| dc.description.abstract | Introduction: Movement occurring at the socket-limb interface in the prosthesis has a great influence on the lower limb prosthetic user activity and comfort of the prosthesis. Examples of such movements are rotation and pistoning. Pistoning’ also called vertical displacement is the up and down movement of the residual limb inside the socket and is considered as one of the indicators for suspension system efficiency. There are several suspension systems available, but a systematic objective evaluation of the suspension systems to socket-limb interface movement for different activities is lacking.
The study aimed to investigate socket residuum movement mainly vertical displacement in 3 different suspension systems during walking, fast walking, sudden turning, and jumping. In addition, study also aimed to investigate variable like velocity of activity, time of activity during the activities and satisfaction with the suspension used with regards to comfort and stability.
Method: A unique GoPro™ camera-based measurement technique attached to a transparent socket, with a locking textile liner was used to measure prosthetic socket interface movement at the distal end of socket and residual limb interface. In addition, a 3D motion capture system was also incorporated to determine the performance of tasks. The velocity at which the activity was performed, time and height was determined with the 3D system for which the marker placements were more proximal than the camera-based technique. Displacements were calculated using synchronized values from camera records as well as the 3D motion capture system. In addition, Visual analogue scale (VAS) for comfort and stability was administered at the end of the trials for the subjective grading of comfort and stability with the suspension system used. Several trials were conducted with 3 suspension systems for 4 different activities (Normal walking, Fast walking, Turning, and Jumping). The pin-locking textile liner suspension systems tested were “non-vacuum”, “sleeve-passive suction”, and “sleeve-active vacuum”.
Results: The highest average displacement was found in non-vacuum pin-lock suspension for every activity. An average of 1.9 mm, 2.8mm, 1.5mm and 2.2 mm displacement was seen during normal walking, fast walking, turning towards healthy side and turning towards amputated side respectively. For the vacuum system, the sleeve active vacuum showed lesser vertical displacements and less stability score. Pinlock suspension system was perceived the most comfortable system. Displacements increased in every suspension system tested with the increase in velocity of activity performed.
Conclusion: The pin lock non-vacuum suspension system had the overall highest pistoning movement among the 3 suspension systems, therefore may not be a good choice for demanding activities. Irrespective of the type of suspension system used, the pistoning also is seen to increase with the increase in the velocity at which the activity is performed. In terms of comfort, pain, and stability, the pin lock non-vacuum suspension system is observed to be the superior one. | |
