C-Leg 3 and C-Leg 4 Study in Transfemoral Amputees

A Randomized, Blinded, Cross-over Trial to Evaluate the Safety, Functional Mobility and Satisfaction of the Microprocessor Controlled Prosthetic Knee Component C-Leg 4 in Transfemoral Amputees

The aim of this post-market study is to confirm that the microprocessor controlled prosthetic knee components (C-Leg 3 and C-Leg 4) in comparison to mechanical knee joints can bring additional benefit to the users primarily on level walking and secondarily in safety, stair and hill mobility, activities of daily living, satisfaction and preference.

During the last two decades many microprocessor controlled knee joints (MPK) appeared on the market.The newly developed C-Leg 4 aims to provide improved standing function while in the same time offering technology of knee´s previous version (C-Leg 3). Since added functional benefit of a knee joint cannot be anticipated just due to the fact that the knee is controlled by the microprocessor, the aim of this post-market study is to evaluate the safety, functional mobility and satisfaction of the microprocessor controlled prosthetic knee components C-Leg 3 and C-Leg 4 in comparison to mechanical knee joints. Additional goal is to improve the methodological quality of research conducted in the field.

Inclusion Criteria:

• Person is >18 years old.
• Person is a unilateral transfemoral or knee-disarticulation amputee with stabilized residual limb.
• Person is a K2, K3 or K4 ambulator based on Medicare Functional Classification Level (MFCL).
• Person is currently fitted with a prosthesis using a non-microprocessor controlled prosthetic knee for at least 6 months.
• Person was never fitted with microprocessor controlled prosthetic knee joint.
• Person is willing and able to independently provide informed consent.
• Person is willing to comply with study procedures.
• Person wears prosthesis daily and ≥ 8 hours/day.
• Person is walking on average 1km/day.
• Person is walking not slower than 3km/h (~0.8m/s) (based on 10m walk test conducted during recruiting).
• Person is walking on level ground in a step over step manner.

Exclusion Criteria:

• Person is under 18 years of age.
• Person who weighs more than 136kg.
• Person who weighs less than 50kg.
• Person who is pregnant.
• Person has a history of chronic skin breakdown on the residual limb.
• Person has conditions that would prevent participation and pose increased risk (e.g. unstable cardiovascular conditions that preclude physical activity such as walking).
• Person falls ≥ once a week due to the reasons that could not be corrected by the new prosthesis (for ex. problems with vestibular system).
• Person is using under arm axillary crutches or walker.
• Person in an emergency, life threatening situation.
• Person is unwilling/unable to follow instructions.
• Person who is not available to follow the entire study protocol.
• Person who is participating in another study or intends to participate in another study during this study duration.
• Person who cannot personally provide their consent.
• Person who is not wearing prosthesis 8hours/day on average.
• Person who has a score on 10m walk test less than 3km/h (~0.8m/s) (based on 10m walk test conducted during recruiting).
• Person who walks on average less than 1km per day.
• Person who is not able to walk on level ground in a step over step manner.