Development of an Impulse Response Method for Assessing Knee Osteoarthritis at the Femorotibial Joint: Comparison Between Healthy Young Adults and Older Women with Clinical Knee Osteoarthritis

Abstract

Because in patients with knee osteoarthritis (OA), the knee joint properties such as cartilage, meniscus, soft tissue and bone formation are assumed to degeneration change, the shock absorb might also decrease. The transmission of impulse from femur and tibia is thought to change in the knee joint. The purpose of the present study was to determine the differences between young healthy women and elderly women with knee OA using the impulse response method. Twenty-six older women with clinically diagnosed knee OA (OA group, age: 69 ± 6 years) and 26 young women without knee OA (young control [YC] group, age: 21 ± 1 years) participated in the study. The OA group fulfilled the knee OA classification criteria based on clinical findings. An input device provided an impulse to the subject while standing. The output value was measured using a single-axis accelerometer. The outcome measures were the input–output ratio and power spectrum. The input–output ratio did not significantly differ between the groups. The power spectrum at 21–30 Hz was significantly greater (p = 0.036) in the OA group than in the control group. Additionally, the power spectrum at 21–30 Hz correlated with knee pain (r = 0.39, p = 0.049). At 21–30 Hz, transmission of impulse from femur and tibia in the knee joint was lower in the OA group than in the control group. The IR method used in the present study could detect the transmission of impulse in early knee OA.