Compression Arthrodesis

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- Charnley Method:
- compression arthrodesis as accomplished by Charnley shows little
      consideration of biomechanical principles;
- he used one talar pin & one tibial pin w/ compression between them;
- pin is placed anterior in the talus so posterior pull of the Achilles tendon will
      keep the arthrodesis compressed;
- this provides stability in only one plane;
- this system to be relatively stable only in anteroposterior shear and
      dorsiflexion-plantarflexion modes, & to be unstable w/ any rotation;
- Charnley method requires that Achilles tendon to help fixation with his device;
- Calandruccio Compression Device (Richards):
- provides three-point fixation w/ stability in all planes of movement
      by its triangular configuration;
- Surgical Technique:
- longitudinal incision either in the midline or medial and lateral;
- all articular cartilage and subchondral bone must be removed;
- talus is relatively avascular, and bleeding cancellous bone w/
      tourniquet in place cannot often be found;
- shortening of extremity occurs with more bone resection;
- fibular osteotomy seems inherent to any attempt at fusion;