Variation in measurements of transtibial stump model volume: a comparison of five methods.
OBJECTIVE
To determine the right moment for fitting the first prosthesis, it is necessary to know when the volume of the stump has stabilized. The aim of this study is to analyze variation in measurements of transtibial stump model volumes using the water immersion method, the Design TT system, the Omega Tracer system, circumferential measurements, and anthropometric measurements.


METHODS
Nine stump models were measured on two occasions, each consisting of two sessions. In each session, two observers measured the model using each of the five methods. The grand mean volume for each method was calculated. Variance components and their two-way interactions were calculated of the measurement conditions. Repeatability coefficients were calculated for each method.


RESULTS
The grand means of the five methods show systematic differences in volume measurements. Error variance was small (6.4%) relative to the total variance. Method and interaction between stump model and method contributed 82.6% to the error variance. Repeatability coefficients of the methods ranged from 45 ml for the Omega Tracer system to 155 ml for the anthropometric measurements.


CONCLUSIONS
Error variation in measurement results can be attributed for 82.6% to measurement method and interaction between stump model and method. The Omega Tracer system had the smallest repeatability coefficient, indicating that it is the most reliable method.
Bolt
A
A
Department of Rehabilitation Medicine, Center for Rehabilitation, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands.
de Boer-Wilzing
V G
VG
Geertzen
J H B
JH
Emmelot
C H
CH
Baars
E C T
EC
Dijkstra
P U
PU
D000672:Amputation Stumps / Q000033:anatomy & histology*; D000886:Anthropometry / Q000295:instrumentation / Q000379:methods*; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008953:Models, Anatomic; D017755:Prosthesis Fitting / Q000379:methods