Avascular necrosis of the talus is a difficult problem to manage, especially in the young and healthy. The only option, historically, has been a talectomy and hindfoot fusion. While this is a viable option, it is not without its morbidity. Arthritis of surrounding joints is common, occurring anywhere from 1-10 years after the procedure. This is especially true in younger patients, where loss of motion can be life altering both physically and mentally. The search for alternatives has been limited. Recently, 3D printing has become more ubiquitous and affordable and newer medical alternatives have arisen thanks to this technology. The 3D custom talus is relatively new in the orthopaedic community, but has been used at several centers with good success. It has been shown to re-establish the normal alignment of the foot, preserve motion (with some achieving almost physiologic motion), and allow for almost normal ambulation. However, the data is still limited and further study is necessary. Our facility was recently approved to perform this procedure. Our hypothesis is that custom 3D printed talar body replacements, either used alone or with total ankle replacements, will maintain physiologic motion, have no difference in complications when compared to hindfoot fusions with allograft, lead to good outcome scores and patient satisfaction scores. Patients diagnosed with avascular necrosis of the talus who have already decided to undergo a procedure involving a 3D custom talus as part of their standard care (talar replacement, total ankle/total talus, etc) will be enrolled in the study. Patients will follow standard post-operative protocols and return to clinic at designated time periods (2 weeks, 6 weeks, 3 months, 6 months, 1 year). X-ray evaluation, Range of motion, return to ambulation, walking speed and patient reported outcomes will be evaluated at each visit. Data will then be compared with baseline measurements and use to determine the progression of patients over time after the procedure

After patients have undergone a standard of care 3D talar augment procedure they will return to clinic at designated time periods (2 weeks, 6 weeks, 3 months, 6 months, 1 year). X-rays performed as standard of care will be evaluated. Walking speed will be assessed after patient is allowed to bear weight at the same designated time periods reported above. Patients will also answer questions regarding pain (VAS survey), satisfaction (SSQ-8 survey), outcomes utilizing AAOS foot and ankle scores (survey), and self-reported return to unassisted ambulation. Goniometer measurements will be taken in the clinic at all post-operative visits to determine ROM

Inclusion Criteria:

1. Subjects age 18 years or above at time of screening
2. Condition satisfies requirement for total talus replacement
3. Able to consent and participate in the study
4. No previous history of septic arthritis involving the hindfoot/midfoot
5. Previous ability to ambulate

Exclusion Criteria:

1. Active infection, sepsis, osteomyelitis or history of septic arthritis involving the hindfoot/midfoot
2. Unable to consent or participate in the study secondary to mental status
3. Condition does not qualify for a total talus replacement
4. Patients who are pregnant or imprisoned
5. Planned relocation or unable to return for required follow-up visits

Patients over 18 years of age diagnosed with avascular necrosis of the talar body and amenable to treatment with 3D custom augmentation

The Investigator will maintain all study records according to applicable University regulatory requirement(s). Hard copy records will be retained for at least 7 years after the last clinic follow-up visit at the Missouri Orthopaedic Institute in a locked filing cabinet. Electronic records will be retained for the same amount of time but on secured computers and servers. If the Investigator withdraws from the responsibility of keeping the study records, custody will be transferred to a person willing to accept the responsibility.