Predicting ambulatory function following lower extremity trauma using the functional capacity index.

This study evaluated the accuracy of experts' predictions of ambulatory function following lower extremity trauma using the Functional capacity index (FCI). Data from three orthopedic trauma studies designed to determine long-term function following specific types of lower extremity injuries were used to examine the extent of agreement between the reported and predicted ambulatory function of 921 subjects. Functional limitations reported by the cohort using a generalized health status measure and more detailed questions on lower extremity function were compared with those predicted by experts based on the injuries sustained. The overall agreement between predicted and self-reported FCI function for ambulation was relatively low (31%). In the majority of cases (80%), the disagreement differed by one functional level. Subjects were more likely to report worse function than predicted by the experts. Multivariate modeling identified different injuries, combinations of injuries, and patient characteristics that significantly influenced agreement. For example, subjects who sustained both a tibia and a femur fracture were three times more likely than subjects who did not sustain either fracture type to report poorer ambulatory function than predicted. Many challenges are faced in predicting long-term function following trauma. More empirical data are needed to inform the process. These data suggest that until the FCI can more accurately predict long-term ambulatory function following different lower extremity injuries, it should not be used for this purpose.