Socket Geometry and Clinical Outcomes of Manual vs Digital Sockets for Lower-limb Amputees
NCT Number: NCT06504303
Status: COMPLETED
Study Type: INTERVENTIONAL
Phases: NA
Conditions: Amputation
Interventions: DEVICE: 3D-printed socket
Sponsor: West Park Healthcare Centre
Sex: ALL
Age: ADULT, OLDER_ADULT
Enrollment: 10
Study Design: Allocation: NA|Intervention Model: SINGLE_GROUP|Masking: NONE|Primary Purpose: OTHER
Start Date: 2021-11-10
Completion Date: 2023-11-30
Locations: West Park Healthcare Centre, Toronto, Ontario, M6M 2J5, Canada

Summary:
The most important aspect of a lower-limb prosthesis is the socket as the interface between the human and the mechanical prosthetic system. Proper fit of the socket to the residual limb is a critical factor in determining comfort, suspension, energy expenditure and ultimately the functional efficiency of the remaining prosthesis. Patients may not wear their prosthesis if they find the socket uncomfortable.

Traditional manufacturing of prosthetic sockets is a high-skill process involving several stages. Capturing the shape of the residual limb and modifying the mould is performed with a manual, hands-on approach. This leads to inconsistencies between clinicians, and increases the likelihood of human error. There is opportunity to improve this process with advanced computer-aided design (CAD) and manufacturing (CAM). 3D printing can be leveraged for its ability to effortlessly manufacture one-off, complex and organic shapes, such as prosthetic sockets. However, the digital method removes the tactile feedback that the clinician generally benefits from when manually designing the socket, thus leading to some uncertainty in how they are modifying the socket. Moreover, the difference in the learning curve may cause inconsistencies in modifications made by different clinicians.

While clinicians may be hesitant in their knowledge-transfer from a manual to digital method, sockets designed using CAD still produce successful outcomes. To facilitate wider-spread adoption of 3D printing as a standard tool in the clinic, more research is needed to better understand how the digital design process affects the geometry of the socket, and how this affects clinical outcomes for amputees.

The investigators hypothesize that (1) digitally-designed sockets and manually-designed sockets will have geometric differences, (2) the digitally-designed socket will result in better clinical outcomes compared to manually-designed sockets, and (3) improved clinical outcomes will correlate to geometric differences centred on particular regions of the socket. However, a feasibility study is needed to inform an effective protocol. This feasibility study aims to explore socket geometries and prosthetic outcomes compared between manually-designed and digitally-designed devices for lower-limb amputees. Findings will help in improving the current 3D printing techniques and exploring outcomes for the users.

Primary Outcome Measures: Patient recruitment rates, The number of eligible vs. recruited patients will be tracked throughout the study period., Through study completion, an average of 1 year|Adherence to protocol, Adherence to protocol steps (i.e., casting, CAD, 3D printing, or functional testing protocols) will be tracked throughout the study period and a standardized checklist of procedures will be kept to measure the rate at which procedures are implemented as intended for fidelity assessment., Through study completion, an average of 1 year|Patient retention rates, Patient drop-out rate will be tracked throughout the study period., Through study completion, an average of 1 year
Secondary Outcome Measures: Socket geometric differences, The 3D geometries of the two sockets will be compared by superimposing the two files in CAD software and measuring the dimensional variances over the entire impressions. Global average difference, and local differences at anatomical areas where rectifications are made will be recorded. These include pressure sensitive areas of the patella, tibial tuberosity, distal tibia, fibular head, and medial and lateral femoral condyle; and pressure tolerant areas of the patellar tendon, medial and lateral flare of tibia, lateral flare of fibula, popliteal area, and distal end of stump. Any other major differences that are identified will be measured and their location recorded., Through study completion, an average of 1 year|Socket comfort score change, A numeric scale to capture socket comfort by patients will also be used (0 = not at all comfortable; 10 = very comfortable)., Through study completion, an average of 1 year|Two-minute walk test, Participants will be instructed to walk back and forth, as far as they can in 2 minutes without any further encouragement. One or more practice tests are allowed at least one day before testing. The test administrator will walk behind the subject to minimize the effect of pacing., Performed one day prior to discharge from West Park.|L-test, Participants will be instructed to stand up from the chair, walk straight forward 7 meters, turn 90 degrees, walk 3 meters, turn 180 degrees and return to sit in the chair. A stopwatch will be used to record the time from the word 'go' to when the subject's buttocks first hits the seat surface when they return. The test administrator will use a digital stopwatch to time and a calibrated wheel with a counter to measure the distance walked. One practice run is allowed, followed by 2 trials with a 1-minute rest between trials. The mean times from the 2 trials will be used for data analysis., Through study completion, an average of 1 year
Other Outcome Measures: Demographics, Demographic questions collected from people with LLAs will include: age, sex, cause of amputation, level of education, and work status., Through study completion, an average of 1 year|Physiological Cost Index, Calculated from two-minute walk test heart rates as the difference between resting and active heart rates, divided by the average walking speed based on the distance walked over the 2 minutes. The PCI correlates well with oxygen uptake in amputees, and therefore provides a useful estimate of walking efficiency., Through study completion, an average of 1 year