Minimal clinically important difference of the Japanese Lower Extremity Functional Scale in patients with hip osteoarthritis

Abstract

Objective: This study investigated the minimal clinically important difference (MCID) of the Japanese version of the Lower Extremity Functional Scale (LEFS) in patients with hip osteoarthritis to determine the index 3 months after the implementation of exercise therapy.

Materials and methods: The study included 69 patients diagnosed with hip osteoarthritis who visited our clinic between April 2022 and January 2023. The MCID was calculated using a distribution-based method by multiplying the standard deviation (SD) of the difference between before and 3 months after exercise therapy by 0.5. The effect size was calculated by dividing the difference between before and 3 months after exercise therapy by the SD.

Results: The MCID of the Japanese version of the LEFS 3 months after exercise therapy was 4.4 points. The proportion of patients reaching the MCID was 48%, and the effect size was 0.59.

Discussion: The MCID and effect size of the Japanese version of the LEFS indicate that it could provide an index of MCID.

Conclusion: The MCID of the Japanese LEFS in patients with hip osteoarthritis patients at 3 months after the implementation of exercise therapy was found to be 4.4 points.