CME OnDemand: 2022 AOFAS Annual Meeting-Foot and Ankle Offset (FAO) Does Not Reflect the Actual Hindfoot Alignment in Cases Involving Ankle and/or Sagittal Foot and Ankle Deformities

Foot and Ankle Offset (FAO) Does Not Reflect the Actual Hindfoot Alignment in Cases Involving Ankle and/or Sagittal Foot and Ankle Deformities

Back to course

Video Transcription

Video Summary

In this video presentation, Shuyang Li discusses the limitations of using foot and ankle offset (FAO) to assess three-dimensional height-foot alignment on weight-balance CT scans. FAO was developed as a biometric tool in 2017 and has gained popularity for height-foot alignment assessment. However, the authors of this study have observed that FAO has a high false negative rate and fails to reflect certain deformities and information about the ankle and tibia. The study aims to demonstrate the inadequacy of FAO through case examples and mathematical algorithms. Part one of the study analyzes 31 cases and compares the FAO values with clinical and radiographic diagnoses, showing that the FAO values do not align with the actual deformities. Part two of the study involves manipulating a normal foot using weight-bearing CT scans and calculating FAO values to provide geometric evidence and algorithmic explanations. The study concludes that FAO is not an accurate tool for assessing height-foot alignment or ankle alignment.

Asset Subtitle

Shuyuan Li, MD, PhD, Sera Sempson, BS, Wanjun Gu, BS, BA, Chao Wang, BS, Mingjie Zhu, DAOM, MPH, Ming-Zhu Zhang, MD, PhD, Kenneth J. Hunt, MD, and Mark S. Myerson, MD

Keywords

foot and ankle offset

three-dimensional height-foot alignment

weight-balance CT scans

limitations of FAO

inadequacy of FAO