The American academy of orthopaedic surgeons outcomes instruments: normative values from the general population

The collection of population-based normative data is a necessary step in the process of standardization of eleven American Academy of Orthopaedic Surgeons (AAOS) musculoskeletal outcomes measures. These data serve as comparative normative scores with which to assess the effectiveness of treatment regimens in clinical practice settings and to study the clinical outcomes of treatment in musculoskeletal research.

With use of a panel mail methodology, self-reported data on the eleven AAOS musculoskeletal outcomes measures were collected from the general population of the United States.

The overall response rate of 67.4% for the various surveys met study expectations. For the eleven measures, the range of the confidence intervals for the surveys was +/-1.6% to +/-2.3%, exceeding the +/-3% set a priori. With use of the Multitrait/Multi-Item Analysis Program, all of the scales within each of eleven measures exhibited high internal reliability as well as discriminant and convergent validity. Items within each of the scales contributed roughly equal proportions of information to the total scale scores.

All eleven instruments met study expectations for providing reliable and valid normative data for use in clinical and research settings.