Open AccessKnee joint loading differs in individuals with mild compared with moderate medial knee osteoarthritis
Author(s) -
Thorp Laura E.,
Sumner D. Richman,
Block Joel A.,
Moisio Kirsten C.,
Shott Susan,
Wimmer Markus A.
Publication year - 2006
Publication title -
arthritis & rheumatism
Language(s) - English
Resource type - Journals
eISSN - 1529-0131
pISSN - 0004-3591
DOI - 10.1002/art.22247
Subject(s) - osteoarthritis , medicine , knee joint , asymptomatic , radiography , gait , orthodontics , gait analysis , physical therapy , physical medicine and rehabilitation , surgery , pathology , alternative medicine
Objective To compare the knee joint loading patterns in individuals with differing radiographic grades of knee osteoarthritis (OA) for characterization of the mechanical implications of different structural states, and to compare the knee adduction angular impulse, a measure of gait complementary to the commonly used peak knee adduction moment. Methods Asymptomatic subjects (those without knee OA) having a Kellgren/Lawrence (K/L) radiographic severity grade of 0 or 1 (n = 28) and subjects with symptomatic knee OA having K/L grades of 2 (n = 66) or 3 (n = 23) were recruited. Gait analysis was used to calculate the peak external knee adduction moment and the external knee adduction angular impulse for the whole stance and for the 4 subdivisions of stance. Results Both the peak knee adduction moment and the knee adduction angular impulse increased with K/L radiographic grade ( P < 0.05). However, only the knee adduction angular impulse differed between subjects with moderate (grade 3) and those with mild (grade 2) radiographic knee OA ( P < 0.05). Conclusion The differences between mild and moderate symptomatic radiographic knee OA are not only structural but also functional, based on the magnitude of load in the medial knee joint. Moreover, knee adduction angular impulse provides additional information beyond that available from the peak knee adduction moment, and may therefore be an important gait parameter to include in OA research. These findings are important for our understanding of the pathophysiologic mechanisms of OA.