Abstract:

BACKGROUND: In the calcaneal fractures, proper treatment can significantly improve prognosis of the patients.
OBJECTIVE: To analyze the effect of multi-pin fixation and plate fixation on calcaneal fractures, and to evaluate clinical efficacy of two kinds of internal fixation methods.
METHODS: ①CT scan was performed on a normal male right calcaneus to establish a complete three-dimensional finite element model of calcaneus, and the model was used to simulate Sanders Ⅱ type fracture of calcaneus, and simulate the tendon loading condition after calcaneal fracture plate and multi-pin internal fixation. The stress distribution, the relative displacement of the fracture line and the maximum principal stress of internal fixation of three groups (plate functional location at 0°; multi-pin functional location at 0°; multi-pin planter flexion location at 30°) were comparatively analyzed. ②Retrospective study of 59 cases of Sanders Ⅱ type fracture, 36 cases of the foot treated with open reduction and multi-pin fixation, 23 cases of the foot treated with open reduction and plate fixation, then the soft tissue complications after fixation was evaluated.
RESULTS AND CONCLUSION: ①The finite element analysis showed the biggest achilles tendon loading load was 160 N, the maximum principal stress values of the models in three groups were less than the yield strength of fixation 225 MPa. The relative displacement of calcaneal fracture line in three groups was less than the intra-articular calcaneal fractures indications standard (surgical separation of the fracture line or displacement ≥ 1 mm). Continuous loading 1- 1 000 N load condition, the achilles tendon loads of internal fixation failure in three groups were greater than 160 N. Stress distribution analysis showed multi-pin and plate fixation evenly distributed the stress. ②The clinical research results showed that good rate of Sanders Ⅱ fracture in multi-pin fixation group was more than 83%, the good rate in the plate fixation group was 78%, there was no significant difference of the efficacy after fixation between two groups (P > 0.05). The occurrence rate of postoperative soft tissue complications in multi-pin fixation group was lower than that in the plate fixation group (P < 0.05).