A noncontact sensor for measurement of distal residual-limb position during walking

Abstract

Abstract-A simple noncontact device was implemented for measuring the position of the distal residual limb relative to the prosthetic socket during ambulation. The device was a small and lightweight photoelectric sensor positioned within a frame mounted immediately beneath the socket. Calibration tests showed that the sensor had a displacement range of 60.0 mm. The root-mean-square error for all sources of error considered (different reflective surfaces, peak-to-peak signal noise, drift, nonlinearity, different surface tilt angles, surface curvature, and wetness [simulating sweating]) was <1.95% full-scale output. We used the sensor in a preliminary study on a unilateral, transtibial amputee with diabetes to assess pistoning during ambulation. Results showed an average 41.7 mm proximal displacement during swing phase relative to stance phase. When the subject was walking on a flat surface, pistoning was significantly less (p = 0.000) with a supracondylar strap compared with no supracondylar strap, although the difference was not substantial (0.8 mm). A 5 min rest period caused the limb to displace proximally in the socket approximately 4.8 mm during subsequent walking trials, possibly reflecting limb enlargement and thus a more proximal position in the socket after the rest period. The device can potentially be used in prosthetics research for evaluating clinical features that may affect limb position and pistoning and thus fit.

A new approach for the pistoning measurement in transtibial prosthesis

“…13,17,19,20 Based on our literature review, most of the researchers measured the displacement between the bone and the socket or the soft tissue by using different techniques in static position 2,11,[15][16][17][18]26,27 or during the gait. 14,[19][20][21][22]25 Some tried to mimic the gait by adding certain loads to the prosthesis. 13,20 However, no research was found to measure the displacement between the Iceross Dermo ® liner (thickness: 3mm) and the socket in transtibial or transfemoral prosthesis.…”

“…Utilizing the camera brings the possibility of easy and fast determination of pistoning between the liner and socket and it can be a safe method if X-ray exposure is a concern. 14,25,28 This technique can also be used for measuring the pistoning in transfemoral prostheses. In our study, we could not examine the real pistoning during the gait (dynamic), but we tried to mimic the gait by using different loads.…”

Pistoning assessment in lower limb prosthetic sockets

“…32 Recently, a simple photographic method has been reported 29,36-37 and finally, Gholizadeh et al 38 used Vicon motion analysis system to evaluate pistoning in transtibial amputees. The literature review revealed that the majority of researchers measured the displacement between the bone and the socket, the liner and socket or the soft tissue, by using different techniques in static position 19,29,32,[34][35][36][37][38]53,55 or during dynamic tasks 33,35,54,[60][61] to check pistoning inside the socket. Therefore, the methods available were classified according to whether they utilized static or dynamic pistoning.…”

Transtibial prosthetic suspension: Less pistoning versus easy donning and doffing

“…Thus, both clinicians and researchers should be able to determine the quality of suspension and prevent the negative effects of pistoning (such as gait deviation, skin breakdown, and discomfort) by pistoning measurement [13][14][15][16][17][18][19][20][21][22].…”

“…These include X-ray [12,20,[23][24][25], spiral computerized tomography [26], and photoelectric sensors [22]. These measurement methods are mostly useful for measuring the bone movement inside the socket.…”