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AO/Weber: Type A Malleolar Fractures



- Discussion:
    - usually involves a supination-adduction injury;
    - frequently does well w/ closed reduction;
    - if frx in fibula is transverse, it is type I avulsion fibular frx;
    - since syndesmotic ligaments are intact, ankle mortise is also stable;
    - type A:  fibula fracture below syndesmosis (infrasyndesmotic)
              A1  isolated
              A2  w/ fracture of medial malleolus
              A3  w/ a posteromedial fracture

- Radiographs:

- Non Operative Treatment:
    - if avulsion frx of fibula is undisplaced or minimally displaced, & if there is no medial lesion (by exam & x-ray) then, apply a walking cast until fibula has healed (usually 6-8 weeks);
    - DVT prophylaxis for frx trauma


- Surgical Indications:
    - displaced, unstable, lateral malleolar avulsion frx w/ soft tissue disruption;
    - failure to close the gap may lead to non union;
    - displaced frx of medial joint complex, + vertical type medial malleolus fracture, w/ or w/o a frx of posteromedial aspect of the tibia;
    - osteochondral frx of medial articular surface of tibia or talus;

- Implants:
     - K wires, 1.6 mm & figure of 8 tension band wires, 1.2 for fibula;
     - for larger frag use one third tubular plate;
     - 4.0 mm cancellous bone screws, or 4.5 mm cannulated screws as lag screws for the medial malleolus;

- Operative Rx of Medial Malleolar Frx:
     - exposure of medial malleolus & careful reflexion of trapped periosteum;
     - reduction of any impaction of fracture of the articular surface of tibia and bone grafting of a resulting cancellous bone defect;
     - fixation of medial malleolus by tension band wiring (small transverse avulsion frag), or by 4.0 mm cancellous bone screws as lag screws (large shear fragment), or 4.5 mm cannulated screws;

- ORIF of lateral malleolus;
     - straight or hockey stick incision about 10 cm long is made anteriorly;
     - anatomical Reduction of Fibula and temporary reduction w/ pointed reduction forceps;
     - fixation of fibular frx by tension band wiring, or1/3 tubular plate

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