The Relationship of Self-Reported Pain and Functional Impairment to Gait Mechanics in Overweight and Obese Persons With Knee Osteoarthritis

Objective: To examine the degree to which 2 commonly used measures of pain and disability, the Arthritis Impact Measurement Scales (AIMS) and the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), relate to objective gait measurements. Design: A descriptive study of the influence of self-reported pain and perceived functional impairment on gait mechanics in osteoarthritic adults. Setting: A university clinical research laboratory. Participants: Overweight/obese adults with radiographic knee osteoarthritis (OA) as well as pain and disability associated with the disease (N = 179). Interventions: Not applicable. Main Outcome Measures: The AIMS and WOMAC were administered to determine self-report measures of pain and disability. Speed, stride length, support time, knee angle, and peak vertical force (PVF) were determined from 3-dimensional kinematic and kinetic data collected on subjects walking at self-selected normal and fast speeds. Anthropometric data and radiographic levels of OA were also collected. Results: Pearson correlation analysis showed that the AIMS physical disability score was inversely correlated with speed, stride length, and knee range of motion at both speeds and PVF at the fast speed. The WOMAC function score was inversely correlated with speed and stride length at both speeds and with PVF at fast speed. The WOMAC pain score was inversely correlated with speed and PVF at the fast speed. Regression analysis revealed that the AIMS physical disability score and body mass index accounted for the greatest variation in speed at the normal speed. Overall, AIMS physical disability and WOMAC function explained a larger proportion of variance in gait mechanics than radiographic measures of OA disease severity. Conclusions: Taken together, the results suggest that the AIMS physical disability and WOMAC function scores are associated with some important measures of gait impairment.