Locking vs. non-locking plate fixation in comminuted talar neck fractures: a biomechanical study using cadaveric specimens

Background

Talar neck fractures are rare but potentially devastating injuries, with early reduction and rigid fixation essential to facilitate union and prevent avascular necrosis. Even small degrees of malunion will alter load transmission and subtalar joint kinematics. Changes in fixation techniques have led to dual plating strategies. While locked plating has perceived advantages in porotic bone and comminution, its biomechanical benefits in talar neck fractures have not been shown.

Aim

To compare the strength of locking vs. non-locking plate fixation in comminuted talar neck fractures.

Method

Seven pairs of cadaveric tali were randomised to locking or non-locking plate fixation. A standardised model of talar neck fracture with medial comminution was created, and fixation performed. The fixed specimens were mounted onto a motorised testing device, and an axial load applied.

Results

Peak load to failure, deformation at failure, work done to achieve failure, and stiffness of the constructs were measured. No statistically significant difference was found between locking and non-locking constructs for all parameters.

Conclusions

Both constructs provide similar strength to failure in talar neck fracture fixations. Mean peak load to failure did not exceed the theoretical maximum forces generated of 1.1 kN when weight-bearing. We would advocate caution with early mobilisation in both fixations.