Correction of coronal plane deformity maintained in TAR

In the short term, incongruent joints have greater loss of correction than congruent preoperative deformities.

Issue: November 2004

AOFAS Seattle [icon] A study of the short-term outcomes of patients undergoing total ankle replacement showed that the correction of coronal plane deformities is maintained at two years’ follow-up.

However, ankles with incongruent preoperative deformities have a greater loss of correction than ankles with congruent preoperative deformities over the first two years of follow-up, reported Andrew Haskell, MD, here at the American Orthopaedic Foot and Ankle Society 20th Annual Summer Meeting. Haskell worked with co-investigator Roger A. Mann, MD, on the study.

Deformity associated with failure

Since coronal plane malalignment after total ankle replacement may lead to premature failure, Haskell and Mann’s study sought to address whether patients with coronal plane malalignment of the ankle benefit from total ankle replacement.

Of 86 consecutive patients who underwent Scandinavian Total Ankle Replacement (STAR), Haskell and Mann identified 18 patients who had at least two-year follow-up with a preoperative coronal plane malalignment >10º.

Using a scatter plot of tibial vs. talar preoperative alignment, they were able to identify patients with congruent joints with varus or valgus malalignment, as well as patients with incongruent joints with varus or valgus malalignment.

Patients with talar and tibial alignment within 10º of each other were considered to have congruent joints. Patients with more than 10º difference between tibial and talar alignment were deemed to have incongruent joints.

The average age of patients was 62 years, and there were an equal number of men and women in the study.

“It should be noted that in intraoperative alignment, the goal was to place all components perpendicular to the plumb line of the body,” Haskell said. “Ligament balancing was performed as shown to help maintain the position of the talar component when it was felt that it was required.”

There were eight patients in the varus-congruent group, Haskell reported. “The tibial talar alignment was improved in the immediate postop period and the two-year follow-up. None of these patients developed progressive edgeloading,” defined as a consistent progression of at least 4º of change in talar component alignment over time, he said.

The valgus-congruent group was composed of one patient, and tibial-talar alignment was improved.

Six patients had varus-incongruent joints. “Talar alignment improved in immediate postop and two-year follow-up,” Haskell reported. “Four of these six patients developed edgeload.”

Three patients had valgus-incongruent joints. “Talar alignment improved in the immediate postop and two years,” Haskell said, with one patient developing edge-loading.

For more information:

Haskell A, Mann RA. Total ankle replacement in patients with a preoperative coronal plane deformity: Short-term results. Presented at the American Orthopaedic Foot and Ankle Society 20th Annual Summer Meeting. July 29-31, 2004. Seattle.