What one is the correct name? There is a lot of discussion going on as to what is the more appropriate name. There are merits for both name.
A lot of it depends on the nature of the primary pathology and if it is a primary concern of the posterior tibial tendon or is the main cause. https://podiatry-portal.com/adult-acquired-flatfoot-or-posterior-tibial-tendon-dysfunction-or-progressive-collapsing-foot-deformity/