Inter- and Intra-Observer Reproducibility and Validity of an Indirect Volume Measurement in Transtibial Amputees

Abstract

The objective of the study was to assess the measurement properties of an indirect volumetric measurement using segmental circumferential measurements fitted into a formula of a truncated cone (Sitzia's method) in long-term transtibial amputees. Twenty-eight participants with a transtibial amputation 41 year participated in the study. Two observers measured stump volume twice, two weeks apart, using both Sitzia's method and the water displacement volumetric method (criterion standard test). The mean differences and upper and lower limits of agreement between the water displacement volumetric method and Sitzia's method, between the first and second assessment, and between both assessors were calculated. Intra-class correlation coefficients (ICCs) were derived from random-effects two-way analysis of variance. Inter-observer agreements of both methods were high and ranged from 86-96%. Intra-observer agreement ranged between 57% and 71%. In both methods the inter-and intra-observer differences were not significant. ICCs ranged from 0.88-0.99 and were better for inter-observer compared to intra-observer reproducibility. Lower stump volumes were observed in Sitzia's method compared to water displacement volumetric method, with high ICC's (0.92-0.95) between both methods. Although Sitzia's method systematically underestimates stump volume, it is a reliable and feasible alternative to the criterion standard test. To determine its validity to detect (longitudinal) differences in stump volume, follow-up research is needed in participants with recent amputations.

Reliability and validity of the iSense optical scanner for measuring volume of transtibial residual limb models

“…These methods include the water displacement method, the circumferential measurement method and optical or laser scanners. 2 –9 The water displacement and circumferential measurement methods are relatively cheap and simple to use. Studies examining the water displacement and circumferential measurement methods have found them to be reliable (intraclass correlation coefficient (ICC) = 0.93–0.98) and valid (ICC = 0.92–0.95).…”

“…Studies examining the water displacement and circumferential measurement methods have found them to be reliable (intraclass correlation coefficient (ICC) = 0.93–0.98) and valid (ICC = 0.92–0.95). 8 However, these measurement methods have their disadvantages. The water displacement method cannot be used to measure residual limb volume in certain patients, for example, patients whose wounds have not healed, or patients who are unable to stand on one leg.…”

Measurement properties and usability of non-contact scanners for measuring transtibial residual limb volume

“…residual limb volume remains challenging, due to patient and measurement related factors such as subject movement, post doffing volume change, distortion of limb shape, accuracy, and resolution of the system. 3,4 Several methods for residual limb volume measurement have been used, such as the water immersion method, [5][6][7][8] mathematical methods, [7][8][9] ultrasound measurement, 10 (spiral) computed tomography scans, 11,12 magnetic resonance imaging, 13 bio impedance measurements, 14 and computer-aided design/computer-aided manufacturing (CAD/CAM) systems, including non-contact scanners. 7,8,15,16 Non-contact scanners have been developed to collect data about residual limb shape for prosthetic socket design.…”

Body Structures and Physical Complaints in Upper Limb Reduction Deficiency: A 24-Year Follow-Up Study

“…Water plethysmography has a high inter- and intra-rater reliability and is seen as the gold standard for volume measurement of a limb [17]–[19]. The displaced water was measured with 1 ml precision.…”