Measurement of varus–valgus and internal–external rotational knee laxities in vivo—Part I: assessment of measurement reliability and bilateral asymmetry

UNCG Author/Contributor (non-UNCG co-authors, if there are any, appear on document)
Randy J. Schmitz, Associate Professor (Creator)
Sandra J. Shultz, Professor and Chair (Creator)
The University of North Carolina at Greensboro (UNCG )
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Abstract: We examined the capabilities of the Vermont Knee Laxity Device (VKLD) in measuring varus (VR)–valgus (VL) and internal (INT)–external (EXT) rotational laxities by quantifying measurement consistency and absolute measurement error (N=10). Based on the expected measurement error, we then examined side-to-side differences (N=20). For all measures, the knee was flexed 20°, the thigh securely fixed, and counterweights applied to the thigh and shank to create an initial zero shear and compressive load across the tibiofemoral joint. A 10-Nm torque was applied to the knee for VL and VR during non-weight-bearing, and a 5-Nm torque was applied for INT and EXT during non-weight-bearing and weight-bearing conditions. Position sensors measured angular displacements (deg). Except for INT during weight bearing, measurement consistency was good to excellent (range, 0.68–0.96), with absolute measurement errors generally less than 2° for VR–VL and 3–4° for INT–EXT. Although side-to-side differences were observed, they did not exceed absolute measurement errors. The VKLD yields reliable measures of VR–VL and INT–EXT laxities, with sufficient measurement precision to yield clinically relevant differences.

Additional Information

Journal of Orthopaedic Research. 2007; 25(8):981-988.
Language: English
Date: 2007
bilateral asymmetry, measurement agreement, frontal plane knee laxity, transverse plane knee laxity

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