GNRB® Knee Arthrometer: Inter- and Intra-observer Reliability and Learning Curve.

Area of Science:

• Orthopedics
• Biomechanics
• Sports Medicine

Background:

• Diagnosing anterior cruciate ligament (ACL) rupture is challenging due to subjective clinical laxity assessments.
• Objective evaluation methods are crucial for consistent clinical research on knee injuries.

Purpose of the Study:

• To evaluate the reproducibility of the GNRB knee arthrometer across different examiners.
• To assess the learning curve for a junior examiner using the GNRB system.

Main Methods:

• Anterior translation measurements were performed on 20 healthy knees using the GNRB arthrometer at 134 N and 200 N push forces.
• Inter- and intra-observer reproducibility were assessed by senior and junior examiners using Cohen's kappa and ICC.
• A third measurement series by the junior examiner evaluated the learning curve.

Main Results:

• The senior examiner showed excellent intra-observer reproducibility (ICC >0.75).
• The junior examiner's initial reproducibility ranged from fair to good (ICC 0.45-0.75), improving to excellent (ICC >0.75) after approximately 20 knees.
• Inter-observer reproducibility between examiners was excellent (ICC >0.75).

Conclusions:

• The GNRB system demonstrates reproducible measurement of anterior knee laxity.
• A learning curve of around 20 knees enables junior examiners to achieve excellent reproducibility with the GNRB arthrometer.