External fixators versus titanium elastic nailing for distal diaphyseal-metaphyseal junction tibial fractures: A finite element biomechanical analysis.

BACKGROUND: Computer modeling combined with finite element analysis was employed to assess the mechanical stability of external fixators (EF) and titanium elastic nails (TEN) in fractures involving the distal diaphyseal-metaphyseal junction (DMJ) of tibia.

METHODS: Transverse and oblique fracture models at the distal DMJ were constructed using computed tomography (CT) data from an 11-year-old girl's tibia‌. Various fixation strategies were designed for comparison (EF and TEN with antegrade approach). Finite element analysis was utilized to evaluate the mechanical stability of various fixation techniques in the fracture models.

RESULTS: In both fracture models, EF exhibited superior rotational and bending stiffness compared to TEN, while the axial stiffness was lower than that of TEN. In the oblique fracture model, both TEN and EF demonstrated better rotational stiffness compared to the transverse fracture model, while their axial stiffness and bending stiffness were lower than those observed in the transverse fracture model. Although EF showed a decrease in bending stiffness in the oblique fracture model, it still outperformed TEN, even exceeding the bending stiffness of TEN in the transverse fracture model.

CONCLUSION: In clinical practice, postoperative weight-bearing restriction is a common treatment strategy, making rotational and bending stability of internal fixation particularly important. EF provide excellent rotational and bending stability in both transverse and oblique fractures, making them a reasonable option for the treatment of distal DMJ fractures of the tibia.

LEVEL OF EVIDENCE: Level III.