- w/ the distal radius in a reduced position, percutaneous K wires are inserted, and then the distraction is released and the wrist is taken out of flexion;
- in the study by Dunning CE et al, the authors investigated the changes in fracture stability when using supplemental radial styloid pinning in combination with external fixation;
- 8 previously frozen cadaveric upper extremities were mounted in a computer-controlled wrist-loading apparatus;
- this device was used to generate finger and forearm motions through loading relevant tendons.
- unstable extra-articular distal radius fracture was simulated by removing a dorsal wedge from the distal radius metaphysis;
- electromagnetic tracking system measured fragment motion following randomized application of a Hoffman external fixator, a Hoffman external fixator with 2 supplemental radial styloid pins, and a dorsal 3.5-mm AO plate;
- addition of radial styloid pins to a construct stabilized by an external fixator significantly improved fragment stability, approaching that achieved with the dorsal AO plate;
- Supplemental pinning improves the stability of external fixation in distal radius fractures during simulated finger and forearm motion
- in the report by Wolfe SW, et al, the authors simulated unstable extra-articular distal radius fractures were created in 7 fresh-frozen cadaveric upper extremities and stabilized using 4 different external fixators;
- physiologic muscle tension across the wrist was simulated by application of 40-N load distributed among the wrist tendons;
- fracture stability was reassessed for each of the constructs after augmentation of the fracture fragments with a single dorsal transfixion K-wire;
- K-wire augmentation demonstrated a significant reduction in motion of the distal radial fragment of at least 40% in all 3 rotational planes;
- for flexion/extension, the reduction in motion was from 4.5° to 2.6°.
- for radial/ulnar deviation, the range of motion decreased from 3.0° to 1.5°.
- rotational motion declined from an average of 3.2° to 1.2°.
- addition of the single dorsal transfixion K-wire significantly improved stability of each of the 4 fixators in at least 1 of the 3 planes in which motion was measured;
- data supported concept of K-wire augmentation for increasing stability of an unstable extra-articular DRF regardless of the type of Ex Fix that is used
- A biomechanical comparison of different wrist external fixators with and without K-wire augmentation
- references:
- Intraarticular fractures of the distal radius: a cadaveric study to determine if ligamentotaxis restores radiopalmar tilt.