Physical performance and knee osteoarthritis among community-dwelling women in Japan: the Hizen-Oshima Study, cross-sectional study

Osteoarthritis (OA) is the most common chronic joint disorder. Relationships between knee OA and physical performance have been examined, but mainly in patients with knee OA. Clarifying the relationship between knee OA and physical performance among community-dwelling individuals is thus important. Subjects comprised 563 community-dwelling Japanese women. Radiographic knee OA was defined as Kellgren-Lawrence criteria grade 2 or higher. Painful knee OA was defined as radiographic OA combined with knee pain. We evaluated performance-based measures of physical functioning. Student's t tests were used to compare continuous variables. Adjusted means of performance-based measures were compared between groups using general linear modeling methods. Mean age was 64.3 years. Women with radiographic OA were older than those without OA (P < 0.0001). BMI was greater in women with radiographic OA than in women without OA (P < 0.0001). In univariate analysis, women with radiographic OA displayed worse physical functioning than women without OA, with longer chair stand time, longer walking time, and shorter functional reach. Performance-based measurements with painful OA resembled those with radiographic OA. Age- and BMI-adjusted means of chair stand time and walking time were longer in women with radiographic or painful knee OA than in women without OA (P < 0.0001 each). Furthermore, chair stand and walking took longer for women with painful knee OA than for women with radiographic knee OA. Women with knee OA showed deteriorated performance of chair stand and walking. Painful knee OA was associated with poorer performance than radiographic knee OA.