**4. Conclusions**

Images taken at six weeks post-op showed no evidence of device failure. The implant failed mechanically as well as clinically. Failure in the device construct caused lack of union. The first follow-up X-ray images showing evidence of device failure via screw fracture were taken at 18 months post-op. The average time for tibiotalocalcaneal arthrodesis fusion is about 19 weeks. Since imaging evidence supports device failure initiating between six weeks and 18 months, it cannot be said with certainty that the device maintained its integrity for the amount of time necessary for fusion. The revision surgery implemented a pediatric distal femoral osteotomy plate. There is no follow-up data on the revision. The following are a few reasons that may be considered for the overall failure of the PHILOS plate:


**Acknowledgments:** Gerard Simon, Air Force Research Laboratory, Dayton, Ohio provided access to the characterization facilities. Dinesh Gundapaneni assisted with sample preparation, microstructure and hardness testing of the material.

**Author Contributions:** Madhurima Vallentyne did the initial work as a part of her independent research, Jason Ina continued the further characterization work. Michael Boin reviewed the patient charts and provided clinical insights. Kathleen Shugart performed the SEM analysis and texture related research. Farah Hamandi performed mechanical tests, theoretical aspects of the paper and in the revisions. Richard Laughlin performed the revision surgery and removed the device components. Tarun Goswami, led this research study, recruited students, medical students and residents, verified the analytical methods and edited or written the body of the paper.

**Conflicts of Interest:** The authors declare no conflict of interest.
