Locked plate fixation of the comminuted distal fibula: a biomechanical study

Abstract

RESEARCH • RECHERCHELocked plate fixation of the comminuted distal fibula: a biomechanical study Background: The purpose of this study was to compare the biomechanical properties of locked versus nonlocked lateral fibular bridge plating of comminuted, unstable ankle fractures in a mode of catastrophic failure. Methods:We created comminuted Weber C fractures in 8 paired limbs from fresh cadavers. Fractures were plated with either standard or locked one-third tubular bridge plating techniques. Specimens were biomechanically evaluated by external rotation to failure while subjected to a compressive load approximating body weight. We measured the angle to failure, torque to failure, energy to failure and construct stiffness. Results:There was no significant difference in construct stiffness or other biomechanical properties between locked and standard one-third tubular plating techniques. Conclusion:We found no difference in biomechanical properties between locked and standard bridge plating of a comminuted Weber C fibular fracture in a model of catastrophic failure. It is likely that augmentation of fixation with K-wires or transtibial screws provides a construct superior to locked bridge plating alone. Further biomechanical and clinical analysis is required to improve understanding of the role of locked plating in ankle fractures and in osteoporotic bone.Contexte : Cette étude avait pour but de comparer les propriétés biomécaniques d'une plaque péronière latérale verrouillée ou non verrouillée dans des fractures de chevilles comminutives instables, en présence d'une défaillance catastrophique. Méthodes :Nous avons infligé des fractures comminutives de Weber de type C à 8 paires de membres de cadavres frais. Les fractures ont été corrigées au moyen de plaques tubulaires d'un tiers standard ou fixes. Les spécimens ont été évalués au plan biomécanique par rotation externe jusqu'à défaillance, tout en étant soumis à une charge compressive correspondant environ au poids corporel. Nous avons mesuré l'angle, le moment de torsion et l'énergie au point de défaillance et la rigidité de la structure.Résultats : Nous n'avons noté aucune différence significative sur le plan de la rigidité de la structure ou des autres propriétés biomécaniques entre les plaques tubulaires d'un tiers fixes et standard. Conclusion :Nous n'avons trouvé aucune différence sur le plan des propriétés biomécaniques entre les plaques standard et fixes sur des fractures péronières comminutives de Weber de type C dans un modèle de défaillance catastrophique. Il est probable qu'une fixation accrue au moyen de broches en K ou de vis transtibiales procure une meilleure structure que les plaques fixes seulement. Il faudra effectuer d'autres analyses biomécaniques et cliniques pour mieux comprendre le rôle des plaques fixes dans les fractures de la cheville et dans l'os ostéoporotique.

A biomechanical comparison study of a modern fibular nail and distal fibular locking plate in AO/OTA 44C2 ankle fractures

“…Multiple biomechanical studies have been performed on AO/OTA 44C-type fractures in regard to syndesmotic stability with an intact fibula [ 29 – 34 ]. There is limited literature regarding the creation and biomechanical testing of an AO/OTA 44C-type fracture with a comminuted fibula [ 35 ]. Most biomechanical models of comminuted fractures are in more distal, AO/OTA 44B-type fractures [ 35 – 37 ].…”

“…There is limited literature regarding the creation and biomechanical testing of an AO/OTA 44C-type fracture with a comminuted fibula [ 35 ]. Most biomechanical models of comminuted fractures are in more distal, AO/OTA 44B-type fractures [ 35 – 37 ]. Thus, in order to simulate the typical AO/OTA 44C2 fibular fracture, we marked the location of a fibular osteotomy at 7 and 8 cm proximal to the distal fibula tip and made transverse osteotomies at marked sites with an oscillating saw, removing an approximately 1-cm fibula cross section.…”

Double Plating of Distal Fibula Fractures

“…1,3 However, other studies have shown no biomechanical difference between the two. 17,18 In fact, Minihane et al 19 reported inferior biomechanical properties with lateral locked plating when compared with posterolateral antiglide plate fixation. The position of the posterolateral antiglide plate allowed for longer, bicortical screws through the distal fragment, improving fixation.…”

Fixation of Distal Fibula Fractures

“…15,18 Conversely, those in favor of unicortical screw placement point to the possibility of intra-articular screw placement with the use of bicortical screws. 38,40 The use of an interfragmentary lag screw ( Figure 1) has been employed for increased compression and stability in oblique fibular fractures. 19,20 Lag screw only fixation of the long oblique fracture of the lateral malleolus has also been used and has demonstrated equivalency to plate fixation in young patients with good bone stock.…”