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Variability of Single-Leg Versus Double-Leg Stance Radiographs in the Varus Knee
By Andrew Chen, MD, MS; Valerie Rich, MA, ATC; Elizabeth Bain, MPH; William I. Sterett, MD
J Knee Surg. 2009; 22:213
ABSTRACT
We evaluated measured radiographic parameter variability between single-leg stance (SLS) and double-leg stance (DLS) radiographs in patients with varus knee malalignment, indicated for high tibial osteotomy. Fifty-three consecutive knees (mean, 49 years; range, 18-79 years) were evaluated for varus thrust. SLS and DLS radiographs were obtained. A single blinded observer measured mechanical axis angles and weight-bearing line (WBL) deviation using a goniometer. Mechanical axis angles averaged 9.1° (DLS) and 11.3° (SLS). SLS radiographs averaged 9% greater WBL medialization than did DLS. Medial opening averaged 16.4 mm (DLS) and 18.8 mm (SLS). DLS and SLS radiographs showed no significant differences in patients without varus thrust. Patients with varus thrust demonstrated differences in mechanical axis angles (DLS, 9.4°; SLS, 12.2°), WBL deviation (12.1% less), medialization (DLS), and medial opening necessary for correction (DLS, 16.6 mm; SLS, 20.3 mm). In varus thrust, SLS radiographs more closely replicate dynamic knee malalignment, possibly providing more accurate measurements of angular deformity.
[J Knee Surg. 2009;22:213-217.]
AUTHORS
Dr Chen is from Littleton Orthopaedics, Littleton, NH; Ms Rich is from University of South Florida-Athletics, Tampa, Fla; and Ms Bain and Dr Sterett are from Steadman-Hawkins Research Foundation, Vail, Colo.
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The corporate sponsors of the Steadman-Hawkins Research Foundation include Smith & Nephew Endoscopy, Arthrex, OrthoRehab, Ossur Americas, VVMC, ArthroCare, and Genzyme; however, these contributions did not directly support this study.
Correspondence: William I. Sterett, MD, Steadman-Hawkins Research Foundation, Attn: Clinical Research, 181 West Meadow Drive, Suite 1000, Vail, CO 81657.
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