Age and Sex Differences Between Patient and Physician-Derived Outcome Measures in the Foot and Ankle

Background: Traditionally, physicians have identified which outcome factors are important to measure in order to determine the success or failure of treatment without any input from patients. The purpose of the present study was to ascertain the five outcome factors that are most important to the patient and the impact that age and sex have on these factors. These five most important patient-derived outcome factors were then compared with factors within two of the most commonly used outcome instruments for the foot and ankle. Methods: Informant interviews, pre-testing, consistency analysis, and pilot testing led to the construction of a twenty-item survey of outcome factors that patients identified as being important in the treatment of their foot or ankle problem. Subjects selected the top five factors and rank ordered them from 1 to 5 (with 1 representing extreme importance and 5 representing least importance). One thousand computer simulations identified the top five factors, and these were subsequently stratified for sex and age. Wilcoxon rank-sum and Benjamini-Hochberg tests were used to compare the data between groups. Results: The survey was completed by 783 subjects. The five most important factors were limited walking (p < 0.05), activity-related pain (p < 0.05), constant pain (p < 0.05), difficulty with prolonged standing (p = 0.754), and inability to do one's job or housework (p = 0.995). Shoe-related issues and foot and ankle weakness were significantly different between the sexes. Constant pain, inability to play sports, inability to participate in a job or housework, and recurrent foot or ankle skin sores or infections were significantly different between age groups. Between 38% and 50% of the outcome points found on two commonly used foot and ankle instruments included factors not of primary importance to the patient. Conclusions: There are sex and age-related differences regarding outcome factors following the treatment of disorders affecting the foot and ankle. As many as 50% of the factors in currently used foot and ankle outcome instruments are not of primary importance to patients.