RT Journal Article
SR Electronic
T1 Comparison of Lifts Versus Tape Measure in Determining Leg Length Discrepancy
JF The Journal of Rheumatology
JO J Rheumatol
FD The Journal of Rheumatology
SP 1689
OP 1694
DO 10.3899/jrheum.131089
VO 41
IS 8
A1 Maziar Badii
A1 A. Nicole Wade
A1 David R. Collins
A1 Savvakis Nicolaou
A1 B. Jacek Kobza
A1 Jacek A. Kopec
YR 2014
UL http://www.jrheum.org/content/41/8/1689.abstract
AB Objective. To evaluate the validity (accuracy) and reliability of 2 commonly used clinical methods, 1 indirect (lifts) and 1 direct (tape measure), for assessment of leg length discrepancy (LLD) in comparison to radiograph. Methods. Twenty subjects suspected of having LLD participated in this study. Two clinical methods, 1 direct using a tape measure and 1 indirect using lifts, were standardized and carried out by 4 examiners. Difference in height of the femoral heads on standing pelvic radiograph was measured and served as the gold standard. Results. The intraclass correlation coefficient assessing interobserver reliability was 0.737 for lifts and 0.477 for tape measure. The remainder of the analysis is based on the average of the measurements by the 4 examiners. Pearson correlation coefficients were 0.93 for the lifts and 0.75 for the tape measure method. Paired sample t tests showed difference in means of 2 mm (p = 0.051) for lifts and −5 mm (p = 0.007) for tape measure compared with radiograph. Sensitivity and specificity were 55% and 89% for lifts and 45% and 56% for tape measure, respectively, using > 5 mm as the definition for LLD. The wrong leg was identified as being shorter in 1 out of 20 subjects using lifts versus 7 out of 20 using tape measure. Conclusion. The indirect standing method of LLD measurement using lifts had superior validity, interobserver reliability, and specificity in comparison with radiograph over the direct supine method using tape measure. Both clinical methods underestimated LLD compared with radiograph.