intact model, and more complex prostheses further increased forces and moments beyond the intact arm levels. These results reveal a ranked order in loading magnitude according to complexity of the prosthetic device, and highlight the importance of considering the patient's desired terminal device when planning post-operative percutaneous OI rehabilitation and training.
经皮骨整合（OI）植入物作为假肢套接悬置的替代方案越来越可行。上肢假肢也变得更加复杂，以更好地复制手和手臂的功能，并试图重新创造截肢前的功能水平。随着功能的增加，设备也变得更重，这会给骨-植入物界面带来更大的压力，这可能成为植入物稳定性的一个问题。本研究使用四种模拟假肢类型，在特定截肢水平量化了经肱骨加载：（1） 体动力钩，（2） 肌电钩，（3） 肌电手，和（4） 先进假肢。构建了计算模型来复制每种假肢类型的重量分布，然后将其应用于在高级日常生活活动（AADLs）期间收集的运动捕捉数据。对于不包括手持重量的活动，体动力假肢的弯曲力矩为 13-33%（每个活动在截肢水平上的平均值范围），完整手臂的力矩（参考 100%）；扭转力矩为 12-15%，轴向拔出力为 30-40%完整案例（p≤0.001）。肌电钩和手的弯曲力矩为 60-99%，扭转力矩为 44-97%，轴向拔出力为 62-101%完整案例。先进假肢的弯曲力矩为 177-201%，扭转力矩为 164-326%，轴向拔出力为 133-185%完整案例（p≤0.001）。在 briefcase carry 和 jug lift 活动中添加手持重量会降低假肢模型本身的整体影响，其中体动力力和力矩与完整模型更为接近，而更复杂的假肢会进一步增加超过完整手臂水平的力和力矩。这些结果根据假肢设备的复杂性显示了加载幅度的排序，并强调了在规划术后经皮 OI 康复和训练时考虑患者所需的终端设备的重要性。
