- In MODERATE TO SEVERE cases a fourth procedure called a “posterior calcaneal osteotomy” is performed. This procedure is performed through a small incision on the outside of the foot just behind the outer anklebone. The heel bone is cut in an oblique fashion and slid to the inside of the foot. It is held in position by two screws. During the procedure the weightbearing portion of the heel bone is slid ¼” to almost ½” medially. Weightbearing is reestablished in a more correct position as the heel bone is centered underneath the tibia and the Achilles tendon has a more natural tendency to turn the heel bone under (supinate) rather than turn out (pronate). The heel bone is a well-vascularized bone that heals more quickly than the Achilles tendon, naviculocuneiform joint fusion or Cotton procedure. The screws that are placed in the back of the heel under the skin are left in permanently. We have found that when we are able to get the lower leg to be lined up perfectly straight with the heel bone we get a much better long-term outcome with a much less chance of recurrence of the deformity.
- Some surgeons favor another procedure called an “Evans calcaneal osteotomy”. It is a procedure that is performed on the outside of the back one-third of the foot. In this procedure it is theorized that the outside of the foot is shorter than the inside of the foot and opening the heel bone and placing bone graft in the area will equalize the inner and outer columns of the foot. When the procedure is carefully done, a bone graft from 6-10 mm is placed approximately 1 to 1.5 cm behind the calcaneal cuboid joint. The outer portion of the foot is “swiveled or swung inward” and this helps to reestablish an arch in three planes. Other procedures that are performed at the same time may include a lengthening of the Achilles tendon or gastroc. For severe deformities a double calcaneal osteotomy, which includes an Evans and a posterior calcaneal osteotomy can be performed. If during the procedure a “tripod” is not established, a naviculocuneiform fusion or a Cotton may be necessary to reestablish a normal plantar grade foot. While we perform the Evans procedure, we typically prefer others so that complications which are more common in an “Evans” are avoided. If necessary, an Evans procedure can always be performed at a later time.
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