[Comparative biomechanical study of 3 types of osteosynthesis of the Duparc grade IV fractures of the calcaneus: value of triangular internal fixation].
OBJECTIVE
We present an in vitro biomechanical study performed to evaluate and compare, for an experimentally produced fracture of the calcaneum (Duparc grade IV), the reaction of 3 standard models of internal fixation commonly used in these fractures and which occupy different volumes.


METHODS
We compared different methods of fixation using fresh human calcanei. In two experimental series, we compared triangular internal fixation (3 1/4 tube AO plates Saragaglia), Y internal fixation (2 1/3 tube AO plates Bezes), isolated screw technique (three 3.5 diameter screws, two 4.5 diameter screws). The plates and screws were made of identical material (316L). Both series used 8 pairs of bone (talo-calcaneum system) with the same fracture submitted to a 200N to 1000N load. Stiffness and movement were analyzed using 8 references on the calcaneum.


RESULTS
The stiffness and movement analysis with 8 references points demonstrated the superior resistance to bending with the triangular internal fixation. Fixation stability was significantly better than with the Y or screw technique.


CONCLUSIONS
This study underlined the importance of triangular trabecular organization of cancellous bone on calcaneum biomechanics. We showed that the 3 (anterior, posterior and inferior) trabeculae must be repaired in calcaneum fractures to achieve horizontal and vertical stability of the talar joint.


CONCLUSIONS
In our hands, restoration of the triangular architecture of calcaneum fractures, to resemble a roof truss, where the talus is fixed to the triangle vertex, is fundamental to obtain a rigid and stable internal fixation.
Badet
R
R
Service de Chirurgie Orthopédique et Traumatologie du Sport, C.H.U. de Grenoble, Hôpital Sud.
Ribeiro
F
F
Rumelhart
C
C
Tourne
Y
Y
Badulescu
A
A
Saragaglia
D
D
D001696:Biomechanical Phenomena; D002102:Cadaver; D002111:Calcaneus / Q000293:injuries*; D005593:Fracture Fixation, Internal / Q000379:methods*; D050723:Fractures, Bone / Q000601:surgery*; D006801:Humans
Etude biomécanique comparée de 3 ostéosynthèses des fractures enfoncements du calcaneum stade IV de Duparc. Intérêt du montage en triangulation.