Quantitative Measurement of Rotational Knee Stability

Abstract

Context: Objectively evaluating knee stability in multiple planes in individuals with anterior cruciate ligament injury may provide more comprehensive information than evaluating subjectively or in only a single plane. This could support both research and clinical decision making. However, for the clinical value of such an instrument to be evaluated, reliability and validity of the instrument must first be established. Despite multiple available instruments that measure rotational knee stability, it is not clear which of these instruments has adequate reliability and validity. Objective: We performed a systematic review to identify instruments for measuring rotational knee stability and to synthesize the available literature in which validity and reliability were evaluated. Evidence Acquisition: We searched 4 databases for publications reporting reliability or validity of an instrument designed to assess rotational knee stability. A narrative synthesis was used to present the results. Evidence Synthesis: We identified 42 studies evaluating 25 different instruments designed to measure movement while applying a standardized torque or while a tester performed a manual test (eg, pivot shift). There was high heterogeneity in parameters reported and criterion methods used. Intrarater and interrater reliability intraclass correlation coefficients were consistently adequate (>.75) except for when lower torques (ie, 6 N·m or less) were applied or acceleration or jerk was measured instead of laxity. Four out of 19 (21.1%) studies evaluating validity reported very good correlations (r > .8) with a criterion measure. Conclusions: We found no highquality evidence that provided sufficient evidence of both reliability and validity in any device. To evaluate the clinical benefit of objectively evaluating stability in multiple planes, further work is needed to develop, refine, and evaluate this class of devices.