Knee joint loading differs in individuals with mild compared with moderate medial knee osteoarthritis

Abstract

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.The peak external joint moments determined by gait analysis are surrogate markers of the effects of contact load on an individual's joints. In particular, in the knee, the external adduction moment is the primary predictor of load distribution across the tibial plateau (1) and is a main determinant of clinical outcomes following surgical intervention to correct varus deformity (2). Individuals with symptomatic radiographic knee osteoarthritis (OA) have higher-than-normal peak external knee adduction moments during walking (3-8).The peak external knee adduction moment has been implicated in progression of radiographic OA (9) and has been identified as a marker of disease severity (8,10), when individuals with OA radiographic severity grades Յ2 are compared with those with grades Ն3, using the Kellgren and Lawrence (K/L) scale (11). In addition, when the first and second peak external knee adduction moments, occurring during midstance and terminal stance, respectively, were compared in healthy controls and in individuals with less or more severe OA, the first peak was higher than normal regardless of disease severity, whereas the second peak was higher than normal only in those with more severe OA (8).As a measure of knee load, the peak external knee adduction moment reflects only a single time point during stance and is independent of the duration of the stance phase of gait. Because individuals with OA ambulate at slower speeds (3) and exhibit a prolonged stance phase as compared with hea...

Lateral Wedge Insoles for Reducing Biomechanical Risk Factors for Medial Knee Osteoarthritis Progression: A Systematic Review and Meta‐Analysis

“…The EKAM has been used as a proxy for medial knee joint load, and a reduction in the EKAM represents a change in medial to lateral distribution and a relative lowering of the medial compartment load (9). The area underneath the EKAM curve, the knee adduction angular impulse (KAAI), represents the cumulative effect of the EKAM over the stance phase (10). High medial knee loading during walking estimated using the EKAM and KAAI is predictive of structural progression in knee OA (3,5,6), under the tenet that high knee loading in the presence of established disease overwhelms the normal regulation of healthy tissue, precipitating ongoing structural change (11).…”

Trunk lean gait modification and knee joint load in people with medial knee osteoarthritis: The effect of varying trunk lean angles

“…The external KAM is a reliable and valid indicator of medial knee load (11,12) and is most often quantified by evaluating the 2 peaks during stance, as well as the impulse (area under the KAM-time curve). The first and typically largest peak occurs during the load acceptance phase of gait (approximately 25% stance), and the second peak occurs during the propulsion phase (approximately 75% stance) (13)(14)(15). Clinical implications of a large KAM are significant as the peak KAM is a strong predictor of medial compartment OA radiographic disease severity (16), rate of disease progression (6), and development of chronic knee pain (17).…”

Effects of Arm Swing Limitation on Knee Joint Moment during Walking —Biomechanical Analysis Using a 3D Motion Capture System—

“…This shows that when arm swing range is small, the dynamic load in the frontal plane decreases. Kito 5) and others 10,11) reported that the internal knee abduction moment of patients with knee OA is larger than that of healthy individuals during the stance phase. This suggests that patients with the knee OA have a smaller arm swing range in order to avoid pain.…”