The Ankle Spacer-a hemiarthroplasty for treatment of severe osteochondral defects of the talus.

OBJECTIVE: The Ankle Spacer system has been developed as a joint-preserving option for patients with failed treatment of large talar osteochondral defects (OCDs). It is a one-piece implant system that replaces the articulating upper talus surface of the tibiotalar joint. INDICATIONS: Large OCDs with failed prior surgical intervention(s) and/or multiple talar OCDs on the talar surface, posttraumatic or degenerative osteoarthritis, or avascular necrosis of the talus. CONTRAINDICATIONS: Severe malalignment exceeding 7° and other ankle deformities that would not allow proper rasping of the talus, obesity, blood supply limitations, severe osteopenia, and previous or active infections. SURGICAL TECHNIQUE: The surgery is carried out via a central approach to the ankle joint. The tibiotalar joint was distracted to remove the cartilage on the upper talar surface with special talus rasps and to perform microfracture of the entire talar surface. The appropriate Ankle Spacer trial was then inserted into the joint and fluoroscopy was used to check for proper trial size and positioning. After thorough cleaning of the prepared bone bed, the Ankle Spacer was inserted with a special seating instrument. POSTOPERATIVE MANAGEMENT: One surgeon in our center implanted ten Ankle Spacers between April 2018 and October 2019. The first short-term data with follow-up of 3 months were collated. RESULTS: No implant-related complications were recorded. American Orthopaedic Foot and Ankle Society (AOFAS) score increased from 55.5 to 79.5 points, European Foot and Ankle Society (EFAS) score increased from 5.6 to 13.5 points, and pain score decreased from 3 to 1.1 points. None of the patients' radiographs showed signs of loosening or osteoarthritis progression.