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.

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.

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

during each study visit while the investigational device was used (half a day), no home use between visits, up to 3 visits per subject over a period of 2 weeks