Thinner tuberosity osteotomy is more resistant to axial load in medial open-wedge distal tuberosity proximal tibial osteotomy: A biomechanical study.

BACKGROUND

The purpose of this study was to investigate axial load resistance of the tibia depending on the thickness of tibial tuberosity osteotomy in medial open-wedge distal tuberosity proximal tibial osteotomy (OWDTO). The hypothesis is that a thin tibial tuberosity osteotomy shows high axial load resistance of the tibia.

METHODS

The OWDTO model was constructed from imitation bones of the tibia. Distal tibial tuberosity osteotomy was performed with thicknesses of 7, 14, and 21 mm (n = 5 for each group). Cyclic axial-load fatigue tests were performed to investigate the strain at five measurement points on the OWDTO model. An axial-load failure test was also performed to investigate the maximum strain for failure.

RESULTS

The 7-mm OWDTO model showed a significantly lower stain range than the 14-mm model at the middle part of the lateral hinge (P = 0.0263, mean difference: -852.6 με), posterior part (P = 0.0465, mean difference: -1040.0 με), posterior tibial cortex (P < 0.0001, mean difference: -583.4 με), and plate (P = 0.0029, mean difference: -121.6 με). There were no significant differences in the strain at the tibial tuberosity between the groups. The axial load for complete failure was significantly higher in the 7-mm model than in the 21-mm model (P = 0.0010, mean difference: 2577.0 N). The failure points were at the lateral hinges.

CONCLUSIONS

Thinner distal tibial tuberosity osteotomy is more resistant to axial load and may be recommended for the prevention of tibial and lateral hinge fractures after OWDTO.