Measurements of knee rotation-reliability of an external device in vivo.

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Knee rotation plays an important part in knee kinematics during weight-bearing activities. An external device for measuring knee rotation (the Rottometer) has previously been evaluated for validity by simultaneous measurements of skeletal movements with Roentgen Stereometric Analysis (RSA). The aim of this study was to investigate the reliability of the device.

The within-day and test-retest reliability as well as intertester reliability of the device in vivo was calculated. Torques of 3, 6 and 9 Nm and the examiner's apprehension of end-feel were used at 90°, 60° and 30° of knee flexion. Intraclass Correlation Coefficient 2,1 (ICC 2,1), 95% confidence interval (CI) of ICC and 95% CI between test trials and examiners were used as statistical tests.

ICC2,1 ranged from 0.50 to 0.94 at all three flexion angles at 6 and 9 Nm as well as end-feel, and from 0.22 to 0.75 at 3 Nm applied torque.

The Rottometer was a reliable measurement instrument concerning knee rotation at the three different flexion angles (90°, 60° and 30°) with 6 and 9 Nm applied torques as well as the examiner's apprehension of end-feel. Three Nm was not a reliable torque. The most reliable measurements were made at 9 Nm applied torque.


  • Per O Almquist
  • Charlotte Ekdahl
  • Per-Erik Isberg
  • Thomas Fridén
Research areas and keywords

Subject classification (UKÄ) – MANDATORY

  • Orthopedics
Original languageEnglish
Article number291
JournalBMC Musculoskeletal Disorders
Publication statusPublished - 2011
Publication categoryResearch

Bibliographic note

The information about affiliations in this record was updated in December 2015. The record was previously connected to the following departments: Division of Physiotherapy (Closed 2012) (013042000)

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