This exploratory interventional study investigates dynamic prosthetic fit in unilateral transtibial prosthesis users by objectively measuring socket-leg interface movements (SLMs) during functional activities. During one single study visit, participants complete standardized laboratory tasks using three different suspension systems (pin-lock, passive vacuum, and active vacuum) applied to a transparent replica of their current prosthetic socket. Motion capture, force measurements, and patient-reported outcomes are used to evaluate how suspension systems influence interface motion, rotation resistance, gait characteristics, and user comfort. The study aims to improve clinical understanding of prosthetic fit and support more informed prosthetic decision-making in routine care.
Age ≥16 years
Unilateral transtibial amputation
Activity level K2-K4
Actively using a prosthesis for ≥12 months
Use of a thigh corset attached to the prosthesis
Requirement of a walker for ambulation
Open wounds, skin ulcers, or blisters on the residual limb
No liner
Single group
Pin-Lock Suspension System
DeviceParticipants perform all tasks using a pin-lock suspension system applied to their test socket.
Passive Vacuum Suspension System
DeviceParticipants perform all tasks using a passive vacuum suspension system applied to their test socket.
Active Vacuum Suspension System
DeviceParticipants perform all tasks using an active vacuum suspension system applied to their test socket.
Socket-Liner Motion [mm]
Socket-liner motion is quantified using a 3D optical motion-capture system to measure the relative movement between the prosthetic socket and liner during functional activities. Motion is recorded in millimeters (mm). Typical motion values are expected to fall within the range of 0-20 mm.
Proximal-distal Socket-Leg Motion [mm]
Proximal-distal Socket-Leg Motion is quantified using a 3D motion-capture system to measure the relative movement between the prosthetic socket and the remaining leg during functional activities. Motion is recorded in millimeters (mm). Typical motion values are expected to fall within the range of 0-30 mm.
Torque Required to Initiate Socket-Liner Rotation [Nm]
This measure quantifies the torque at which transverse rotation begins between the prosthetic socket and liner. Torque is measured in Newton-meters (Nm) using a dynamometer.
Step length [cm]
Step length is quantified using a 3D motion-capture system during functional activities. Step length is recorded in centimeters (cm).
Step length asymmetry index
Step length asymmetry will be assessed using 3D motion analysis instrumentation. Asymmetry is computed on step length (cm) of the prosthetic and intact legs, by dividing the difference between legs by the average of both legs. 0 marks perfect symmetry and greater values higher asymmetry. There is no maximum limit, but most values are expected to be below 1.
Gait velocity [m/s]
Gait velocity is quantified using a 3D motion-capture system during functional activities. Gait velocity is recorded in meters per second (m/s).
Socket-Leg rotation [degrees]
Socket-Leg rotation is quantified using a 3D motion-capture system to measure the relative movement between the prosthetic socket and the remaining leg during functional activities. Motion is recorded in angles (degrees). Typical values are expected to fall within the range of 0-15 degrees.
Step length [% of bodyheight]
Step length is quantified using a 3D motion-capture system during functional ctivities activities. Step length is recorded in centimeters (cm) and presented as percentage of bodyheight.
Knee angle [degrees]
The knee angle is quantified using a 3D motion-capture system during the functional activities and presented in degrees as a function of the gait cycle.
Hip angle [degrees]
The hip angle is quantified using a 3D motion-capture system during the functional activities and presented in degrees as a function of the gait cycle.
Click on the lead sponsor to view all of their trials.
Norwegian University of Science and Technology
Lead sponsor
Trøndelag Ortopediske Verksted (English translation: Trøndelag Orthopedic Workshop)
Collaborator
This trial is not recruiting at the moment. You can still explore other options:
