Contribution of minimally invasive bone augmentation to primary stabilization of the osteosynthesis of Schatzker type II tibial plateau fractures: Balloon vs bone tamp.

BACKGROUND: Schatzker type II tibial plateau fractures necessitate the least invasive treatment possible. Arthroscopic reduction by bone tamp followed by osteosynthesis is the current gold standard for this type of tibial plateau fracture. The objective of this study was to compare this technique to anterior approach tuberoplasty with balloon reduction. The comparison criteria were residual articular step off, metaphyseal cavity volume formed during reduction, and mechanical strength to separation and to depression displacement.

METHODS: Fractures were created on 12 human cadaveric tibiae and reduced by a minimally invasive approach in six specimens by a balloon, and by bone tamp in the six others. Articular step off and metaphyseal-epiphyseal cavity volume were measured by TDM. Mechanical tests were performed up to assembly failure to characterize structural strength. Secondary displacements, fracture depression displacement and separation were measured by optical methods.

FINDINGS: There was no significant difference in step off measurement after balloon reduction or bone tamp (0.29 cm vs 0.37 cm; p = 0.06). The cavity volume formed by balloon reduction was significantly smaller than the volume created by bone tamp reduction (0.45 cm3 vs 5.12 cm; p = 0.002). The compressive load required for assembly failure was significantly greater in the balloon group than in the bone tamp group (1210.17 N vs 624.50 N; p = 0.015).

INTERPRETATION: There exists a correlation between load to failure of the assembly frame and the metaphyseal volume required for bone fracture reduction. The minimally invasive balloon technique has fewer negative effects on the osseous stock, thereby enabling better primary structural strength of the fracture.