PDF(Pubmed)
Abstract：
BACKGROUND: Falls due to stumbling are prevalent for transfemoral prosthesis users and may lead to increased injury risk. This preliminary case series analyzes the transfemoral prosthesis user stumble recovery response to highlight key deficits in current commercially-available prostheses and proposes potential interventions to improve recovery outcomes.
METHODS: Six transfemoral prosthesis users were perturbed on their prosthetic limb at least three times while walking on a treadmill using obstacle perturbations in early, mid and late swing. Kinematic data were collected to characterize the response, while fall rate and key kinematic recovery metrics were used to assess the quality of recovery and highlight functional deficits in current commercially-available prostheses.
RESULTS: Across all participants, 13 (54%) of the 24 trials resulted in a fall (defined as > 50% body-weight support) with all but one participant (83%) falling at least once and two participants (33%) falling every time. In contrast, in a previous study of seven young, unimpaired, non-prosthesis users using the same experimental apparatus, no falls occurred across 190 trials. For the transfemoral prosthesis users, early swing had the highest rate of falling at 64%, followed by mid-swing at 57%, and then late swing at 33%. The trend in falls was mirrored by the kinematic recovery metrics (peak trunk angle, peak trunk angular velocity, forward reach of the perturbed limb, and knee angle at ground contact). In early swing all four metrics were deficient compared to non-prosthesis user controls. In mid swing, all but trunk angular velocity were deficient. In late swing only forward reach was deficient.
CONCLUSIONS: Based on the stumble recovery responses, four potential deficiencies were identified in the response of the knee prostheses: (1) insufficient resistance to stance knee flexion upon ground contact; (2) insufficient swing extension after a perturbation; (3) difficulty initiating swing flexion following a perturbation; and (4) excessive impedance against swing flexion in early swing preventing the potential utilization of the elevating strategy. Each of these issues can potentially be addressed by mechanical or mechatronic changes to prosthetic design to improve quality of recovery and reduce the likelihood a fall.
METHODS: Six transfemoral prosthesis users were perturbed on their prosthetic limb at least three times while walking on a treadmill using obstacle perturbations in early, mid and late swing. Kinematic data were collected to characterize the response, while fall rate and key kinematic recovery metrics were used to assess the quality of recovery and highlight functional deficits in current commercially-available prostheses.
RESULTS: Across all participants, 13 (54%) of the 24 trials resulted in a fall (defined as > 50% body-weight support) with all but one participant (83%) falling at least once and two participants (33%) falling every time. In contrast, in a previous study of seven young, unimpaired, non-prosthesis users using the same experimental apparatus, no falls occurred across 190 trials. For the transfemoral prosthesis users, early swing had the highest rate of falling at 64%, followed by mid-swing at 57%, and then late swing at 33%. The trend in falls was mirrored by the kinematic recovery metrics (peak trunk angle, peak trunk angular velocity, forward reach of the perturbed limb, and knee angle at ground contact). In early swing all four metrics were deficient compared to non-prosthesis user controls. In mid swing, all but trunk angular velocity were deficient. In late swing only forward reach was deficient.
CONCLUSIONS: Based on the stumble recovery responses, four potential deficiencies were identified in the response of the knee prostheses: (1) insufficient resistance to stance knee flexion upon ground contact; (2) insufficient swing extension after a perturbation; (3) difficulty initiating swing flexion following a perturbation; and (4) excessive impedance against swing flexion in early swing preventing the potential utilization of the elevating strategy. Each of these issues can potentially be addressed by mechanical or mechatronic changes to prosthetic design to improve quality of recovery and reduce the likelihood a fall.
摘要：
背景：经股假体使用者由于绊脚石引起的跌倒很普遍，并且可能导致受伤风险增加。本初步案例系列分析了经股假体使用者的绊脚石恢复反应，以突出当前市售假体的关键缺陷，并提出了潜在的干预措施以改善恢复结果。
方法：六名经股骨假体使用者在跑步机上行走时，在早期使用障碍物扰动时，假肢受到了至少三次扰动，中晚摇摆。收集运动学数据来表征响应，而跌倒率和关键运动学恢复指标用于评估恢复质量，并突出显示当前市售假体的功能缺陷。
结果：在所有参与者中，24项试验中有13项（54％）导致跌倒（定义为>50％的体重支持），除一名参与者（83％）外，所有参与者至少跌倒一次，而两名参与者（33％）每次跌倒。相比之下,在先前对七个年轻人的研究中，未受损,非假体使用者使用相同的实验装置，在190项试验中没有发生跌倒.对于经股假体使用者，早期摆动的下降率最高，为64%，其次是57%的中期摆动，然后后期摆动33%。下降趋势由运动学恢复指标反映(峰值躯干角，躯干角速度峰值,被扰动的肢体向前延伸，和膝盖角度在地面接触)。在早期摆动中，与非假体用户对照相比，所有四个指标都不足。在中间摆动，除躯干角速度外，其他都不足。在后期挥杆中，只有前进能力不足。
结论：根据失足恢复反应，在膝关节假体的反应中发现了四个潜在的缺陷：（1）地面接触时对站立膝关节屈曲的抵抗力不足；（2）扰动后挥杆伸展不足；（3）扰动后难以开始挥杆屈曲；（4）早期挥杆时对挥杆屈曲的过度阻抗阻止了抬高策略的潜在利用。这些问题中的每一个都可以通过对假体设计的机械或机电变革来解决，以提高恢复质量并减少跌倒的可能性。
方法：六名经股骨假体使用者在跑步机上行走时，在早期使用障碍物扰动时，假肢受到了至少三次扰动，中晚摇摆。收集运动学数据来表征响应，而跌倒率和关键运动学恢复指标用于评估恢复质量，并突出显示当前市售假体的功能缺陷。
结果：在所有参与者中，24项试验中有13项（54％）导致跌倒（定义为>50％的体重支持），除一名参与者（83％）外，所有参与者至少跌倒一次，而两名参与者（33％）每次跌倒。相比之下,在先前对七个年轻人的研究中，未受损,非假体使用者使用相同的实验装置，在190项试验中没有发生跌倒.对于经股假体使用者，早期摆动的下降率最高，为64%，其次是57%的中期摆动，然后后期摆动33%。下降趋势由运动学恢复指标反映(峰值躯干角，躯干角速度峰值,被扰动的肢体向前延伸，和膝盖角度在地面接触)。在早期摆动中，与非假体用户对照相比，所有四个指标都不足。在中间摆动，除躯干角速度外，其他都不足。在后期挥杆中，只有前进能力不足。
结论：根据失足恢复反应，在膝关节假体的反应中发现了四个潜在的缺陷：（1）地面接触时对站立膝关节屈曲的抵抗力不足；（2）扰动后挥杆伸展不足；（3）扰动后难以开始挥杆屈曲；（4）早期挥杆时对挥杆屈曲的过度阻抗阻止了抬高策略的潜在利用。这些问题中的每一个都可以通过对假体设计的机械或机电变革来解决，以提高恢复质量并减少跌倒的可能性。
