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When buttress plates are placed on comminuted fractures as shown here they should be placed “across the comminution” not “across from the comminution.”

When placed “across from” comminution buttress plates are asked to do something they cannot really do. The far side of the bone will not hold its own length and the plate cannot, as the screws simply “toggle” in the plate allowing the opposites side of the bone to collapse. “Fixed angle” plates such as blade plates, compression hip screws and condylar screws are designed to prevent toggling in order to prevent this phenomenon.

External Fixators: Nowadays fixators are most often indicated to apply tension (resist compression) to fractures of the metaphysis or epiphysis. Metaphyseal fractures treated in this fashion include Colles fractures and proximal tibial metaphyseal fractures. Epiphyseal fractures include intraarticular fractures of the distal radius, bicondylar fractures of the tibial plateau treated with thin wire fixators and plafond fractures. These cancellous bone fractures are difficult to treat with IM nails as there isn’t enough bone for the nail to bite in, and difficult to treat with plates as the comminuted bone doesn’t hold well. However, they heal quickly, before fixator pins loosen and must be removed. In the past the most common indication for external fixation was the open diaphyseal fracture. Unfortunately, healing takes so long in the diaphysis that fixator pins generally loosen before healing is complete. Unreamed IM nails generally have the same infection rate as external fixators and mechanically are stronger, and so they usually will last long enough for those fractures to heal.

This is an example of a metaphyseal fracture treated with a fixator. When the epiphyseal block of bone is intact, it is generally better to place your pins in the epiphysis, rather than bridging (and thus immobilizing) a joint which could othrewise be mobilized. This also works well in the proximal tibia. When the epiphysis is broken many surgeons use “thin wire” fixators to avoid “bridging the joint”.

This is an example of a “joint bridging” ex fix where an epiphyseal (intraarticular) fracture of the distal radius is reduced by “ligamentotaxis” wherein the capsular ligaments pull the fragments back into fairly good alignment.  


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