Large-scale subject-specific finite element knee modeling with direct integration of limb alignment and length

Finite element (FE) modeling is widely used to study knee joint mechanics and pathologies. Subject-specific FE models provide individualized insight into knee mechanics but are often limited to small-scale studies due to complexity and time constraints. Hip-knee-ankle (HKA) angle and limb length influence joint loading and osteoarthritis risk, yet are rarely incorporated into FE models without motion-capture data and full lower-body musculoskeletal modeling. This study presents an efficient approach for large-scale subject-specific FE knee modeling that directly integrates HKA and limb length. Subject-specific FE models were generated for 625 participants, resulting in 2,500 FE simulations across four model variations per knee. Joint mechanics were evaluated during the stance phase of gait. HKA strongly influenced medial-lateral load distribution, with varus and valgus alignments shifting the load toward the medial and lateral compartments, respectively. Femoral length also altered joint loads in both the tibiofemoral and patellofemoral joints, leading to corresponding changes in cartilage stress. These findings demonstrate that limb alignment and length both play important roles in knee mechanics and can be implemented into FE knee models without full musculoskeletal simulations. The proposed framework enables efficient large-scale FE modeling for applications such as surgical planning, implant design, and osteoarthritis research.