Readers around Mount Prospect run into this condition under several names, which can make it sound like several different problems. The sources below show how the names connect.
Short answer: failure of the posterior tibial tendon
HSS defines it this way: "Posterior tibial tendon dysfunction (also called posterior tibial tendon insufficiency or adult acquired flatfoot ) literally means the failure of the posterior tibial tendon." So the first name is a literal description of the tendon problem.
One condition, more than one name
HSS lists posterior tibial tendon insufficiency and adult acquired flatfoot as alternate names. AAOS OrthoInfo titles its page on the same condition Progressive Collapsing Foot Deformity, so a second or third name does not have to mean a second or third diagnosis.
Where to read more
HSS has a full page on posterior tibial tendon dysfunction and an overview of common foot and ankle injuries and conditions. The AAOS OrthoInfo page on progressive collapsing foot deformity uses the newer name. Cleveland Clinic's page on tendinopathy treatment covers tendon problems more broadly.
What to ask next
- Which name does my clinician use for my condition, and do the other names mean the same thing?
- What is the plan for the tendon itself?
How the claim reads against the evidence
The name looks technical, but its meaning is plain: the posterior tibial tendon has failed to do its job. When a clinic offers a branded name for a foot problem, compare it with the names used by sources like these before assuming it is something new.