A Closer Look At The Distal Tibial Osteotomy For Ankle Varus
- Volume 25 - Issue 11 - November 2012
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Average AOFAS scores improved from 53.8 to 87 points and the Takakura score improved from 14.6 to 32.3 points.8 Pain levels also improved for this small subset of patients over their follow-up period. Researchers saw no significant difference in leg length discrepancy or the time to osseous healing between a medial closing and opening wedge osteotomy. There were two nonunions and one delayed union in this study.
Harstall and colleagues used a lateral closing wedge osteotomy in the treatment of nine patients with ankle varus.10 The average follow-up for this group was 56 months and the average time to osseous union was 10 weeks. The AOFAS and pain scales both significantly improved postoperatively to 74 and 30 respectively. Despite the angular correction, one patient required subsequent arthrodesis at 16 months postoperatively. Researchers found that anecdotally with a laterally based wedge, the incidence of hardware removal due to irritation was minimal and there was decreased leg length discrepancy and medial soft tissue contracture.
In a prospective study, Knupp and co-workers performed supramalleolar osteotomies on 94 ankles and followed them for 43 months.11 The aim of this study was to assess the progression of ankle arthritis and develop a classification algorithm using these findings. Preoperatively, researchers subdivided patients into categories based on the amount of ankle tilting (greater or less than 4 degrees) and the degree of joint space narrowing. Balancing procedures occurred as necessary to obtain a congruent joint. This happened for varus and valgus deformities of the ankle. The AOFAS scores for the varus and valgus ankles improved and total visual analogue scores improved as well. Of note, 10 ankles failed and went on to either total ankle replacement or arthrodesis. This low failure rate for supramalleolar osteotomies is similar to other studies.1,7,8
Distal tibial osteotomies can decrease the progression of ankle joint arthritis. They are powerful corrective procedures that require careful preoperative planning in all planes. Here are some further take-home pearls.
• Use long leg and foot full weightbearing films from the unaffected limb as normal comparisons.
• When performing a medial opening wedge osteotomy, maintain the lateral cortical hinge.
• Use a wide angle Hintermann distractor to obtain the correction under fluoroscopy for easy osteotomy access.
• We suggest the femoral neck allograft for its thick tricortical strut.
• Slightly overcorrect the deformity to allow for some settling.
Dr. McAlister is a current fellow at the Advanced Foot and Ankle Fellowship at the Orthopedic Foot and Ankle Center in Westerville, Ohio.
Dr. Philbin is a fellowship-trained foot and ankle surgeon who is currently in private practice in Westerville, Ohio.