Relation between knee joint deformity and gait in community-dwelling elderly people

Objectives: To clarify the relationship between the severity of knee deformity and gait. Methods: The subjects were 2,284 randomly-selected, communitydwelling middle-aged and elderly people ≥40 years old (men 1,154, women 1,130, mean age 60.2). They were classified into 3 groups by knee deformity on Xp: normal, mild, and severe. Gait velocity, pitch, and step length were examined by gait analysis at comfortable and maximum speeds. A general linear model adjusted for age, weight, and leg length was then used to investigate differences by severity of knee deformity. Results: The velocity of gait with comfortable speed in the normal, mild, and severe deformity groups was 85.5, 85.2, 81.7 (m/min), respectively, in men, and 82.0, 82.4, 79.5 (m/min) in women. It was significantly slower in the severe group than in the normal and mild groups in both sexes (all p < 0.05). In gait with maximum speed a similar difference was seen only in women (p < 0.05 and p < 0.01, respectively). Pitch was not significantly different between the groups in either gait with comfortable or maximum speed. Step length in gait with maximum speed was different between the severe and mild groups in both sexes and between the severe and normal groups in men (all p < 0.05). Maximum step length was significantly longer in the severe group than the normal and mild groups in both sexes (men, all p < 0.05; women, all p < 0.01). Conclusion: Severe knee deformity affects gait velocity, mainly by decreasing step length.