Synthes Uniplanar External Fixator for Tibial Frx



- 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 through 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;
    - 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



Original Text by Clifford R. Wheeless, III, MD.

Last updated by Data Trace Staff on Thursday, August 2, 2012 11:50 am