Objective: To determine if 2 methods of calculating upper extremity volume (using arm circumferences) can substitute for water displacement volumetry.
Design: Interrater and test-retest reliability and limits of agreement for volume measures.
Participants: Twenty-five women at risk for lymphedema who had undergone axillary lymph node dissection surgery for breast cancer.
Interventions: Circumference and volume measurements of both upper extremities were taken by 2 physical therapists at an initial visit and by 1 of the therapists 1 week later.
Main outcome measures: Intraclass correlation coefficients (ICCs) were calculated to analyze measurement reliability. Pearson's product-moment correlation coefficient (r) was used to evaluate the relationship between volumetry and calculated truncated cone volumes. Limits of agreement were calculated to determine the level of agreement between the 2 measurement methods.
Results: Interrater and test-retest reliability ICCs for circumferential and volumetric data were .99 and .99, respectively. Pearson's r values were .93 and .97 for the single truncated cone and the summed truncated cone volume calculations, respectively. Limits of agreement (mean +/- 2 standard deviations) were -52 +/- 334mL and -40 +/- 234mL, respectively, between volumetry and the single truncated cone and summed truncated cone calculations.
Conclusions: Calculated and volumetric measurements in this population are both reliable and closely related, but do not agree with each another, and thus should not be used interchangeably.
Copyright 2001 by the American Congress of Rehabilitation Medicine and the American Academy of Physical Medicine and Rehabilitation