Advanced Prosthetic Devices for Lower Limb Amputees

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.

Inclusion criteria

• Transfemoral amputation: Individuals who have had unilateral transfemoral amputation.
• Demographics: Adult, community-dwelling individuals above the age of 18 in order to provide written informed consent for themselves.
• Mental Capacity: Ability to comprehend and understand communication and instruction in English in order to consent and safely participate in study as assessed verbally.
• Mobility level: Prospective participants must be able to negotiate obstacles such as ramps and stairs thus displaying a level of mobility commensurate with a medicare K3 functional classification level.
• Endurance Capacity: Able to walk continuously for periods of up to two minutes at a time in order to complete the clinical walking tests.
• Vision: Good (corrected) vision to safely walk in well-lit areas.
• Cardiovascular Health: No self-reported unresolved cardiovascular complaints to avoid any cardiovascular complications when performing activities of daily living.
• Able to travel: Data collection will take place at Nottingham Trent University, Clifton Campus.

For the otherwise healthy control (CTRL) group, the same criteria apply, with the exception of those pertaining specifically to amputation status.

Exclusion criteria

• Pain: Experience undue musculo-skeletal pain during walking that causes individual to stop and not be able to continue when walking at a self-selected speed.
• Disease/Illness: Unable and/or unsafe to carry out tasks due to disease/illness such as rheumatoid arthritis.
• Injury: Current neuromuscular, musculoskeletal injury.
• Falls: Falls regularly (>1 a month) as determined using the PROFANE fall definition. Excludes recreational, sporting or occupational falls outside of this definition.
• Residuum health: Presence of significant blisters, wounds and rash which prevent prosthesis, sock and liner to be worn comfortably.
• Residuum stability: Observing substantial changes to the physical condition of the lower limb that requires medical attention as judged by the participant, and if after consenting and participating in the study, individuals are referred to mobility services due to a degradation of the physical condition of either lower limb.
• Unable to follow instruction or cognitive deficits: Risk of further injury whilst completing tasks incorrectly.
• Not able to understand written and verbal English: All communication will be in English as the University does not provide translation services.
• For the otherwise healthy control (CTRL) group, the same criteria apply, with the exception of those pertaining specifically to amputation status.