- See:
Weber A Fractures: Lateral Malleolus
- Discussion:
- results from
supination-adduction fracture (
Weber A)
- adduction forces result in a vertical fracture of the
medial malleolus
at the junction of the plafond and malleolus;
- transverse fibular frx or tear of lat collat occurs concomitantly;
- medial soft tissues are intact so that interpostion is not problem;
- main problem is comminution at medial corner of
Mortise;
- plafond may be comminuted w/ impacted fragments, leading to varus tilt
of mortise & post traumatic arthritis;
- Surgical Technique:
- vertical frx of medial malleolus are fixed w/ cancellous screws
placed perpendicular to the fracture site;
- usually 2 cancellous screws are required;
- washers may be needed because of thinner medial cortex;
- when choosing site of screw insertion, avoid areas likely to produce further
comminution of the fragment;
- screws should be seated in dense bone of the central distal tibial metaphysis
and thus should be approximately 40 mm long;
- do not attempt to anchor them in the far cortex, which is too thin to provide
much purchase;
- Comminution:
- medial surface should be inspected for articular crush of tibial surface or
talar dome;
- w/ joint congruity, impacted fragments need to be reduced w/ bone graft applied
to metaphyseal defects;
- if proximal portion of vertical frx is comminuted, butress plate may be required;
- w/o use of butress plate a varus deformity of talus may develope;
- plate may be small
DC plate,
one third, a T or clover leaf plate will suffice;
------------------------------------------
Vertical Shear Fractures of the Medial Malleolus: a biomechanical study of five internal
fixation techniques.
Roolan BC, Koval KJ, Kummer FJ, Sanders R, Zuckerman JD.
Foot Ankle 15: 483-489, 1994.
