Influence of prior activity on residual limb volume and shape measured using plaster casting: Results from individuals with transtibial limb loss

Abstract

The purpose of this research was to determine if prior activity affected the shape of a plaster cast taken of a trans-tibial residual limb. Plaster casts were taken twice within a day on 24 participants with trans-tibial limb loss, with 5 s between doffing and casting in one trial (PDI-5s), and 20 min in the other trial (PDI-20m). The ordering of the trials was randomized. The mean radial difference between PDI-20m and PDI-5s was 0.34mm (s.d. 0.21) when PDI-5s was conducted first and −0.02mm (s.d. 02.0) when PDI-20m was conducted first. Ordering of the trials had a statistically significant influence on the mean radial difference between the two shapes (p=0.008). The result shows that prior activity influenced the residual limb cast shape. Practitioners should be mindful of prior activity and doffing history when casting an individual’s limb for socket design and prosthetic fitting.

Selecting Appropriate 3D Scanning Technologies for Prosthetic Socket Design and Transtibial Residual Limb Shape Characterization

“…This study's high resolution shape deviation mapping extends prior casting reliability investigations which considered global metrics including volume, length and cross section area 9,10 to compare casting methods, and analysis of rectifications subsequent to the shape capture itself 4 . The most notable prior application of these shape deviation mapping techniques to casting was conducted by Sanders et al, addressing the specific question of the influence of the time delay between an activity protocol and casting 8 .…”

“…Benchmark measures might be taken from research on manual plaster methods, the traditional and most frequently used approach. The consistency of plaster cast rectification has been investigated in terms of the location and depth of focal rectifications 4 , and the influence of prior activity on the residuum's volume and shape 8 . Others have compared hands-off vs. hands-on casting methods in terms of the cast shape radius in a manikin model 9 , and the cast shape volume and length 10 .…”

“…The consistency of plaster cast rectification has been investigated in terms of the location and depth of focal rectifications 4 and the influence of prior activity on the residual limb's volume and shape. 12 Others have compared hands-off versus hands-on casting methods in terms of the cast shape radius in a manikin model 13 and the cast shape volume and length. 14 However, more understanding is needed regarding the benchmark metrics relating to the reliability of both clinically relevant shape metrics and volumetric parameters, against which to compare 3D scanning technologies.…”