Sliding external fixator "a product design and cadaveric experiment"

External fixation spanning a joint like the elbow, while maintaining joint mobility, is a well-established practice, and it could be done with a variety of external fixation systems. In current systems, correct identification of the elbow center of rotation under X-ray guidance with lateral views is mandatory. If the center of rotation of the fixator is not aligned with that of the elbow joint, the assembly will not work. This new design idea aims to propagate the principle of sliding external fixation applied on the extensor side of a joint, with the limbs of the fixator being able to slide in and out during joint extension and flexion, respectively, without hindering the joint movement, without the need to use X-ray guidance to identify the center of rotation.

A cadaveric experiment was carried on using a sliding fixator prototype applies on two cadaveric elbow specimens, which were tested though the arc of movement.

Assembling the fixator over the intact elbows without identifying the center of rotation did not impede the joint movement. Furthermore, after surgical dislocation of the elbow, the external fixator was able to keep the joint congruent, throughout the movement arc.

It was possible to apply a sliding external fixator on the extensor surface of a joint without identifying the center of rotation, and that does not seem to impede the joint movement, while can still keep the dislocated joint congruent despite attempted distraction.