Ankle arthrodesis using internal screw fixation.

Ankle arthrodesis treated by external fixation frequently results in complications from pin tract infections, loss of position, nonunion, and malunion. A method of ankle arthrodesis using 6.5-mm cancellous screws as the primary fixation hardware was developed. The most important screw is placed from the posterior malleolus into the neck and head of the talus, and medial and lateral malleolar screws are added to secure fixation. Near-normal anatomy is maintained with this technique because little or no bone, only cartilage, is removed. Earlier cases were all done through an anterior approach. Later, special techniques were developed for placing screws and strain-relieving bone grafting was added to promote union. Twenty-three cases that were treated by the earlier technique are reviewed. The overall fusion rate was 74%. Three conditions (avascular talus, pyarthrosis, and spasticity) were identified that placed patients at high risk for failure of fusion. Of the patients who were not in a high-risk group, only one had a delayed union. When the high-risk patients were not included in the statistics, the fusion rate was 93%. The evolved technique shows great promise for accurate and trouble-free ankle arthrodesis.