Bilateral knee-load limiting during uneven-terrain walking induces hip-dominant load redistribution in predictive gait simulations

BackgroundKnee pain may induce protective gait patterns that reduce knee loading, but the multi-joint trade-offs that emerge under uneven-terrain demands remain uncertain.MethodsUsing SCONE/Hyfydy, we generated sagittal-plane predictive simulations over a deterministic ten-tile terrain sequence. A reflex-based controller was optimized under no knee-load limit (C0) or bilateral soft limits of 4, 3, or 2 body weights (C4, C3, and C2). We retained the lowest-objective solution from 24 runs per condition and reanalyzed every complete stance within 1–12 s by limb and terrain.ResultsThe C0 knee joint-reaction-force peaks of 8.35/8.25 BW (left/right) occurred during early stance on tile 9 (−4°) and tile 10 (−2°), respectively. The left peak arose in a stance confined to tile 9, whereas the right peak arose in a stance that crossed the tile 9-to-10 boundary; neither occurred during initialization. Corresponding maxima were 4.51/4.34 BW in C4, 3.63/3.71 BW in C3, and 3.60/3.73 BW in C2. Mean stance impulse decreased from 2.14/2.00 BW·s in C0 to 1.79/1.82, 1.65/1.69, and 1.58/1.59 BW·s in C4, C3, and C2, respectively. Evaluation-window mean hip loading increased and speed decreased, whereas initial loading rate did not change monotonically. The selected solution ranked first by objective in every condition; 5–17 of 24 runs were within 10% of the selected objective.ConclusionWithin this model, controller, weighting scheme, and single terrain traversal, knee-load limiting was associated with slower walking, lower stance-phase knee peaks and impulses, and hip-dominant redistribution. These results are scenario-specific model behaviors rather than direct clinical predictions.