Telescopic rod technique to reverse anterior subluxation of the talus during the correction of equinocavovarus deformity with the Ilizarov fixator

Abstract

Summary: Background/objective: Anterior subluxation of the talus (AST) can occur during the correction of equinocavovarus using Ilizarov external fixation, which should be reduced under anaesthesia and fixed by Ilizarov external fixation. The ankle joint has multi-directional dynamic rotational axis, so it is difficult to find the correct ankle rotational axis during external fixation, even for experienced doctors. The objective of this study is to describe a telescopic rod (T-rods) technique that allows AST to be reversed without anaesthesia during the correction of an equinovarus deformity with the Ilizarov external fixation. Methods: In patients with equinocavovarus foot deformity, corrective procedures including bone and soft tissue procedures were performed first, and then the Ilizarov fixator was applied. Correction of the deformity was started immediately after relief of pain and oedema in the foot and ankle. The Ilizarov apparatus was manipulated to apply gradual, controlled distraction as tolerated. If AST was found on the postoperative radiographs during correction by the Ilizarov apparatus, T-rods were installed immediately without anaesthesia to reverse AST. Results: Generally, after the T-rods were installed, the correction of AST is started. The anterior rod (A-rod) was shortened to cause ankle dorsiflexion. The T-rods were extended so that the talus would move backward slowly and return to the ankle joint, and the T-rods rotated forward at the same time. As a result, the talus was restored, and the equinocavovarus deformity was corrected. In the course of correction, the reduction of AST was confirmed by taking radiographs. Once AST was completely reduced, T-rods extension was stopped to prevent posterior subluxation of the talus due to excessive traction. Conclusion: Telescopic rods are effective for reversing AST during correction of equinovarus with an Ilizarov fixator. Moreover, telescopic rods may be used routinely for all patients to avoid AST. The translational potential of this article: AST can occur during the correction of equinocavovarus using Ilizarov external fixation. We describe a telescopic rod technique that allows AST to be reversed without anaesthesia during the correction of an equinovarus deformity with the Ilizarov fixator. This may guide surgeons to provide new perspectives and ideas in preventing AST and may support to design more targeted therapies to reduce AST.

Keywords

• Anterior subluxation of the talus
• Equinocavovarus
• Ilizarov
• Telescopic rod