- See:
- Foot Inclusion:
- Safe Zone of Pin Insertion:
- Debridment:
- aggressive & repeated debridments of all devitalized tissue, including large fragments of bone;
- consider debridment of bone ends with a hall burr inorder to promote bony opposition and compression;
- Reduction:
- fracture should be reduced as much as possible prior to application of ex fix;
- Soft Tissues:
- see soft tissue coverage for the leg
- soft tissue lacerations should be opposed prior to application of the fixator in that the wound is not gaped open by the half pins;
- Choice of Hardware:
- EBI Fixator
- Synthes (see below);
- Planning Ex Fix Configuration:
- Dynamization:
- alawys consider the need for postoperative dynamization, hence plan the configuration to allow for shortening;
- Comminuted Fractures: (or Oblique Frx)
- if frx is comminuted or oblique fracture fragments will not transmit axial load;
- these frx require stacked frame for enhanced stability;
- Diaphyeal Fractures:
- appropriate length is fitted with 4 pin holding clamps;
- place most proximal & distal holding clamps as far apart as possible
- proximal pin is placed, preferably at junction of diaphysis and metaphysis, to gain purchase in the thick cortical bone;
- place inner holding clamps approx 2 cm from frx site;
- Proximal Frx:
- generally, the first bone screw is inserted into shorter fragment;
- if a cancellous site is chosen, the hole is drilled only with the 3.5 mm drill, and a 5.0 mm Schanz screw is used;
- small proximal tibal fragment can be stabilized w/ external fixator
using cluster of 2-3 transfixation pins from lateral to medial;
- Distal Frx:
- generally, the first bone screw is inserted into shorter fragment;
- need to avoid muscle impalement:
- avoid impaling anterior tibial or toe extensor tendons;
- w/ external fixators about the ankle, there is greater incidence of drainage from transfixtion that passed thru middle of anterior compartment than from half pins placed through medial tibia which underlies rather stationary subQ tissues;
- Plane of the Fixator:
- consider the need for soft tissue coverage and place the fixator in way not to interfere with free flap coverage;
- Frx'ed Fibula:
- plating of the fibula via a separate incision may increase overall rigidity while avoiding problems of lag screw fixation into open tibial wounds;
- once healed, intact fibula can also facilitate later posterolateral bone grafting of tibia if union is delayed;
- Incision:
- Schanz Screw and Insertion Pins:
- all pins are placed thru stab wounds
- 10 mm incision is made at chosen site using soft tissue guide;
- if cancellous site is chosen, hole is drilled only with the 3.5 mm drill, and a 5.0 mm Schanz screw is used;
- Drilling Technique:
- all half pins are predrilled using fresh, sharp drills
- predrilling reduces bone temperature by approximately 50%;
- hand drilling or low speed drilling is preferred;
- all drilling and pin application is done thru sleeve trochar units to prevent winding and necrosis of subcutaneous tissues;
- 3.2 mm drill is used for 5 mm half pin (Synthes System)
- drill through both cortices;
- tented skin is released so no skin pressure is exerted near pin site;
- Reduction (for Synthes Fixator):
- provisionally align frx, & use external fixator tube assembly to confirm the position of the distal pin;
- first pin is inserted into proximal fragment close to the joint;
- second pin is inserted into distal frag in same plane, close to distal joint;
- placing this in cortical bone may provide better purchase, but sometimes dense cancellous bone of tibial pilon must be used;
- fixator tube is assembled to both proximal and distal half pins;
- frx is reduced & connecting devices are tightened;
- Final Fixation
- w/ triple drill guide placed thru inner clamps, & inner two 5.0 mm cortical half pins are inserted at least 1 cm proximal or distal to frx site;
- ensure that pins are well away from areas of comminution;
- clamps are placed close to skin for frame strength, but at least one inch away to permit wound access;