Development of a Motorized Device for Quantitative Investigation of Articulated AFO Misalignment
the objective of the study is to develop a motorizeddevice to quantitatively investigate the AFO alignment andmechanical properties. The motorized device consists of a servomotor and an inline gear box with a 25:1 gear ratio. Athermoplastic articulated AFO with Tamarack TM dorsiflexionassist flexure joint was investigated in the study. The motor shaftwas used to mimic the anatomical ankle joint. The joint of theAFO was aligned in such a way that the offset could besystematically manipulated (aligned exactly with the center ofmotor shaft, 10mm superior, inferior, anterior or posterior withrespect to the center of motor shaft). The AFO was passivelymoved in the range from 30 o plantar flexion to 20 o dorsiflexion ata prescribed speed of 3 o /s. 11 complete cycles were run lastingabout 400 s. Index of hysteresis was calculated as the ratio of areawithin the loop to the area below the ascending limb andpresented in percentage (%). In addition, passive resistancetorque and quasi-static stiffness were quantified at prescribedpositions. Based on the preliminary results the perfect alignmentwill result in the lowest resistance torque, quasi-static stiffnessand moderate hysteresis index. However, the alignment of 10mm inferior showed the largest hysteresis index indicating anexcessive energy loss during unloading phase and higherresistance torques during the loading phase. It suggested thatalignment excessively below the anatomical joint should beavoided in clinical practice. The alignment of 10 mm superiorshowed comparable quantities to the perfect alignment and couldbe recommended in practice if perfect alignment is hard or notpossible to implement. In summary, we have demonstrated that the device could be a powerful quantitative tool for practitionersand researchers. It is expected that the information obtained will be valuable to clinicians and provide recommendation ondecision-making. In addition, the quantitative results will beuseful in simulation and modeling studies.
Fan Gao William Carlton Susan Kapp
Department of Health Care Sciences School of Health Professions,UT Southwestern Medical Center,Dallas, TX USA
国际会议
成都
英文
1-4
2010-06-18（万方平台首次上网日期，不代表论文的发表时间）