The effect of limb length discrepancy on health-related quality of life: is the '2 cm rule' appropriate?

The primary goal of surgical equalization of lower extremity limb length discrepancy is to enhance the quality of life of patients by improving their function, gait, appearance, and pain secondary to compensation for the limb length discrepancy. While many surgeons use a cutoff point of 2 cm as an indication for intervention, little attention has been given to the effect of limb length discrepancy on quality of life. Therefore, the purpose of this study was to determine the relationship between limb length discrepancy and health-related quality of life and to assess whether the commonly accepted 2 cm cutoff serves to predict patients with and without quality of life perturbations. The Child Health Questionnaire was used to collect information from the parents of 76 children diagnosed with limb length discrepancy, and these data were compared with data from scanograms. Differences in quality of life became more apparent with increasing limb length discrepancy, especially among psychosocial health domains. As expected, patients with a limb length discrepancy of 2 cm or below generally fared better than patients with larger discrepancies, but no discrete cutoff could be identified within this group.