In the first clinical study, a set of combinations of the three hardware (HW) modules of the CLs++ ortho-prosthesis, namely the Active Trans-femoral Prosthesis (ATP), the Active Pelvis Orthosis (APO) and the Active Knee Orthosis (AKO) will be tested, along with the Wearable Sensory Apparatus (WSA), the Bidirectional Interface (BI) and the control software (SW).
The recruitment of potential participants will be carried out by a multidisciplinary team (physicians, physiotherapists and psychologists) and will be aimed at ascertaining the inclusion and exclusion criteria as reported in the "Eligibility" section. If the potential participant fulfills the requirements to be enrolled, the responsible for the study will provide him/her with the information sheet and will answer all possible questions. Once the participant agrees to participate in the study, he/she will sign the informed consent form. An appointment will also be arranged with the orthopedic workshop to make a spare socket to be used with the ATP.
The protocol of the CLs++ first clinical study will be constituted by two main phases.
The first phase is expected to last one week and it has the goal to explore the functionality of the CLs++ HW and SW modules in structured or semi-structured clinical settings by means of a preliminary initial set of activities. In particular, the enrolled participants will be testing 4 different combinations of CLs++ modules:
a) APO + WSA + BI; b) ATP + WSA; c) APO + ATP + WSA; d) APO + AKO + WSA.
This set of experiments will allow to collect relevant data at the beginning of the protocol in order to assess the functionality of the CLs++ system for each participant. Furthermore, the appropriate combination of the three HW modules of the CLs++ ortho-prosthesis will be selected among one of the above combinations. The selection will be performed with participants walking overground and on a treadmill at their self-selected speed, to optimally match the specific user needs based on their residual movement ability and required movement assistance. Specifically, the appropriate combination of the CLs++ modules will be selected based on both the clinical evaluation (e.g. walking asymmetry, stump length, flexion-extension hip strength, strength of the contra-lateral limb) and the subjective feedback, in terms of comfort and perceived functionality, from the participant.
Assessments will be performed at the beginning and at the end of the 1-month familiarization/training period, with participants wearing both their customized combination of the CLs++ modules and their own prosthesis only. The functional assessments will be performed using a treadmill to be able to control all variables: however, we will also perform some test during over-ground walking. In addition to the assessments reported in the section "Outcome Measures", the study foresees the administration of the System Usability Scale (SUS) to assess the usability of the CLs++ system. The study also foresees the development of ad-hoc tools for investigating the economic dimension.
The second phase of the study will consist of an hospital-based familiarization/training walking on the treadmill and overground with the selected combination of CLs++ modules, 1 hour 3 times a week for 1 month. Worthily, training sessions will be mainly focused on the familiarization to the use of the customized combination of CLs++ modules rather than on aerobic training. Thus, the work load, as expressed by the walking speed overground or on the treadmill, will not be critical. Further, participants will be asked to walk at their self-selected speed and will be allowed to stop walking whenever they feel tired and to start again walking once they have recovered.
After 2 weeks of familiarization/training, the set of assessments can be repeated in order to assess whether the experience gained in the training period has effects on a different set of CLs++ modules. Notably, the initial set of modules identified for each patient will be kept unchanged for the whole duration of the familiarization/training, and the intermediate session will be used as evaluation means.
From a statistical point of view, as reported in the "Study Design" section, a sample size of 16 subjects will be able to detect a 15% change in walking-related physical effort, in terms of oxygen uptake during the six-minute walk test, in a single group of trans-femoral amputees with a statistical power \> 0.9 at the two-sided 0.05 alpha-level. Descriptive statistics will be used to present results, while appropriate inferential statistics will be used to ascertain possible significant differences. Data will be also analysed following a case-series approach: data of each patient will be analysed separately in order to highlight the occurrence of differences between pre- and post- assessment sessions, or any learning effect over the familiarization/training time.
