Patient Specific Talus Spacer Post Approval Study

Eligibility Criteria

• 1. Subject plans to undergo implantation of the Patient Specific Talus Spacer for avascular necrosis of the ankle joint independent of this research protocol;
• 2. Avascular necrosis of the ankle joint;
• 3. Age 21 years old or older;
• 4. Subject has good general health; and
• 5. Subject signs a written informed consent form (ICF) prior to the surgical procedure.
• 1. Presence of any contraindication identified in the device Instructions for Use;
• 2. Surgeon determines that the patient is not appropriate for the Talus Spacer procedure based on the device IFU (including the enumerated Warnings and Precautions);
• 3. Based on the medical opinion of the surgeon, the patient is not appropriate for the Talus Spacer procedure;
• 4. For female subjects, pregnancy;
• 5. Active systemic disease, such as AIDS, HIV, or active infection;
• 6. Active infection or the skin is compromised at the surgical site; and
• 7. Systemic disease that would affect the subject's welfare;
• 8. Is a prisoner, incarcerated, or has been coerced to participate in the study that could impact the validity of results;
• 9. Is currently participating in an investigational therapy (device and/or pharmaceutical) within 30 days prior to entering the study or such treatment is planned during the time course of follow-up.
• 10. If the Sponsor has notified the site that 30 subjects have been enrolled in the study with a Cobalt Chromium Patient Specific Talus Spacer, and the surgeon believes that a Cobalt Chromium Patient Specific Talus Spacer is the best option for the patient.
• 11. If the Sponsor has notified the site that 30 subjects have been enrolled in the study with a Titanium (Ti6Al4V) with Titanium Nitride (TiN) coating Patient Specific Talus Spacer, and the surgeon believes that a Titanium (Ti6Al4V) with Titanium Nitride (TiN) coating Patient Specific Talus Spacer is the best option for the patient.