Measurement of limb length inequality. Comparison of clinical methods with orthoradiography in 190 children.

We studied the agreement in measuring limb length inequality with orthoradiograms and clinical methods. In 190 children attending our Limb Length Clinic for the first time, 95% of the measurements with wooden boards was within -1.4 and +1.6 cm of the results of the orthoradiograms. A tape measure had significantly less agreement. The predictive value of a localization of the main limb length inequality above the knee, as found with a tape measure, was 64% and for a localization of the main limb length inequality below the knee 75%. A Wooden Board Reliability Graph is presented, which can be helpful in the decision to perform orthoradiographic measurements of limb length inequality in, e.g., evaluation of impairment.