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A Musculoskeletal-Finite Element Study of Knee Joint Loading and Cartilage Mechanics in Children with Cerebral Palsy
Dongfei Huo1, Run Lin1, Junyan Li2,3
1Department of Engineering, Faculty of Environment, Science and Economy, University of Exeter, Exeter, EX44QF, UK.
Insights
Children with cerebral palsy (CP) experience altered knee joint loading and higher cartilage pressures, especially in hemiplegia. This study used a musculoskeletal-finite element (MSK-FE) framework to analyze these biomechanical differences.
Area of Science:
- Biomechanics
- Orthopedics
- Pediatric Rehabilitation
Background:
- Cerebral palsy (CP) often leads to abnormal gait patterns.
- Abnormal gait can alter knee joint loading, potentially accelerating degeneration.
- Understanding these biomechanical changes is crucial for managing CP.
Purpose of the Study:
- To quantify differences in knee joint biomechanics between children with CP and typically developing (TD) peers.
- To utilize an integrated musculoskeletal-finite element (MSK-FE) framework for this analysis.
- To investigate subtype- and limb-specific loading patterns in CP.
Main Methods:
- Gait data from 13 children (5 TD, 4 hemiplegia [HP], 4 diplegia [DP]) were analyzed.
- OpenSim software was used to obtain knee kinematics and forces.
- 3D finite element (FE) knee models were created and loaded with gait data to evaluate cartilage pressures.
Main Results:
- Children with CP (HP and DP) showed increased knee flexion compared to TD peers.
- The unaffected limb in HP (HP_UA) exhibited compensatory overloading with the highest peak knee joint reaction forces (KJRFs).
- Peak cartilage contact pressures were significantly higher in HP cohorts and slightly higher in DP compared to TD, with HP_UA showing the highest pressures.
Conclusions:
- The MSK-FE framework effectively quantified knee loading and cartilage pressure patterns in children with CP.
- Findings highlight distinct gait-loading patterns specific to CP subtypes and limbs.
- These results provide a foundation for future research on CP management and interventions.
Purpose:
Cerebral palsy (CP) is typically associated with abnormal gait that may alter knee joint loading and accelerate joint degeneration. We developed an integrated musculoskeletal-finite element (MSK-FE) framework to quantify differences in knee joint biomechanics between children with CP and typically developing (TD) peers.
Methods:
Gait data from 13 children (TD, n = 5; hemiplegia [HP], n = 4; diplegia [DP], n = 4) were analyzed using OpenSim to obtain knee kinematics and compressive knee joint reaction forces (KJRFs). These were applied to scaled 3D FE knee models, incorporating biphasic cartilage, menisci, and ligaments, at the first force peak, mid-stance, and second force peak to evaluate cartilage pressures.
Results:
Compared with TD, both CP subtypes (HP and DP) exhibited greater knee flexion throughout the gait cycle, except for the affected limb in HP (HPA), which showed reduced flexion during the stance phase. Peak KJRFs over the gait cycle were slightly higher in DP and HPA than in TD, whereas the unaffected limb in HP (HPUA) generated the highest peak KJRFs among all groups, indicating compensatory overloading of the unaffected limb in HP. Correspondingly, FE analysis showed that peak cartilage contact pressures in the HP cohorts were significantly higher than in DP and TD, while pressures in DP were slightly higher than in TD over the gait cycle. The HPUA showed the highest contact pressures among all groups.
Conclusion:
The MSK-FE framework quantified knee loading and cartilage contact pressure patterns in children with CP. These preliminary findings highlight subtype- and limb-specific gait-loading patterns and provide a mechanistic basis for future larger-scale and longitudinal investigations.
