Reconstruction of a Bryan and Morrey type I capitellar fracture in a sawbone model with four different fixation devices: An experimental study

Abstract Background We evaluated 4 different fixation devices for the reconstruction of a standardised Bryan and Morrey capitellar shear fracture in a sawbone model. Outcome measurements were the quality of reduction, time for reconstruction and stability. Methods 80 standardised Bryan and Morrey type I fractures were created for 5 different orthopaedic surgeons in 80 sawbones. Each surgeon reconstructed 16 fractures with 2 mm K-wires, 3 mm Herbert screws, 2.7 mm AO screws and 2.2 mm fine-threaded wires (Fragment Fixation System: FFS). 4 fractures were allocated to each method with a standardised reconstruction procedure. Quality of reduction and time for reconstruction were measured after definitive fixation. Biomechanical testing was performed using a shear loading model with the application of monocyclic or polycyclic stress to the reconstructed capitulum. Results There was no difference in the quality of reduction with the different fixation devices. Herbert and AO screw fixation was slower than the other implants ( p < 0.05). No difference in the time for reconstruction was observed with K-wires and FFS. Failure load was less for K-wires compared to FFS, Herbert screws and AO screws ( p < 0.05). With polycyclic loading, residual deformation was higher with K-wire reconstruction compared to FFS, Herbert screws and AO screws ( p < 0.05). Conclusion When using four different fixation devices, the fixation of standardised Bryan and Morrey type I fractures in the sawbone model differs when it comes to the time needed for reduction, but not in the quality of reduction. Stability was the same for the implants used, except for the K-wires. There is no argument in favour one of the screw implants over another in clinical use.