Finite element analysis of hip joint stress distribution based on CT imaging in marathon runners during the gait cycle / 中华放射学杂志

ABSTRACT

Objective:To explore the distribution of perihip stress in male marathon runners and normal volunteers during the gait cycle using finite element analysis.Methods:In November 2022, the hip joint CT image data of a male marathon runner and a male healthy volunteer was collected. The gait cycle was divided into 7 phases, including the foot to the ground, the early, middle, and late period of one-foot support, the toe push and extension period, and the beginning and end of the swing. A three-dimensional finite element model was constructed based on the gray value of CT and according to the individualized material attribute assigning scheme. The dynamic change of hip joint contact force during the gait cycle was applied to the load, and the biomechanical qualitative analysis of the model was carried out through the equivalent stress results. Based on qualitative analysis, the same 10 nodes on the front, middle, and back of the model acetabulum, the front, and back of the femoral head, and the neck of the femur were extracted as equivalent stress reference points, and the biomechanical quantitative analysis of the model was carried out.Results:During the gait cycle, according to the hip equivalent stress distribution diagram, the contact on the articular surface of the two subjects mainly occurred in the posterior upper part of the acetabulum and the posterior part of the femoral head and gradually moved outward and backward with the joint force during walking. From the point of view of the stress distribution nodes around the hip joint, the stress changes of the nodes in each part of the two subjects showed bimodal characteristics with the load inside the hip joint at each phase. The internal stress value of the hip joint showed a gradual upward trend from the foot to the ground, reached the maximum stress in the middle period of one-foot support, then decreased, and slightly increased in the toe push and extension period. Then, the stress values at the beginning and end of the swing gradually decreased until entering the next gait cycle. The stress values in the posterior acetabulum and posterior femoral head of the marathon runner were smaller than those of the healthy volunteer.Conclusion:The stress around the hip joint was different between marathon runner and healthy volunteer, but the stress distribution and transmission path were the same.