RESUMO
BACKGROUND:At present,wrist protection products designed in and outside China have not solved the contradiction between protecting the wrist joint from injury and maintaining the flexible movement of the wrist joint. OBJECTIVE:To investigate the biomechanical mechanism of dorsiflexion injury of the wrist joint in elderly people after falls,and to provide a biomechanical basis for the prevention and treatment of wrist injury in elderly people after falls. METHODS:A 65-year-old man was selected to obtain the original data by uninterrupted CT scan of the middle and lower 2/3 of his left forearm up to the end of the finger.A finite element model of wrist dorsiflexion was established using ANSYS 12.0 finite element software.The palm surface of the model was constrained,and the model at a velocity load of 2 m/s in the direction of vertical downward was given to simulate the injury state of the palm when the elderly fall.The stress distribution of the soft tissues and bones of the wrist joint and the change of the stress with time were observed after the load was applied. RESULTS AND CONCLUSION:(1)A realistic and effective finite element model of the dorsal extension position of the wrist joint of the elderly was established.The soft tissue stresses were mainly concentrated in the small fissure of the palm and the dorsal side of the wrist after loading.The skeletal stresses were mainly concentrated in the lower end of the ulnar radius dorsally.The stresses in the lower end of the radius were the greatest.The palmar stresses were mainly concentrated in the middle and lower 1/3 of the radius and the hook bone.The stress distribution of the ulnar radius was asymmetric,and the stresses in the radius were more concentrated.(2)The results of the study are consistent with the clinical situation of a fallen wrist injury in elderly people,and can be used to explain the mechanism of wrist dorsiflexion injury,which can provide the biomechanical basis for the design of wrist protection devices that can be used to prevent wrist injury induced by falling and the treatment of wrist injury in elderly people.