A finite element analysis was conducted on the biomechanics of the locking plate and intramedullary nail fixation for the treatment of distal tibial fractures, and the results were verified combined with clinical cases, so as to provide references for clinical treatment.

(1) Finite element analysis: the three-dimensional CT data of the lower limbs of a healthy male volunteer were used to establish a finite element model. The internal stress distribution of the tibial plateau was set to 60% of the total load by intramedullary nail and locking plate respectively, and the tibia end was fixed effectively. 400 N axial pressure load which equaled to that of adult knee joint during single axis standing was simulated. The equivalent stress and displacement of the model by different fixations were compared.(2) Clinical verification: a retrospective case control study was performed on the clinical data of 37 cases of distal tibial fractures treated with internal fixation from June 2015 to December 2016, including 17 cases in intramedullary nail group and 20 in locking plate group. The operation time, intraoperative blood loss, postoperative fracture healing time, and postoperative Johner-Wruhs score of patients were recorded for comprehensive assessment of recovery.

(1) The finite element analysis results: the maximum stress value was 5.907 MPa for intramedullary nail and 5.821 MPa for locking plate model(P>0.05), respectively. The maximum displacement of intramedullary nail model was 2.313 mm, lower than that of locking plate fixation system (3.854 mm)(P<0.05). (2) Clinical verification: the operation time and intraoperative blood loss of intramedullary nail were both lower than those of locking plate [(114.1±21.6)minutes) ∶ (129.8±21.4)minutes and (152.9±64.88)ml ∶ (212.5±98.5)ml] (P<0.05). The average fracture healing time was (17.7±2.8)weeks for intramedullary nail and (20.6±4.1) weeks for locking plate (P<0.05), respectively. In the intramedullary nail group, the Johner Wruhs score was excellent in 13 cases and good in four cases, with excellent and good rate of 100%, while in the locking plate group, nine cases were excellent, eight were good, and three were fair, with excellent and good rate of 85% (P>0.05).

In terms of biomechanics and clinical effect, intramedullary nail fixation is superior than the medial locking plate fixation for the treatment of the distal tibial fractures. Intramedullary nail fixation can reduce surgical trauma and bone displacement after fixation and promote fracture healing.

Tibial fractures; Finite element analysis; Intramedullary nail