Advanced Prosthetic Devices for Lower Limb Amputees

Overview

Lower limb amputation is an emerging global health concern. Currently, there are over 1.6 million amputees in the U.S. and around 6000 new amputations are recorded per annum in the UK. These numbers are expected to double by 2050 due to the increasing aging population and the adverse health issues such as diabetes, representing a significant, growing problem in western society. A lower limb amputation results in the loss of the biological joint structures such as the ankle and knee, along with the associated musculature. In order to overcome these physical losses, many lower limb amputees are provided with a prosthetic limb that enable them to participate in activities of daily living. The design and function of these prosthetic limbs varies widely, with some being very basic, non-articulating, semi-rigid structures while other more advanced components are computer controlled or incorporate robotic function. Lower limb amputees have been shown to fall more often when compared to age matched individuals without lower limb amputation. This has been reported to be partly a result of a less stable walking pattern. Given that the prosthetic limb provided and it's functional capability is a large component of how well a lower limb amputee is able to walk, it is important to understand what the effects of and potential benefits are from using more advanced prosthetic devices, such as micro-processor controlled knee joints and articulating ankle joints. Therefore, the aim of the current study is to investigate the effects of combining more advanced prosthetic ankle-foot and knee components on the biomechanics of activities of daily living in individuals with above knee amputation.

Study Background Lower limb amputation is an emerging global health concern. Currently, there are over 1.6 million amputees in the U.S. and around 6000 new amputations are recorded per annum in the UK. These numbers are expected to double by 2050 due to the increasing aging population and the adverse health issues such as diabetes, representing a significant, growing problem in western society. A lower limb amputation results in the loss of the biological joint structures such as the ankle and knee, along with the associated musculature. In order to overcome these physical losses, many lower limb amputees are provided with a prosthetic limb that enable them to participate in activities of daily living. The design and function of these prosthetic limbs varies widely, with some being very basic non-articulating semi-rigid structures while other more advanced components are computer controlled and function robotically. Advanced ankle components have been shown to provide lower limb amputees with a number of benefits including increased walking speed, improved symmetry between legs and increased forward progression. In addition, micro-processor controlled knee components, recently made available through the NHS via NHS England Clinical commissioning, have shown a number of benefits. These benefits are stated as being '…enhanced stability and stumble recovery, which improves fall management and reduces the incidence of falls. This supports the increases in self-reported improved individual mobility and independence. MPKs also improve controlled sitting and standing, walking gait symmetry, stair decent, controlled step over step descent down a slope, reduced energy expenditure, and given different modes for different activities an ability to manage obstacles more easily'. Given that the prosthetic limb provided and their functional capability is a large component of how well a lower limb amputee is able to walk, it is important to understand what the effects of and potential benefits are from using more advanced prosthetic devices, such as micro-processor controlled knee joints. Also, as these components are used in conjunction with ankle-foot devices, it is important to know what the optimal combination may be to gain the most benefits from both prosthetic components. Study Aim The aim of the current study is to investigate the effects of combining more advanced prosthetic ankle-foot and knee components on the biomechanics of activities of daily living in individuals with above knee amputation.