Comparing MagnetOs synthetic bone graft putty with a patient's own bone for hindfoot and ankle fusions

Inclusion:

1. Patient is able to read/be read, understand, and provide written informed consent and has signed the IRB approved informed consent.
2. Male or female patient ≥ 18 (considered skeletally mature) up to and including 75 years old
3. Patients requiring one of the following hindfoot fusion procedures, using surgical technique, necessitating rigid hardware fixation and supplemental bone graft/ substitute: ankle fusion (tibiotalar) subtalar fusion (talocalcaneal), calcaneocuboid fusion, talonavicular fusion, OR double fusion (any combination of any two of the following: subtalar, talonavicular and calcaneocuboid joints).
4. Hardware parameters - rigid fixation using screws, plates, staples, nails or a combination.

Exclusion:

1. Expected to need secondary intervention within one year following surgery.
2. Had prior fusion or attempted fusion of the joints to be fused.
3. Patient is not ambulatory.
4. Surgical technique where bone graft is not expected to be used.
5. Conditions at the surgeon's discretion in which general bone grafting is not advisable.
6. Radiographic evidence of fractures or pathologies around the fusion that could negatively impact the fusion process (e.g., growth plate fracture around the fusion or bone cysts).
7. Significant vascular impairment proximal to the graft site.
8. Acute and/or chronic infections in the operated area (soft tissue infections; bacterial bone diseases; osteomyelitis)
9. Pre-existing sensory impairment (e.g. diabetes, Charcot). Diabetics patients with HbA1c greater than 7.0 OR that were not sensitive to the 5.07 monofilament will be excluded.
10. Metabolic disorders know to adversely affect the skeleton (e.g., renal osteodystrophy or hypercalcemia).
11. If intraoperative soft tissue coverage is not planned or possible.
12. Receiving treatment with medication interfering with calcium metabolism (chronic use of glucocorticoid and use high dose NSAIDs 800 mg TID for \> the first 6 weeks post-op).
13. Has benign or malignant tumor at the surgical site.
14. Has history or presence of active malignancy (non-invasive skin cancer is allowed).
15. Has known substance abuse, psychiatric disorder, or a condition which, in the opinion of the investigator, may influence the healing or ability to comply with protocol requirements (e.g. prisoners, physically or mentally compromised, etc.).
16. Is involved in active litigation relating to his/her foot and ankle condition.
17. Participation in an investigational study within 30 days prior to surgery for study devices.
18. Patient with body mass index (BMI) \> 50.
19. Patient cannot comply with all post-operative evaluation and visits .
20. Any pre-existing condition that the surgeon determines could interfere with the patient's ability to perform objective functional measurements.
21. Women who are or intend to become pregnant within the next 12 months.