Error Estimates in Novice and Expert Raters for the KT-1000 Arthrometer

Janet Berry, Kimberly Kramer, Jill M. Binkley, G. Alan Binkley, Skip Hunter, Keith Brown, Paul W. Stratford

Study Design: Single group repeated measures with multiple raters. Objectives: To determine the interrater reliability of KT-1000 measurements of novice and experienced raters and to provide error estimates for these raters. Background: The KT-1000 arthrometer is often used clinically to quantify anterior tibial displacement. Few data have been documented, however, about the relative reliability of KT-1000 measurements obtained by novice compared with experienced users. Methods and Measures: Two novice and two experienced KT-1000 users performed measurements on 29 knees of 25 patients after anterior cruciate ligament (ACL) reconstruction or with a diagnosis of ACL deficiency. Measurements were performed at 131 N. Interrater and intertrial reliability coefficients (interclass correlation coefficient; ICC) and the standard error of measurement were calculated for expert and novice raters. Results: The interrater ICC for novices was 0.65 and the interrater error was ±3.52 mm (90% confidence interval [CI]). The interrater ICC for experts was 0.79 and the interrater error was ±2.94 mm (90% CI). Conclusions: These results suggest that experience in using the KT-1000 is related to the interrater error of measurements and that training is an important consideration when using the KT-1000 arthrometer.

J Orthop Sports Phys Ther. 1999;29(1):49-55.

Key Words: Standard error of measurement, reliability, testing

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