Comparison between external locking plate fixation and conventional external fixation for extraarticular proximal tibial fractures: a finite element analysis

Abstract

Background Good clinical outcomes for locking plates as an external fixator to treat tibial fractures have been reported. However, external locking plate fixation is still generally rarely performed. This study aimed to compare the stability of an external locking plate fixator with that of a conventional external fixator for extraarticular proximal tibial fractures using finite element analysis. Methods Three models were constructed: (1) external locking plate fixation of proximal tibial fracture with lateral proximal tibial locking plate and 5-mm screws (ELP), (2) conventional external fixation of proximal tibial fracture with an 11-mm rod and 5-mm Schanz screws (EF-11), and (3) conventional external fixation of a proximal tibial fracture with a 7-mm rod and 5-mm Schanz screws (EF-7). The stress distribution, displacement at the fracture gap, and stiffness of the three finite element models at 30-, 40-, 50-, and 60-mm plate–rod offsets from the lateral surface of the lateral condyle of the tibia were determined. Results The conventional external fixator showed higher stiffness than the external locking plate fixator. In all models, the stiffness decreased as the distance of the plate–rod from the bone surface increased. The maximum stiffness was 121.06 N/mm in the EF-11 model with 30-mm tibia–rod offset. In the EF-7 model group, the maximum stiffness was 40.00 N/mm in the model with 30-mm tibia–rod offset. In the ELP model group, the maximum stiffness was 35.79 N/mm in the model with 30-mm tibia–plate offset. Conclusions Finite element analysis indicated that external locking plate fixation is more flexible than conventional external fixation and can influence secondary bone healing. External locking plate fixation requires the placement of the plate as close as possible to the skin, which allows for a low-profile design because the increased distance from the plate to the bone can be too flexible for bone healing. Further experimental mechanical model tests are necessary to validate these finite element models, and further biological analysis is necessary to evaluate the effect of external locking plate fixation on fracture healing.

Finite element analysis of titanium anatomic plate and titanium reconstructive plate for treatment of extra-articular fractures of the scapula

“…In recent years, with the development of computer image processing technology, finite element analysis has been applied to various fields, which has greatly promoted the development of bio-medicine [ 28 ]. The emergence of finite element analysis provides a new idea for the study of biomechanics.…”

Finite element analysis modeling of plates versus intramedullary nails in closed comminuted midshaft tibial fractures

“…These models were constructed using computer assisted design (CAD) and analyzed using FEA. They found higher stiffness in models with conventional external fixators [ 17 ].…”

Biomechanical study of the stiffness of the femoral locking compression plate of an external fixator for lower tibial fractures

“…Marti et al were the first to use an internally fixed tibial anatomic locking splint as an external fixator in 1984 to treat open fractures, infected bone discontinuity, septic arthritis and other related conditions [15,18]. Subsequent finite element analysis and biomechanical studies on the stability of LCP external fixators for tibial fractures have shown that LCP has good biomechanical stability as an external fixator [19][20][21][22][23][24][25][26]. At the same time, some scholars have also applied LCP in clinical practice to treat open tibial fractures and have obtained more satisfactory results in clinical practice [27][28][29][30][31][32][33].…”