Which joints are fused in a triple arthrodesis?
The subtalar, calcaneocuboid, and talonavicular joints. Both RA and JIA affect the subtalar and transtarsal joints. These joint involvements can be isolated or combined, and there has been a trend toward isolated arthrodesis of involved joints rather than triple arthrodesis when possible. Particularly common is isolated talonavicular joint destruction. If this presents in an adult with RA, then isolated fusion is recommended. Conversely, if the involvement occurs at a young age secondary to JIA, then the entire transtarsal joint (talonavicular, calcaneocuboid) should be arthrodesed because this will provide a longer-term satisfactory result.
Isolated subtalar arthrodesis is commonly performed when the remaining articulations of the triple joint are uninvolved and supple. Triple arthrodesis requires similar precision in positioning as does ankle arthrodesis to maximize walking biomechanics. In general, insensate feet (usually secondary to diabetes) are a contraindication to bony fusion as a result of the high likelihood of skin ulceration and subsequent infection.