title: Measurement of varus-valgus and internal-external rotational knee laxities in vivo--Part I: assessment of measurement reliability and bilateral asymmetry.
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 degrees , 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 degrees for VR-VL and 3-4 degrees 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.
authors: Applied Neuromechanics Research Laboratory, Department of Exercise and Sport Science, University of North Carolina at Greensboro, 237B HHP Building, P.O. Box 26170, Greensboro, North Carolina 27402-6170, USA. sjshultz@uncg.edu
authors: Sandra J
authors: SJ
authors: Shultz
authors: Yohei
authors: Y
authors: Shimokochi
authors: Anh-Dung
authors: AD
authors: Nguyen
authors: Randy J
authors: RJ
authors: Schmitz
authors: Bruce D
authors: BD
authors: Beynnon
authors: David H
authors: DH
authors: Perrin
mesh_terms: D000328:Adult; D001696:Biomechanical Phenomena / Q000295:instrumentation; D005260:Female; D006801:Humans; D007593:Joint Instability / Q000175:diagnosis; D007719:Knee Joint / Q000502:physiology*; D008297:Male; D009068:Movement / Q000502:physiology*; D015203:Reproducibility of Results; D012399:Rotation