A Prospective, Randomized, Single-blind, Controlled, Multi-center Study to Assess the Safety and Performance of MagnetOsTM Compared to Autogenous Bone Graft in Patients Undergoing Hindfoot or Ankle Fusions.

In this study, following a screening period of a maximum of 45 days, approximately 126 patients will receive either MagnetOs Putty/Easypack Putty or autograft in conjunction with rigid hardware (arthrodesis) to treat hindfoot and ankle disorders. They will be randomized (1:1) into one of two treatment groups: standard rigid fixation with MagnetOs Putty/Easypack Putty or local autograft from the calcaneus, distal tibia, or proximal tibia.

They will be followed up at discharge at weeks 2, 6, 12, 24 and 52 post-surgery. The primary endpoint will be analyzed at 24 weeks post-op using CT-scan, and patients will continue follow-up for safety and efficacy for one year post operatively.

In this study, MagnetOs will be applied according to the IFU (Putty) approved in the US, Europe, Middle- East and Australia and Easypack Putty (approved in the US).

The surgical procedures studied in this clinical trial will include rigid hardware fixation and supplemental bone graft/substitute in the following procedures: 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. These procedures will be left to the investigator's discretion.

Radiographs images will be taken at screening, weeks 6, 12, 24 and 52; CT-scans will be taken at weeks 24 and 52 post-op If the patient has a secondary surgical intervention (procedure that adjusts or in any way modifies or removes part of the original implant configuration) at any time after the 6 month visit, the next CT scan will not be necessary. Starting at week 12, all XR images will be weight bearing.

Inclusion:

• Patient is able to read/be read, understand, and provide written informed consent and has signed the IRB approved informed consent.
• Male or female patient ≥ 18 (considered skeletally mature) up to and including 75 years old
• 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).
• Hardware parameters - rigid fixation using screws, plates, staples, nails or a combination.

Exclusion:

• Expected to need secondary intervention within one year following surgery.
• Had prior fusion or attempted fusion of the joints to be fused.
• Patient is not ambulatory.
• Surgical technique where bone graft is not expected to be used.
• Conditions at the surgeon's discretion in which general bone grafting is not advisable.
• 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).
• Significant vascular impairment proximal to the graft site.
• Acute and/or chronic infections in the operated area (soft tissue infections; bacterial bone diseases; osteomyelitis)
• 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.
• Metabolic disorders know to adversely affect the skeleton (e.g., renal osteodystrophy or hypercalcemia).
• If intraoperative soft tissue coverage is not planned or possible.
• 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).
• Has benign or malignant tumor at the surgical site.
• Has history or presence of active malignancy (non-invasive skin cancer is allowed).
• 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.).
• Is involved in active litigation relating to his/her foot and ankle condition.
• Participation in an investigational study within 30 days prior to surgery for study devices.
• Patient with body mass index (BMI) > 50.
• Patient cannot comply with all post-operative evaluation and visits .
• Any pre-existing condition that the surgeon determines could interfere with the patient's ability to perform objective functional measurements.
• Women who are or intend to become pregnant within the next 12 months.