**5. Conclusions**

As a conclusion, we can say that an MCO is a good option to perform in patients suffering with AAFD developed mainly due to a failure of the spring ligament. Nevertheless, if patients exhibit plantar fascia weakness and/or tibialis posterior tendon dysfunction, this technique could also be applied, but carefully. In this case, we found that an MCO causes an important increase in the lateral metatarsals (a possible reason for pain in the long term) and around the osteotomized area. These factors create a risk of calcaneal fracture.

**Author Contributions:** Conceptualization, J.B. and R.L.-G.; methodology, C.C.-D.l.P. and J.B.; software, B.D.S. and C.C.-D.l.P.; validation, C.C.-D.l.P. and R.L.-G.; formal analysis, B.D.S. and J.B.; investigation, C.C.-D.l.P. and J.B.; resources, B.D.S. and C.C.-D.l.P.; data curation, R.L.-G.; writing—original draft preparation, C.C.-D.l.P. and J.B.; writing—review and editing, J.B. and R.L.-G.; visualization, B.D.S.; supervision, C.C.-D.l.P.; project administration, J.B.; funding acquisition, J.B. All authors have read and agreed to the published version of the manuscript.

**Funding:** This research was funded by the Ministry of Economy and competitiveness of the Government of Spain through the project DPI2019-108009RB-100.

**Data Availability Statement:** All the data and results are included within the manuscript.

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