Table 1.

Comparison of methods for assessing leg length discrepancy

Methods	Reliability*	Accuracy*	Magnification	Approximate radiation exposure (mrads) [26]	Approximate charges (U.S. dollars)	Radiographic deformity analysis	Incorporation of height of the foot and pelvis	Typical availability in U.S.	Weight bearing
Clinical
Supine tape measure—“Real” (ASIS to malleolus)	+	+	None	None	Office visit	Not applicable	No	Yes	No
Supine tape measure—“Apparent” (umblicus to malleolus)	+	+	None	None	Office visit	Not applicable	Partial	Yes	No
Standing blocks	+ +	+	None	None	Office visit	Not applicable	Yes	Yes	Yes
Imaging
Teleoreontgenogram	+ + + +	+ + +	~5%	42	$95 [26]	Yes	Yes	Varies	Yes
Orthoroentgenogram	+ + +	+ + +	Minimal	200	$110 [26]	Minimal	No	Varies	No
Scanogram	+ + + +	+ + +	Minimal	200	$110 [26]	No	No	Varies	No
CR	+ + + +	+ + +	Varies with technique (scanogram versus teleoroengenogram)	Varies with technique, less exposure than standard radiography	$137 [38]	Varies with technique (scanogram versus teleoroengenogram)	Varies with technique	Varies	Varies with technique (scanogram versus teleoroengenogram)
MDR	+ + +	+ + + +	None	2	$75 [26]	Yes	Yes	No	Yes
Ultrasound	+ + +	+ +	None	None	Not reported	No	No	No	Yes
CT scan (digital localization image)	+ + + +	+ + + +	Minimal	60	$60 [26]	Minimal	None	Varies	No
MRI	+ + + +	+ + +	Minimal	None	Not reported	Not reported	Not reported	No	No

CR = computed radiography; MDR = microdose digital radiography.

* Please see text for detailed analysis. For simplicity, the increasing number of “+” signs indicate greater degree of reliability/accuracy.