Basic Mobility and Balance Performance of Low Active Transfemoral Prosthesis Users With a Powered Prosthetic Knee

Basic Mobility and Balance Performance of Low Active Transfemoral Prosthesis Users With Mobili Knee (a Powered Microprocessor-controlled Knee Prosthesis)

This was a prospective case series design investigation with 6 prosthesis user subjects. Subjects performed the Timed up and go (TUG) test and the two minute walk test (2MWT) along with some activities of daily living (ADL), on their prescribed knee as well as the investigational device at two separate visits. Performance was compared and statistically analyzed.

Study Overview

• Status: Completed
• Conditions: Amputation; Prosthesis User
• Intervention / Treatment: Device: Investigational device; Device: Prescribed device

Detailed Description

Participants were consented, and all tests were conducted at the Össur Motion lab Grjótháls 1-5, 110 Reykjavik.

There were two scheduled study events. At the initial visit, the first study event, for each subject a researcher qualified to obtain informed consent seated the subject and proceeded as described in chapter 13.7 Informed consent in [2].

Prior to fitting the subject was asked to provide feedback on their prescribed prosthesis, by filling in a questionnaire and perform AMPro, LCI (modified), TUG test, 2MWT and other validation activities (stand to sit, sit to stand, level ground, stair and ramp walking), as applicable. The users were fitted within the standard methods of prosthetic fitting, alignment, introduction, training and walking on various terrain.

After initial fitting subjects carried out validation tasks (stand to sit, sit to stand tasks, level ground walking at different speeds, stair and ramp walking), stroop test (cognitive loading) and FSST on the investigational device, after which they answered an in-house questionnaire to provide feedback.

During the second event, subjects were fitted with the investigational device and asked to perform the TUG, 2MWT and any validation tasks that could not be completed at visit 1 on the investigational device due to time restraints or subject condition.

If for some reason all tasks could not be completed at visit 1 and 2 due to time restraints or subject condition, a third visit was added.

Subjects did not wear the device home between visits.

Statistical Considerations:

Outcomes were inspected for normality. If the data was deemed to have a normal distribution the hypothesis was tested using a two-tailed, paired t-test (Only hypothesis A and B). If data was deemed non-normal that hypothesis was tested using a Wilcoxon signed rank test. Significance level (alpha) will be set at 0.05.

Other endpoints and acceptance criteria were assessed with descriptive statistics only.

• Study Type: Interventional
• Enrollment (Actual): 6

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• 50Kg< body weight < 116Kg
• Cognitive ability to understand all instructions and questionnaires in the study;
• K1-K2 unilateral transfemoral amputees
• Allows for 37mm knee center height to dome of pyramid alignment
• Age ≥ 18 years
• Willing and able to participate in the study and follow the protocol
• Comfortable and stable socket fit (5 or over on the SFCS)

Exclusion Criteria:

• Users with cognitive impairment
• Users aged <18y
• Bilateral amputees
• Users with stump pain affecting their functional mobility
• Users with socket problems
• Users with co-morbidities in the contra-lateral limb, which significantly affect their functional mobility

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: N/A
• Interventional Model: Single Group Assignment
• Masking: None (Open Label)

Number of Arms

1

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Investigational device; All subjects performed outcome measures on their prescribed knee and the investigational device for comparison.	Device: Investigational device; Motorized microprocessor controlled prosthetic knee.; Device: Prescribed device; Passive microprocessor controlled knee and mechanical knee

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Timed Up and Go Test (TUG Test)	Subjects are timed while completing a task of getting up from a chair, walking 3 meters at self-selected walking speed, turning around a cone and returning to sit down in the chair.Time is stopped from leaving the chair until the subject is sitting again. The time is measured in seconds. The faster the subject can complete the task the better. Results correlate with gait speed, balance, functional level, the ability to go out, and can follow change over time. It is assumed that subjects that take longer than 14s to complete the TUG might have a higher risk for falls.	1 week

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
2 Minute Walk Test	Subjects walk at self-selected walking speed for 2 minutes, they shall walk as far as possible	1 week

Collaborators and Investigators

• Sponsor: Össur Iceland ehf

Study record dates

Study Major Dates

• Study Start (Actual): February 5, 2021
• Primary Completion (Actual): February 24, 2021
• Study Completion (Actual): February 24, 2021

Study Registration Dates

• First Submitted: March 11, 2021
• First Submitted That Met QC Criteria: March 11, 2021
• First Posted (Actual): March 16, 2021

Study Record Updates

• Last Update Posted (Actual): January 21, 2026
• Last Update Submitted That Met QC Criteria: January 16, 2026
• Last Verified: October 1, 2025

More Information

Terms related to this study

• Other Study ID Numbers: CII2020111613

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO