Background: While "diagrammatic" evaluation of finger joint angles using two folded paper strips as goniometric arms has been proposed and could be an alternative to standard goniometry and a means for self-evaluation, the measurement differences and reliability are unknown.
Questions/purposes: This study assessed the standard and diagrammatic finger goniometry performed by an experienced examiner on patients in terms of (1) intragoniometer and intergoniometer (ie, intrarater) differences and reliability; (2) interrater differences and reliability relative to patients' diagrammatic self-evaluation; and (3) the interrater differences related to patient's hand dominance.
Methods: Sixty-one patients without previous training self-evaluated active extension of all joints of the fifth finger of one hand once using two rectangular strips of paper. A practitioner used a goniometer and a diagram to perform parallel evaluations once in 12 patients and three times in 49 patients. The diagrams were scanned and measured. All evaluations and proportions of differences between the paired measurements of 5° or less were combined for analysis.
Results: Intrarater intraclass correlation coefficients (ICC) based on the second and third practitioner's trials for the proximal interphalangeal joint were greater than 0.99. Reliability was poor when calculations involved the first measurement of the practitioner (ICCs < 0.38). Interrater reliability was poor regardless of the practitioner's trial (ICCs < 0.033). The proportions of the absolute differences of 5° or less between all paired practitioner's measurements were similar. The proportions of the acceptable differences between paired practitioner's and patients' measurements were nonequivalent for the interphalangeal joints. The interrater differences did not depend on patients' handedness.
Conclusions: In experienced hands both techniques produce clinically comparable reliability, but patients' performance in extempore diagrammatic self-evaluation is inadequate. Further studies are necessary to explore whether appropriate training of patients can improve consistency of diagrammatic self-evaluation.