Arthrodesis (with/without correction) of the ankle and subtalar joint: A3 nail fixation with triple bending and mechanical navigation
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 joints.
Methods: Deformities at the ankle and/or hindfoot and concomitant degenerative changes at the ankle and subtalar joint. Failed (corrective) arthrodesis of the ankle and subtalar joints. Fused ankle and degeneration of the subtalar joint. Failed total ankle replacement with insufficient substance of talar body and/or degeneration of subtalar joint. Massive hindfoot instability. Methods: Active local infection or relevant vascular insufficiency, possible preservation of the ankle or subtalar joint (relative contraindication). Methods: Prone position and posterolateral approach to ankle and subtalar joints (alternative supine position/anterior approach; lateral position/lateral approach). Exposition of ankle and subtalar joints and removal of remaining cartilage. Optional corrective osteotomies and/or bone grafting. Correction and optional fixation of the corrected position with 2.0 mm K-wires. Mechanically navigated insertion of a retrograde guide wire in projection of the tibial axis and insertion of a second guide wire through the entry point of the nail lateral and dorsal to the tibial axis. Reaming and insertion of the A3 nail with a distal double bend; one posterior and one lateral, and a proximal bend corresponding to a slight recurvatum. Insertion of locking screws into the calcaneus, talus and tibia (twice with optional static or dynamic locking). Optional compression between calcaneus and talus, and between tibia and talus. Insertion of a drainage and layer-wise closure. Methods: For the first 6 weeks 15 kg partial weight bearing in an orthosis, followed by full weight bearing in a stable standard shoe.
Results: In October 2010 (n = 2) and from 15 October 2011 to 13 April 2012 (n = 26) 28 arthrodeses (with/without correction) with A3 fixation were performed. In all cases, exact nail placement was achieved. Thirteen cases completed follow-up (3-11 months) and showed timely fusion and full mobilization.