A paucity of information exists concerning reliability of the KT-1000 knee arthrometer (MEDmetric Corp., San Diego, CA) when used by different clinicians to assess the same anterior cruciate ligament-deficient patient. The purpose of this study was to determine the reliability and standard error of measurement of four clinicians who routinely report KT-1000 arthrometer values to referring orthopedic surgeons. Two physical therapists and two athletic trainers performed anterior laxity tests using the KT-1000 on 19 subjects. Intraclass correlation coefficients (ICC) and standard error of measurement (SEM) were used to determine reliability. Intratester ICC ranged from .98 to 1.0 and intratester SEM ranged from 0.0 to .28 mm. Intertester ICC and SEM for all four testers were .53 and 1.2 mm, respectively. A 95% confidence interval (M ± 1.96 × SEM) of the intertester variability ranged from −0.18 to 4.52 mm. Therefore, large intertester variation existed in KT-1000 values. Each facility should standardize testing procedures and establish intratester and intertester reliability for all clinicians reporting KT-1000 values.
Kelly R. Holcomb and Cheryl A. Skaggs were students at the Krannert Graduate School of Physical Therapy at the time of this study. Teddy W. Worrell is with the Krannert Graduate School of Physical Therapy, University of Indianapolis, 1400 E. Hanna Ave., Indianapolis, IN 46227. Mark DeCarlo and K. Donald Shelbourne are with the Methodist Sports Medicine Center, Indianapolis, IN 46202.