Stride activity level in young and middle-aged adults with hip disorders.

OBJECTIVES: To determine the activity level, represented by total daily strides (TDS), of young and middle-aged adults with hip disorders and asymptomatic controls and to assess the association between TDS and self-report functional measures.

METHODS: Patients (age 15-50) with deep hip or groin pain (n=202) and controls (n=20) wore an accelerometer that recorded TDS. Symptomatic subjects completed self-report questionnaires. Symptomatic subjects were classified into subgroups: femoroacetabular impingement (FAI), developmental dysplasia of the hip (DDH), isolated labral tear (LT) and osteoarthritis (OA) based on intraoperative findings. Between-group comparisons of TDS were performed and correlations between TDS and questionnaires were determined.

RESULTS: Overall, controls recorded greater TDS than symptomatic subjects; however, between-group comparisons showed that FAI and DDH were similar to controls. OA demonstrated fewer TDS than FAI (4327 [2075] vs. 5095 [2354]). In symptomatic subjects, TDS had a low correlation with modified Harris Hip Score (r=0.33) and the University of California Los Angeles Activity Score (ρ=0.30), but no correlation with the Marx Activity Rating Scale.

CONCLUSIONS: Subjects with hip disorders demonstrate reduced TDS compared with controls; however, some subgroups demonstrated TDS similar to controls. In addition, symptomatic subjects demonstrated relatively high TDS while reporting poor function. Accelerometers can be used in clinical populations to provide additional information about activity not represented by traditional functional measures.