Effect of supramalleolar osteotomy and total ankle replacement on talar position in the varus osteoarthritic ankle: a comparative study.

BACKGROUND: In varus osteoarthritic ankles, joint congruency is usually lost leading to progressive wear of the medial tibiotalar joint. Recent studies have shown that balancing the hindfoot with the aid of supramalleolar osteotomy (SMOT) is an effective method to decrease symptoms and to delay progression of osteoarthritis of the ankle joint. Resurfacing the articular surfaces with total ankle replacement (TAR), in contrast, may compensate for the lost joint congruency and lost stability of the talus at the peritalar joint. However, no literature exists with regard to the overall correction of talar position in all 3 planes when using these 2 treatment modalities. The purpose of this study was to determine the effect of SMOT and TAR on talar position in all 3 planes, and to compare the efficiency of both procedures in restoring overall hindfoot geometry.

METHODS: Out of 104 ankles with a varus-tilted ankle, 52 patients were treated with SMOT and 52 with TAR. Weight-bearing radiographs were analyzed to measure the talar position in all 3 planes, including the talar tilt angle (TT), the sagittal talocalcaneal inclination angle (TCI), and the talometatarsal 1 angle (TMT1) pre- and postoperatively.

RESULTS: Although after TAR the talar position was corrected in all the 3 planes, SMOT on the other hand did not fully correct the TT, and furthermore TMT1 remained unchanged.

CONCLUSIONS: Resurfacing of the worn-out articular surface and tensioning of ligaments, as is the case in TAR, radiographically restores the hindfoot geometry in the neutral position better than SMOT does.

LEVEL OF EVIDENCE: Level III, retrospective comparative study.