Three-dimensional finite element analysis on splint fixation for treating ulnar styloid process fracture / 中国组织工程研究

ABSTRACT

BACKGROUND: Distal radius fractures are often accompanied by the ulna styloid process fractures, and the treatment of the ulna styloid process fracture is disputed in clinic. Manipulative reduction and splint fixation is a common method to treat such diseases. The mechanism of intervention on ulnar styloid process is difficult to obtain in the corpse mechanics experiments. In recent years, the finite element analysis method has been widely used in the field of orthopedics, which has opened up a way for the study of orthopedic disease. OBJECTIVE: To explore the biomechanical mechanism of splint intervention on ulnar styloid fracture by finite element analysis, and to provide the basis for clinical treatment choice. METHODS: A three-dimensional finite element model of normal wrist joint was established based on the forearm and wrist CT images of a healthy volunteer. The validity of the model was verified by comparing with the experimental data in the literature. On this basis, four wrist joint finite element models with and without splint fixation for ulnar styloid type I and type II fractures were established. Under axial compression, lateral extension, pronation and supination working conditions, the changes of the relative displacement of the distal radioulnar joint and the ulnar styloid fracture broken end were analyzed. RESULTS AND CONCLUSION: (1) A three-dimensional finite element model of normal wrist joint was established and validated, and the other four models were established based on this model. (2) In pronation and supination conditions, the relative displacement values of the ulnar and radial joints in the ulnar styloid type I and II fracture models were greater than those in the normal wrist joint model, and the displacement was smaller in the type I fracture model than in the type II fracture model; the displacement was significantly reduced after the intervention on the two fracture models by the splint. (3) In the lateral tension, pronation and supination conditions, the displacement values of the ulnar styloid fracture end in the ulnar styloid type I fracture model were smaller than in the type II fracture model, and the displacement values were significantly reduced after the intervention by the splint. Under the remaining conditions, the change of the above values was not obvious. (4) In conclusion, the stability of distal radioulnar joint became worse after ulnar styloid fracture, and the stability of distal radioulnar joint after type I fracture was less than that after type II fracture. As an elastic fixation method, splint can increase the stability of the wrist ulnar column during the treatment.