Abstract
Introduction
Circumferential measurements (CMs) are used by hand therapists to monitor digital oedema. There are a range of tape measures available commercially to measure digital circumference, but none of them have any data to support their reliability or validity.
Method
Observational measurement studies using a repeated measures design were undertaken to assess if a weighted tape measure, used with a protocol, could provide accurate and reliable CMs of swollen digits.
In study 1, validity and responsiveness were determined by two raters measuring 16 steel bars of known circumferences and comparing the known measurements to those taken with the weighted tape. In study 2, intra- and inter-rater reliability was assessed by three raters measuring 12 prosthetic digits. In study 3, 27 swollen digits were measured by three raters to assess intra- and inter-rater reliability of the raters using the weighted tape in a clinical setting. The analysis of validity was based on the Bland–Altman plots. Reliability was based on the intraclass correlation coefficient (ICC).
Results
There was near-perfect agreement between the measurements taken by two assessors at the start and end of the trial and the actual circumference of the steel bars (all mean differences <1 mm). A minimum change in circumference of 2 mm could be detected with the same rater and a change of 3 mm could be detected with a different rater. On swollen digits the ICC values were significantly greater than 0.9 for both inter- and intrarater reliability. The lowest values for inter-rater reliability were ICC 0.983 (0.965–0.992) and for intrarater reliability were ICC 0.978 (0.954–0.990).
Discussion
The weighted tape measure has been shown to be valid and reliable in this study when used with a protocol for measuring swollen digits. It was easy to use and may become a clinically useful tool.
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