E. Hanada et al., Measuring leg-length discrepancy by the "iliac crest palpation and book correction" method: Reliability and validity, ARCH PHYS M, 82(7), 2001, pp. 938-942
Objective: To determine the reliability and validity of a clinical measurem
ent of leg-length discrepancy (LLD), by using the iliac crest palpation and
book correction (ICPBC) method.
Design: Intra- and interrater reliability and validity determinations.
Setting: Rehabilitation center.
Participants: Thirty-four healthy subjects, none of whom had an apparent LL
D, as determined by iliac crest palpation.
Interventions: We induced a simulated LLD (7-53 mm) for each subject. To me
asure the LLD, the examiner performed the ICPBC method by palpating the ili
ac crests and correcting identified differences with a book opened to the r
equired number of pages. The thickness of the book correction was measured.
Main Outcome Measures: Reliability LLD measurement (n = 20), by using the I
CPBC method to measure the LLD; construct validity (n = 34), comparing ICPB
C measurement with the extent of the induced LLD; and concurrent validity (
n = 14), the difference in heights of the superior aspect of the femoral he
ads from standing radiographs.
Results: The intraclass correlation coefficients (ICCs) for the intrarater
and interrater reliabilities were .98 and .91, respectively. The ICCs for t
he construct and concurrent validities were .62 and .76, respectively. The
ICPBC method underestimated the induced LLD by a mean difference I standard
deviation of 3.8 +/- 10.3mm (p =.055) and the radiologic measure by 5.1 +/
- 8.6mm (p =.043).
Conclusions: The ICPBC technique for measuring LLD is highly reliable and m
oderately valid. When there is no history of pelvic deformity and the iliac
crests can be readily palpated, we recommend using iliac crest palpation t
o detect LLD, and the book correction to quantify it.