Effects of socket size on metrics of socket fit in trans-tibial prosthesis users

Abstract

The purpose of this research was to conduct a preliminary effort to identify quantitative metrics to distinguish a good socket from an oversized socket in people with trans-tibial amputation. Results could be used to inform clinical practices related to socket replacement. A cross-over study was conducted on community ambulators (K-level 3 or 4) with good residual limb sensation. Participants were each provided with two sockets, a duplicate of their as-prescribed socket and a modified socket that was enlarged or reduced by 1.8 mm (~6% of the socket volume) based on the fit quality of the as-prescribed socket. The two sockets were termed a larger socket and a smaller socket. Activity was monitored while participants wore each socket for 4wk. Participants’ gait; self-reported satisfaction, quality of fit, and performance; socket comfort; and morning-to-afternoon limb fluid volume changes were assessed. Visual analysis of plots and estimated effect sizes (measure as mean difference divided by standard deviation) showed largest effects for step time asymmetry, step width asymmetry, anterior and anterior-distal morning-to-afternoon fluid volume change, socket comfort scores, and self-reported measures of utility, satisfaction, and residual limb health. These variables may be viable metrics for early detection of deterioration in socket fit, and should be tested in a larger clinical study.

Technology for monitoring everyday prosthesis use: a systematic review

“… Each foot was evaluated over a similar number of steps, but no foot increased activity levels. Sanders (2017) [ 84 ] Effects of Socket Size on Metrics of Socket Fit in Trans-Tibial Prosthesis Users 9 participants (All BK) ActiGraph GT3X (P. Ankle) Steps (2 weeks) Identify metrics of acceptable socket fit in people with BK amputation. Determine if a known change in prosthetic socket size was reflected in objective and subjective measures of fit, comfort, and performance.…”

“…The 27 papers on comparing interventions for lower-limb prosthesis users mostly compared prosthetic components, rather than comparing lifestyle interventions. Studies compared different sockets [ 66 , 79 , 84 ], suspension systems [ 68 , 78 ], knees [ 12 , 64 , 72 – 74 , 87 ], pylons [ 65 ] and feet [ 63 , 70 , 76 , 82 , 83 , 88 , 99 ]. One study compared knees and pylons [ 77 ], and one compared torsion and rigid adapters [ 85 ].…”

A finite element model to assess transtibial prosthetic sockets with elastomeric liners

“…After the first session, participants’ prescribed socket geometries were modified to create the study sockets. The geometry for the study sockets was defined as a surface-normal, uniform offset to the participants’ prescribed prosthesis[54] that accounted for the removal of prosthetic socks, the thinning of the prosthetic liner as it was stretched during the donning process, and any change in thickness between the prescribed and study liners. Two sockets of different uniform offsets were fabricated and tested for fit in the second session.…”

Retracting Locking-Pin Mechanism That Allows Partial Prosthetic Socket Doffing during Sitting

“…Part of the impetus for this research stems from recent findings that doffing a prosthesis temporarily during the day facilitates limb fluid volume recovery and retention in people with limb loss. 8 It is possible that partial doffing will facilitate the same effect. Partial doffing would be more convenient than full doffing for prosthesis users, as it would not require users to remove the entire socket but instead just withdraw the residual limb enough to promote fluid volume recovery.…”