Modulation of the Relationship Between External Knee Adduction Moments and Medial Joint Contact Forces Across Subjects and Activities

Abstract

ObjectiveThe external knee adduction moment (EAM) is often considered a surrogate measure of the distribution of loads across the tibiofemoral joint during walking. This study was undertaken to quantify the relationship between the EAM and directly measured medial tibiofemoral contact forces (Fmed) in a sample of subjects across a spectrum of activities.MethodsThe EAM for 9 patients who underwent total knee replacement was calculated using inverse dynamics analysis, while telemetric implants provided Fmed for multiple repetitions of 10 activities, including walking, stair negotiation, sit-to-stand activities, and squatting. The effects of the factors “subject” and “activity” on the relationships between Fmed and EAM were quantified using mixed-effects regression analyses in terms of the root mean square error (RMSE) and the slope of the regression.ResultsAcross subjects and activities a good correlation between peak EAM and Fmed values was observed, with an overall R2 value of 0.88. However, the slope of the linear regressions varied between subjects by up to a factor of 2. At peak EAM and Fmed, the RMSE of the regression across all subjects was 35% body weight (%BW), while the maximum error was 127 %BW.ConclusionThe relationship between EAM and Fmed is generally good but varies considerably across subjects and activities. These findings emphasize the limitation of relying solely on the EAM to infer medial joint loading when excessive directed cocontraction of muscles exists and call for further investigations into the soft tissue–related mechanisms that modulate the internal forces at the knee.

Medial and lateral foot loading and its effect on knee joint loading

“…The first peak of the EAM during the stance phase was [16,17]. One of the reasons seems to be that antagonistic muscle activities, which raise the joint contact force, are not reflected in gait analysis data.…”

Are Instrumented Knee Forces Representative of a Larger Population of Cruciate-Retaining Total Knee Arthroplasties?

“…The study also identified strategies for proper tuning of this parameter which we used in this study [28]. Although previous investigations have found that the medial-lateral force ratio is correlated with the external knee adduction moment [23,29], it is uncertain as to whether this relationship holds true for all activities and whether it may be influenced by patient characteristics such as knee alignment [30,31]. Specifically, for chair sitting and rising the medial-lateral force ratio of 50%, indicating equal force transfer between the medial and lateral sides of the tibial plateau, was necessary to obtain forces with the computational model.…”

“…Specifically, for chair sitting and rising the medial-lateral force ratio of 50%, indicating equal force transfer between the medial and lateral sides of the tibial plateau, was necessary to obtain forces with the computational model. A previous study of instrument prostheses, although with a more constrained prosthesis design, also found the percentage of force transmitted medially through the knee to be lower for chair activities than stair and walking activities [32,31]. …”

Simulative Analysis of Joint Loading During Leg Press Exercise for Control Applications

“…1, right) sagittal plane frontal plane highlights a cause for a potential training-induced damage. High external knee adduction moments reflect high compressive forces acting on the medial knee compartment (Kutzner et al (2013)) and are supposed to foster osteoarthritis (OA) development and progression, when occurring during locomotion (Reeves and Bowling (2011), Andriacchi et al (2004), Trepczynski et al (2014)). Thus, training in the leg press with OA patients and elderly people should focus to reduce knee adduction moments.…”