Leg length inequality measured by ultrasound and clinical methods.

Leg length inequality (LLI) was determined by ultrasound and two clinical methods in 100 subjects without previous disorders of the lower extremities. The mean LLI by ultrasound was 4.1 mm (range: 0-16 mm). An LLI of 10 mm or more was found in 4% of the subjects. The mean inter-observer variation by ultrasound was 0.9 mm (range: divided by 5-8 mm), which was significantly less than that obtained by clinical methods. The 95% confidence interval of inter-observer variation (+/- 2 SD) by ultrasound was +/- 5 mm and this interval is assumed to represent the accuracy of the method. Because LLI measurement by ultrasound is more reliable than clinical methods, ultrasound is recommended for routine use in clinical practice.