Variation in Measurements of Transtibial Stump Model Volume

Abstract

Bolt A, de Boer-Wilzing VG, Geertzen JHB, Emmelot CH, Baars ECT, Dijkstra PU: 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. Design: 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. Disclosures: A summary of the results of this research has been presented at the annual conference of the Dutch national member society of the International Society for Prosthetics and Orthotics (ISPO) on October 2, 2009, in Utrecht, The Netherlands. This presentation was for a Dutch audience (in Dutch). A summary of the results of this research will be presented at the international conference of the International Society for Prosthetics and Orthotics (ISPO) in May 2010 in Leipzig, Germany. OIM Orthopedie (Assen, the Netherlands) provided the stump models. Otto Bock Benelux (Son en Breugel, the Netherlands) provided the Design TT System for the duration of the study. Ohio Willow Wood Benelux (Harderwijk, the Netherlands) provided the Omega Tracer System for the duration of the study. There are no financial relationships between the authors and the above-mentioned companies. The authors have not received financial benefits for accomplishing this research project. Financial disclosure statements have been obtained, and no conflicts of interest have been reported by the authors or by any individuals in control of the content of this article.