The effect of plate design and fixation type on primary stability after open wedge high tibial osteotomy

Background: The stability of the open wedge high tibial osteotomy is dependent on an undamaged cortical hinge and design of the plate. Aims: We evaluated the primary stability of two internal fixation devices for open wedge high tibial osteotomy. Methods: Five pairs of cadaveric tibia with 10? valgus correction were stabilized with a newly designed plate with hybrid fixation and 10 mm spacer block and with conventional T plate with 10 mm spacer block. Static axial loads were applied until ultimate failure of the construct. Results: The average load at initial failure of the new plate construct was 4757.7 N compared to 3022.43 N obtained with the T plate, (p<0.01). The difference in initial stiffness of both constructs was not significant (p=0.27). The mean ultimate load at failure of the new plate construct was 5280.6 N compared to 3635.3N obtained with the T plate, (p=0.001). Conclusion: The new plate with hybrid fixation, provides substantial load resistance but similar stiffness when compared to standard T plate.