- See:
Synthes Hybrid Fixator:
- Discussion and Initial Considerations:
- Operative Technique:
- may be combined w/
circular wire fixators;
-
reduction:
- in most cases, the fracture should be reduced prior to fixator application;
-
planning the configuration:
-
enhancement of fixator stability;
-
safe zones for pin insertion:
- plane of the fixator:
- consider the need for soft tissue coverage and position the fixator in way that
not to interfere with free flap coverage;
- because major bending moments on tibia during gait are in saggital plane, placment
of fixator pins and frame near the saggital plane improves stability;
- rigid quadrilateral frames w/ transfixation pins in coronal plane are somewhat
flexible in the saggital plane;
- use external fixator tube assembly to confirm the position of the proximal and distal pins;
- it is embarrassing to find out midway thru the case that the fixation bars
are not long enough to span the proximal and distal pins;
- 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;
-
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 thru both cortices;
- tented skin is released so no skin pressure is exerted near pin site;
-
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;
