Document Detail

Improved precision in quantifying knee alignment angle.
MedLine Citation:
PMID:  17259895     Owner:  NLM     Status:  MEDLINE    
Knee alignment angle, a measure of mechanical axis, has been reported to correlate with severity and progression of knee osteoarthritis. However, quantification of knee alignment often results in unacceptable reproducibility because of poor definition of landmarks and imprecise measurement techniques. We describe and validate a reproducible, sensitive method. Fourteen patients (28 knees) with symptomatic knee osteoarthritis who had full-limb radiography were evaluated. Knee alignment angle, defined as the angle formed between the mechanical axis of the femur and that of the tibia, was determined using a conventional manual technique and compared with a novel digital method using freely available Image J software to designate landmarks digitally and to determine the angles formed by the femoral and tibial axes. We found agreement between the manual and digital methods. All assessments were performed in duplicate on separate days. Using the manual method, the limits of agreement were +1.65 degrees to -1.55 degrees, yielding a minimal detectable change of approximately 1.6 degrees. However, the digital method provided limits of agreement of +0.43 degrees to -0.37 degrees resulting in a minimally detectable change of 0.4 degrees. We describe a method to reliably determine mechanical axis with precision permitting detection of differences less than 1 degrees.
Berna Goker; Joel A Block
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Publication Detail:
Type:  Clinical Trial; Comparative Study; Journal Article; Research Support, N.I.H., Extramural; Research Support, Non-U.S. Gov't; Validation Studies    
Journal Detail:
Title:  Clinical orthopaedics and related research     Volume:  458     ISSN:  0009-921X     ISO Abbreviation:  Clin. Orthop. Relat. Res.     Publication Date:  2007 May 
Date Detail:
Created Date:  2007-05-02     Completed Date:  2007-06-05     Revised Date:  2007-12-03    
Medline Journal Info:
Nlm Unique ID:  0075674     Medline TA:  Clin Orthop Relat Res     Country:  United States    
Other Details:
Languages:  eng     Pagination:  145-9     Citation Subset:  AIM; IM    
Department of Internal Medicine, Gazi University, Ankara, Turkey.
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MeSH Terms
Image Processing, Computer-Assisted
Joint Deformities, Acquired / physiopathology,  radiography*
Knee Joint / physiopathology,  radiography*
Longitudinal Studies
Middle Aged
Osteoarthritis, Knee / diagnosis*,  physiopathology
Physical Examination
Prospective Studies
Reproducibility of Results
Stress, Mechanical
Grant Support

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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