[Computer-assisted surgery (CAS)-guided correction arthrodesis of the ankle and subtalar joint with retrograde nail fixation].

OBJECTIVE

Restoration of a stable and plantigrade foot in deformities of the ankle and/or hindfoot and concomitant degenerative changes at the ankle and subtalar joint.

INDICATIONS

Deformities of the ankle and/or hindfoot and concomitant degenerative changes at the ankle and subtalar joint.

CONTRAINDICATIONS

Active local infection or relevant arterial insufficiency.

SURGICAL TECHNIQUE

Prone position and posterolateral approach to ankle and subtalar joint. Placement of dynamic reference bases (DRB) in the tibia and through a stab incision in the talus or calcaneus. Two-dimensional (2D) image acquisition for navigation. Definition of axes of the tibia, calcaneus, and hindfoot, and of extent of correction. Exposition of ankle and subtalar joint and removal of remaining cartilage. Computer-assisted surgery (CAS)-guided correction and transfixation of the corrected position with 2.5 mm K-wires. Three-dimensional (3D) image acquisition for analysis of the accuracy of the correction and planning of the drilling for the retrograde nail. CAS-guided drilling insertion of the nail. Insertion of locking screws in the calcaneus, talus and tibia. 3D image acquisition for analysis of the accuracy of the correction implant position.

POSTOPERATIVE MANAGEMENT

Partial weight bearing (15 kg) in an orthosis (Vacuped) for 6 weeks, followed by full weight bearing in a stable standard shoe.

RESULTS

From 1 September 2006 to 31 August 2008, 14 correction arthrodeses were performed. The accuracy was assessed by intraoperative 3D imaging. All achieved angles/translations were within a maximum deviation of 2°/mm when compared to the planned correction. Complications that were associated with CAS were not observed. In all 14 cases completing follow-up, timely fusion was registered.