Effect of Surgery to Implant Motion and Force Sensors on Vertical Ground Reaction Forces in the Ovine Model
Effect of Surgery to Implant Motion and Force Sensors on Vertical Ground Reaction Forces in the Ovine Model
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DOI：
10.1115/1.4003322
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发表时间：
2011-02-01
影响因子：
1.7
通讯作者：
Butler, David L.
中科院分区：
文献类型：
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作者：
Herfat, Safa T.;Shearn, Jason T.;Butler, David L.
日常生活活动(ADL)在前交叉韧带(ACL)产生复杂的、多方向的力。虽然校准问题排除了在患者身上直接测量的可能性，但可以想象，在克服技术挑战后，可以在动物身上测量前交叉韧带力量。例如，运动和力传感器可以植入动物体内，但研究人员必须确定这些传感器和手术对正常步态的影响程度。我们在这项研究中的目标是确定(1)手术植入膝关节运动传感器和前交叉韧带力传感器是否会显著改变正常的绵羊步态，以及(2)在跑步机上增加步速和步态对手术前后绵羊步态的影响。10只骨骼成熟的雌性绵羊被用来检验4个假设：(1)手术植入传感器会显著降低手术肢体的平均垂直地面反作用力(VGRF)和峰值垂直地面反作用力(VGRF)；(2)手术植入传感器会显著缩短手术肢体的单肢站立时间；(3)提高跑台速度会增加手术前后的垂直地面反作用力；(4)增加跑台等级会增加手术前后的后肢垂直地面反作用力。用带有两个测力板的仪表式跑步机记录两种速度(1.0m/S和1.3m/S)和两种等级(0°和6°)四种不同速度组合的前后肢VGRF。在所有速度和等级的组合中，植入传感器使平均和峰值VGRF分别降低不到10%和20%。在以1.3m/S的速度倾斜行走时，植入传感器显著缩短了手术后肢的单肢站立时间，而在其他活动时对手术后肢的单肢站立时间无明显影响。增加跑台速度会增加术前后肢峰值(但不是平均)VGRF，术后水平行走时仅有未手术后肢VGRF峰值。增加跑台评分(1m/S)可显着增加术前后肢VGRF的平均值和峰值，但术后增加跑台评分对任何反应指标均无显着影响。由于VGRF值超过了术前水平的80%，我们得出结论，术后动物步态接近正常。因此，在进行传感器植入后的实验时，我们可以假设步态正常。最终，我们寻求测量ADL的前交叉韧带作用力，为传统和组织工程前交叉韧带修复和重建提供设计标准和评估基准。[DOI：10.1115/1.4003322]
Activities of daily living (ADLs) generate complex, multidirectional forces in the anterior cruciate ligament (ACL). While calibration problems preclude direct measurement in patients, ACL forces can conceivably be measured in animals after technical challenges are overcome. For example, motion and force sensors can be implanted in the animal but investigators must determine the extent to which these sensors and surgery affect normal gait. Our objectives in this study were to determine (1) if surgically implanting knee motion sensors and an ACL force sensor significantly alter normal ovine gait and (2) how increasing gait speed and grade on a treadmill affect ovine gait before and after surgery. Ten skeletally mature, female sheep were used to test four hypotheses: (1) surgical implantation of sensors would significantly decrease average and peak vertical ground reaction forces (VGRFs) in the operated limb, (2) surgical implantation would significantly decrease single limb stance duration for the operated limb, (3) increasing treadmill speed would increase VGRFs pre- and post operatively, and (4) increasing treadmill grade would increase the hind limb VGRFs pre- and post operatively. An instrumented treadmill with two force plates was used to record fore and hind limb VGRFs during four combinations of two speeds (1.0 m/s and 1.3 m/s) and two grades (0 deg and 6 deg). Sensor implantation decreased average and peak VGRFs less than 10% and 20%, respectively, across all combinations of speed and grade. Sensor implantation significantly decreased the single limb stance duration in the operated hind limb during inclined walking at 1.3 m/s but had no effect on single limb stance duration in the operated limb during other activities. Increasing treadmill speed increased hind limb peak (but not average) VGRFs before surgery and peak VGRF only in the unoperated hind limb during level walking after surgery. Increasing treadmill grade (at 1 m/s) significantly increased hind limb average and peak VGRFs before surgery but increasing treadmill grade post op did not significantly affect any response measure. Since VGRF values exceeded 80% of presurgery levels, we conclude that animal gait post op is near normal. Thus, we can assume normal gait when conducting experiments following sensor implantation. Ultimately, we seek to measure ACL forces for ADLs to provide design criteria and evaluation benchmarks for traditional and tissue engineered ACL repairs and reconstructions. [DOI: 10.1115/1.4003322]