Multi-pin Internal Fixation Of Calcaneal Fractures In Finite Element Analysis

Objective:Aimed at the analysis of calcaneal fractures of multi-pin fixation and plate fixation of the two methods of fixed effects, evaluation of two kinds of internal fixation methods in clinical efficacy, for the treatment of calcaneal fracture select the internal fixation methods provide the biomechanical evidence, for the clinical treatment of calcaneal fractures provide guiding significance.Method: Retrospective study of 59 cases of intra-articular calcaneal fractures, Sanders points:Ⅱtype 59 cases, 36 cases of the foot with open reduction and Multi-pin fixation, 23 cases of the foot open reduction and plate fixation, evaluation of two kinds of plate and multi-pin internal fixation of clinical efficacy.CT scan of a weight 64kg normal male right calcaneus, establishment of a complete three-dimensional finite element model calcaneus, simulation of SandersⅡtype fracture of calcaneus, simulation of calcaneal fracture plate and multi-pin of two kinds of internal fixation by Achilles tendon loading condition, comparative study of model of stress distribution and the relative displacement of the fracture line. Results(:1)The clinical results: SandersⅡfracture Multi-pin fixation group good rate of more than 83%. Plate group good rate of 78%, The two groups after the efficacy of no statistical difference (P>0.05). Postoperative soft tissue complications of Multi-pin fixation group the occurrence rate of 16.7%, Plate fixation group the occurrence rate of 34.8%, The difference was statistically significant (P<0.05). (2)The finite element results: The biggest Achilles tendon loading load 160 Newtons of three groups of fracture fixation model group, The functional position of 0°within the group of plate fixed maximum principal stress values: 85.452MPa, Multi-pin functional position 0°within the group of fixed maximum principal stress values: 87.378MPa, Multi-pin 30°plantar flexion group fixed the maximum principal stress value: 120.58MPa. three groups of the model fixed the maximum principal stress values are less than the yield strength of fixation of 225MPa. Three models of the relative displacement calcaneal fracture line is less than the intra-articular calcaneal fractures are indications for surgical separation of the fracture line or displacement of≥1mm requirements. Continuous loading 1 to 1000 Newtons load condition, When internal fixation failure in internal fixation of three groups of corresponding maximum principal stress values of the Achilles tendon loading respectively: Plate function position 0°group: 487.38 N; multi-pin functional position 0°group:465.45 N; multi-pin 30°plantar flexion group: 340.28 N. Three groups of models of internal fixation failure in the Achilles tendon loads were greater than 160 N. From inside the fixed stress distribution analysis, multi-pin and plate fixation are evenly distributed the stress.Conclusion: For SandersⅡtype of intra-articular calcaneal fractures, plate internal fixation with multiple pin fixation can obtain similar clinical efficacy and the result of finite element analysis. Compared with plate fixation, multi-pin fixation is more suitable for SandersⅡfracture, and can effectively reduce the risk of postoperative soft tissue complications.