Identifying Activity Limitation and Decline in Quality of Life in Patients with Knee Osteoarthritis Who Are Scheduled to Undergo Total Knee Arthroplasty.

This study examines factors associated with activity limitation and the decline in quality of life in patients with knee osteoarthritis (OA), and to determine standard values that would be useful for understanding the disease state. We assessed individual factors, the modified version of the Self-Rating Frenchay Activities Index (SR-FAI), and the Japanese Knee Osteoarthritis Measure (JKOM) of 661 participants. Multiple regression analyses were used to examine the relationship between dependent and explanatory variables. Standard values were calculated after stratifying based on factors related to each dependent variable through multiple regression analyses. Among the participants aged 60-74/75-89 years, the standard values for the modified SR-FAI were 23/19 and 20/18 points for K-L grades III and IV in the males, and 29/23 and 26/21 points in the females, respectively. The standard values for the JKOM were 35/49 and 45/59 points for K-L grades III and IV in the males and 41/52 and 47/60 points in the females, respectively. These standard values are a useful index for interpreting the degree of activity limitation and satisfaction reduction in patients with knee OA, and could help in clinical decision making for healthcare providers.