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The gait modification strategies Trunk Lean and Medial Thrust have been shown to reduce the external knee adduction moment (EKAM) in patients with knee osteoarthritis which could contribute to reduced progression of the disease. Which strategy is most optimal differs between individuals, but the underlying mechanism that causes this remains unknown. Which gait parameters determine the optimal gait modification strategy for individual patients with knee osteoarthritis? Forty-seven participants with symptomatic medial knee osteoarthritis underwent 3-dimensional motion analysis during comfortable gait and with two gait modification strategies: Medial Thrust and Trunk Lean. Kinematic and kinetic variables were calculated. Participants were then categorized into one of the two subgroups, based on the modification strategy that reduced the EKAM the most for them. Multiple logistic regression analysis with backward elimination was used to investigate the predictive nature of dynamic parameters obtained during comfortable walking on the optimal modification gait strategy. For 68.1 % of the participants, Trunk Lean was the optimal strategy in reducing the EKAM. Baseline characteristics, kinematics and kinetics did not differ significantly between subgroups during comfortable walking. Changes to frontal trunk and tibia angles correlated significantly with EKAM reduction during the Trunk Lean and Medial Thrust strategies, respectively. Regression analysis showed that MT is likely optimal when the frontal tibia angle range of motion and peak knee flexion angle in early stance during comfortable walking are high (R2 Nagelkerke = 0.12). Our regression model based solely on kinematic parameters from comfortable walking contained characteristics of the frontal tibia angle and knee flexion angle. As the model explains only 12.3 % of variance, clinical application does not seem feasible. Direct assessment of kinetics seems to be the most optimal strategy for selecting the most optimal gait modification strategy for individual patients with knee osteoarthritis. • Self-selected Trunk Lean modification reduces the EKAM more than Medial Thrust. • The degree of frontal tibia angle modifications may determine the optimal strategy. • Parameters during comfortable walking only moderately predict the optimal strategy. [ABSTRACT FROM AUTHOR]

Objective: To determine (1) if Medial Thrust or Trunk Lean reduces the knee adduction moment (EKAM) the most during gait in patients with medial knee osteoarthritis, (2) if the best overall strategy is the most effective for each patient and (3) if these strategies affect ankle and hip kinetics.Design: Thirty patients with symptomatic medial knee osteoarthritis underwent 3-dimensional gait analysis. Participants received verbal instructions on two gait strategies (Trunk Lean and Medial Thrust) in randomized order after comfortable walking was recorded. The peaks and impulse of the EKAM and strategy-specific kinematic and kinetic variables were calculated for all conditions.Results: Early stance EKAM peak was significantly reduced during Medial Thrust (-29%). During Trunk Lean, early and late stance EKAM peak and EKAM impulse reduced significantly (38%, 21% and -25%, respectively). In 79% of the subjects, the Trunk Lean condition was significantly more effective in reducing EKAM peak than Medial Thrust. Peak ankle dorsi and plantar flexion, knee flexion and hip extension and adduction moments were not significantly increased.Conclusions: Medial Thrust and Trunk Lean reduced the EKAM during gait in patients with knee osteoarthritis. Individual selection of the most effective gait modification strategy seems vital to optimally reduce dynamic knee loading during gait. No detrimental effects on external ankle and hip moments or knee flexion moments were found for these conditions. [ABSTRACT FROM AUTHOR]

Knee contact pressure is a crucial factor in the knee rehabilitation programs. Although contact pressure can be estimated using finite element analysis, this approach is generally time-consuming and does not satisfy the real-time requirements of a clinical set-up. Therefore, a real-time surrogate method to estimate the contact pressure would be advantageous. This study implemented a novel computational framework using wavelet time delay neural network (WTDNN) to provide a real-time estimation of contact pressure at the medial tibiofemoral interface of a knee implant. For a number of experimental gait trials, joint kinematics/kinetics and the resultant contact pressure were computed through multi-body dynamic and explicit finite element analyses to establish a training database for the proposed WTDNN. The trained network was then tested by predicting the maximum contact pressure at the medial tibiofemoral knee implant for two different knee rehabilitation patterns; “ medial thrust ” and “ trunk sway ”. WTDNN predictions were compared against the calculations from an explicit finite element analysis (gold standard). Results showed that the proposed WTDNN could accurately calculate the maximum contact pressure at the medial tibiofemoral knee implant for medial thrust ( R M S E ¯ =1.7 MPa, N R M S E ¯ =6.2% and ρ ¯ =0.98) and trunk sway ( R M S E ¯ = 2.6 MPa, N R M S E ¯ =9.3%, ρ ¯ =0.96) much faster than the finite element method. The proposed methodology could therefore serve as a cost-effective surrogate model to provide real-time evaluation of the gait retraining programs in terms of the resultant maximum contact pressures. [ABSTRACT FROM AUTHOR]

Background The progression of medial knee osteoarthritis seems closely related to a high external knee adduction moment, which could be reduced through gait retraining. We aimed to determine the retraining strategy that reduces this knee moment most effective during gait, and to determine if the same strategy is the most effective for everyone. Methods Thirty-seven healthy participants underwent 3D gait analysis. After normal walking was recorded, participants received verbal instructions on four gait strategies (Trunk Lean, Medial Thrust, Reduced Vertical Acceleration, Toe Out). Knee adduction moment and strategy-specific kinematics were calculated for all conditions. Findings The overall knee adduction moment peak was reduced by Medial Thrust (− 0.08 Nm/Bw·Ht) and Trunk Lean (− 0.07 Nm/Bw·Ht), while impulse was reduced by 0.03 Nms/Bw·Ht in both conditions. Toeing out reduced late stance peak and impulse significantly but overall peak was not affected. Reducing vertical acceleration at initial contact did not reduce the overall peak. Strategy-specific kinematics (trunk lean angle, knee adduction angle, first peak of the vertical ground reaction force, foot progression angle) showed that multiple parameters were affected by all conditions. Medial Thrust was the most effective strategy in 43% of the participants, while Trunk Lean reduced external knee adduction moment most in 49%. With similar kinematics, the reduction of the knee adduction moment peak and impulse was significantly different between these groups. Interpretation Although Trunk Lean and Medial Thrust reduced the external knee adduction moment overall, individual selection of gait retraining strategy seems vital to optimally reduce dynamic knee load during gait. [ABSTRACT FROM AUTHOR]