Internal fixation of experimental intraarticular calcaneal fractures: a biomechanical analysis of two fixation methods

Abstract

Objective: To evaluate and compare the mechanical stability of two different fixation techniques on experimentally induced calcaneus fractures.

Methods: Thirteen fresh frozen cadaver lower limbs had intraarticular calcaneal fractures produced with an impact loading device. Internal fixation was then performed through lateral and medial approaches using 3.5-mm interfragmentary screws fixed to the posterior facet. Next, either a five-hole 1/3 tubular or five-hole reconstruction plate was placed on the lateral cortex. Radiographs were obtained to confirm reduction. The foot was then cyclically loaded for 500 cycles with a compressive load of 98 N, followed by loading to failure.

Results: The displacement at the posterior facet fracture line between the loaded and unloaded foot at the 500th cycle was 0.30 +/- 0.08 mm and 0.39 +/- 0.18 mm for the tubular and reconstruction plates, respectively. These displacements were not statistically significant (Student's t test p > 0.3). The load and displacement at failure for the tubular plate were 2021 +/- 1050 N and 6.10 +/- 1.75 mm, respectively. Those for the reconstruction plate were 1923 +/- 697 N and 4.57 +/- 1.32 mm (p > 0.09).

Conclusion: This study supports the mechanical viability of using less prominent plates for the fixation of intra-articular calcaneal fractures.