Biomechanical Study of Different Prostheses for Unilateral Transtibial Amputees During Indoor and Outdoor Activities

The goal of this observational study is to evaluate and compare the performance of two prosthetic feet for unilateral transtibial amputees during both indoor and outdoor activities. The main research questions aim to answer are:

1. Can a low-cost prosthetic foot enhance gait mechanics and physical performance in individuals who have undergone traumatic unilateral transtibial amputation, as compared to the traditional K2 - K3 prosthetic feet currently available on the market, during both indoor and outdoor activities?
2. Can the low-cost prosthetic foot meet user satisfaction levels after traumatic unilateral transtibial amputation, when compared to the traditional K2 - K3 prosthetic foot on the market?

Participants will be asked to do

1. Prior to the commencement of the experiment, a professional prosthetist and orthotist will conduct all fitting and alignment procedures for the transtibial amputees. Participants will then be given a two to three-week period to train and acclimate to the individual socket alignment and prosthetic foot.
2. Participants are asked to refrain from consuming caffeine or any stimulants for 24 hours before the tests.
3. Participants will be required to perform the Berg Balance Test.
4. Participants will undergo a series of clinical tests, including: 1) Time to Go Up (measured in seconds), 2) Four Square Step Test (measured in seconds), 3) 10-Meter Walk Test (measured in seconds), 4) Eye Close Standing, 5) Tandem Test, and 6) Functional Reach Test. Each test will be conducted three times. The test items of 4) and 5) will be performed on a force plate (Bertect, Ohio, USA) with dimensions of 400 x 600 mm and a capturing frequency of 1,000 Hz.
5. Participants will be asked to walk on a force plate (AMTI, Advanced Mechanical Technology, Inc., Watertown, USA) at a fixed walking speed of 1.11 ± 0.11m/s, allowing the foot to land naturally on the force plate. Five trials of the gait cycle with a clean foot will be used for analysis.
6. Participants will perform the Counter Movement Jump Test three times with maximum effort on the force plate (Bertect, Ohio, USA), which will be performed without a hand swing.
7. Participants will be asked to perform a 2-minute walking test on flat concrete ground, stairs, and a ramp, respectively.
8. Finally, participants will be asked to complete the Locomotion Capabilities Index questionnaire.

Thirty-nine passive-reflective markers of 14 mm in diameter were placed on the participant (Figure 1) according to the landmarks set of the plug-in full body model. An 8-camera motion capturing system (VICON, Nexus 2.0 Inc., Oxford, UK) and 2 force plates (AMTI, Advanced Mechanical Technology, Inc., Watertown, USA) mounted under the walkway were utilized for gait analysis and recorded 100 frames per second simultaneously. All the systems were calibrated before the experiment.

Eligibility Criteria:
Inclusion Criteria:

* unilateral transtibial amputees,
* with more than 12 months of experience using a prosthesis,
* with a K2 prosthesis or above,
* be able to walk continuously unaided with the prosthetic foot for at least 20 minutes.

Exclusion Criteria:

* with a short or an injured residual limb,
* pregnant,
* any neurological or musculoskeletal diseases,
* have a record of active endocarditis and acute myocarditis/pericarditis,
* experience ongoing unstable angina,
* have uncontrolled cardiac arrhythmia with hemodynamic compromise,
* have had a recent stroke or transient ischemic attack,
* have high blood pressure, etc.