Adult acquired flatfoot deformity (AAFD) has been addressed with an algorithmic approach based on classifications that have attempted to isolate this complex deformity into stages. Classifications allow orthopedic surgeons to discuss a pathologic entity in an academic setting; however, rigid classification systems are not able to accurately describe the nuances of a complex process and guide treatment in all cases. This statement was made by Miller1 in 1927: “There can be no dogmatic classification of flatfoot.” Although he was discussing the care of pediatric flatfoot, the concept of avoiding dogmatic treatment of this multifactorial disorder is applicable to all conditions. This difficulty is acutely noted when discussing posterior tibial tendon (PTT) dysfunction because medial column instability does not play a prominent role in the traditional classification schemes; however, it is a significant contributor to the pathologic process.