No abstract

There is a considerable amount of young adults who become amputees due to war and violence. For this population, a successful adaptation to their prosthesis depends on the socket fit, which in turn is caused by the volume change of the residual limb during the day. The literature reports several investigations on this topic, most of which use subjects walking on a treadmill to simulate their daily activity. However, this studies are focused on transtibial amputees and do not mention the relationship between this physical activity and other variables such as comfort, volume changes and gait. Therefore, the objective of this paper is to determine the effect of physical activity on the volume of the residual limb, the comfort and the symmetry of gait in traumatic transfemoral amputees. Plaster positive molds of the residual limb, the comfort perception and the gait data of five individuals were obtained at the first time of the day and after three sessions of treadmill walking of 15, 30 and 45 minutes. The positive molds of each individual were scanned and then, the volume was calculated. The gait data was acquired using a marker-based motion capture system and processed to obtain spatio-temporal, kinematic and kinetic parameters, including the Gait Deviation Index (GDI). Based on the literature, specific points of the gait data were selected and the symmetry index was obtain for each of them. A short comfort test was used after each session of treadmill walking. Data was analyzed throughout the tests within each subject. Statistical analysis was performed for the volume and the gait variables to check for statistical significance. After physical activity, a tendency towards residual limb volume decrease was found on almost all subjects, although it was not significant. The percentage of volume change obtained on almost all subjects are within the range considered “good socket fit” according to previous authors. Our results suggest that transfemoral amputees may have smaller volume changes than transtibial after treadmill walking. Significant difference was found on the symmetry index of “Swing phase” between the baseline and the 45-minute test. The values of gait symmetry on the gait parameters were consistent with previous findings regarding transfemoral amputees. The difference that arise may be due to the sample difference (cause of amputation, difference in prosthetic elements and use of walking aids). The lowest symmetry was noticed on the ankle kinematics. The comfort did not significantly change with the selected amount of physical activity. In subsequent research, it is recommended to increase the intensity or time of physical activity and/or increase the number of participants. This results can help the understanding of how the socket/residual limb interface behaves which can improve the design and prescription of prosthetic components.

In lower limb amputees, the comfort and fit of the prosthesis determine whether the user wears or not the prosthesis, fact on which a successful rehabilitation depends. The prosthetic fit is highly related with the relative motion between the socket and the residual limb (i.e., displacement). Displacement has been measured in static and dynamic position and between several surfaces such as skin-socket, liner-socket, bone-socket using various instruments. Marker-based optical tracking system is one of the most recent instruments used for measuring displacement between the socket and the residual limb that solves many of the constraints faced by other measurement instruments. Two options have been reported on the literature for using this instrument: transparent test socket with 2D marker and definite socket with cavities and 3D marker, both facing different limitations. The objective of this study is to evaluate these two options using Marker-based optical tracking system in order to give recommendations and contribute to the use of this method on future research. Two sockets were used for the study: a transparent socket and a definite socket with and without cavities. Six trials were performed using both sockets with three types of markers located inside the socket: 2D circular, 3D hemisphere and 3D sphere. VICON motion capture system was used to detect the visibility of the markers at knee flexion angles (0° to 30°). The results showed that all markers were visible from 15° to 30° knee flexion in all trials. The 2D marker presented difficulty of detection on knee angles from 0° to 10°, especially on the final socket without cavities. 3D hemisphere marker was seen almost all along the knee angles. 3D-sphere marker was visible in all positions, but the relatively large size of these markers may not be adequate to measure displacement. Using the definite socket with the 2D circular and 3D hemisphere markers could be a good option to measure displacement between the residual limb and socket. Using this socket will be closer to reality than doing it on the transparent one. Additionally, the size of the 3D-hemisphere is relatively small, it may not drastically change the behavior between surfaces and as it is a 3D marker it can be better seen by the cameras. Further tests should be done with patients walking all along the path in order to assess if the markers visibility is the same on static and dynamic trials.

No abstract

For lower limb amputees, the socket fit is affected by the physical activity performed during the day. The majority of the studies in this field include only transtibial amputees and do not examine the effects of this variable. This paper aims to determine the effect of physical activity on the volume of the residual limb (RL), the comfort, and the symmetry of gait in traumatic transfemoral amputees. RL volume and gait data of five individuals were obtained at the first time of the day and after three sessions of treadmill walking. The ratio symmetry index of selected points of gait parameters was calculated. A short comfort test was used after each session. Data were analyzed throughout the tests within each subject, and statistical analysis was performed. After the physical activity, a tendency toward volume decrease was found on almost all subjects, although it was not significant. Transfemoral amputees may have smaller volume variations than transtibial after treadmill walking tasks. Significant difference was found on the symmetry index of “swing phase (SWP).” The values of gait symmetry were consistent with previous findings regarding transfemoral amputees. The lowest symmetry was noticed on the ankle kinematics. The comfort did not significantly change with the selected amount of physical activity. In subsequent research, it is recommended to increase the intensity or time of physical activity and/or increase the number of participants. These results can help the understanding of how the socket/RL interface behaves, which can improve the design and prescription of prosthetic components.