Comprehensive Evaluation of the Passive Talaris Demonstrator
Condition: Lower Limb Amputation Below Knee (Injury)
Study type: Interventional

Summary: 
      The passive Talaris Demonstrator (TD) is developed in continuation of previous prototypes.
      The main goal of the experiment is to evaluate the effectiveness of TD during daily
      activities.
    

Detailed description: 
      Twenty-eight healthy active participants with an unilateral transtibial amputation will
      conduct 2 experimental trials (EXP1 & EXP2) on the same day in a randomized order, i.e. EXP1
      with the currently used prosthesis and EXP2 with the passive Talaris Demonstrator. Each
      experimental trial will include 6 minutes of treadmill walking at 3 different speeds in
      consecutive blocks of 2 minutes, a slope walking test, a stair climbing test, a L-test and an
      outdoor walking task.

      The six minutes walk test (6MWT) has become one of the most widely used performance-based
      outcome measures of functional mobility and exercise capacity. Recently, the 6MWT has been
      found to correlate with single-limb balance time and symmetry of step length in people with
      amputation. Additionally, the 6MWT distance has been shown to be responsive to functional
      training interventions in people with lower-limb amputation. Six minutes of treadmill walking
      at 3 different speeds will be performed. This test will be performed in consecutive blocks of
      2 minutes. These consecutive blocks will be walking 2 minutes at self-selected (SS) speed, 2
      minutes at 75% of the SS speed and 2 minutes at 125% of the SS speed. These different walking
      speeds elicit different angular positions of the ankle and activation levels of muscles, and
      thus might alter the effectiveness of the novel device.

      The slope walking test assesses the participants' ability to ascend and descend a 6 m long
      ramp of 10% inclination as fast as possible. For safety reasons bilateral handrails are
      warranted. Participants start the test in an upright position in front of the ramp and are
      asked to ascend the ramp, turn around on the platform, descend the ramp and return to the
      starting position.

      The stair climbing test assesses the participants' ability to ascend and descend a staircase
      (84 cm total height, 3-step staircase with an average rise of 28 cm and run of 18 cm).
      Participants start in front of the staircase and are asked to ascend and descend as fast as
      possible. Again, bilateral handrails are required to allow support when needed. The ascending
      phase is initiated with the prosthetic side, while the first step of the descending phase is
      performed with the non-involved leg.

      The L-test, requires higher physical activity of the user. During the L-test, participants
      are asked to rise from a chair, walk 7 meters, turn 90 degrees, walk 3 meters, turn 180
      degrees and then return in the same way to the seated position. A total distance of 20 meter
      is covered.
    

Intervention name(s): Passive Talaris Demonstrator
Intervention type(s): Device
Intervention description(s): The amputee will walk with the passive Talaris Demonstrator, a novel prosthetic foot, designed and built by "Axiles Bionics".
Allocation: Randomized
Intervention model: Crossover Assignment
Masking: None (Open Label)
Primary purpose: Basic Science