Posterior tibial tendon dysfunction (PTTD), a leading cause of adult-acquired flatfoot deformity, involves progressive tendon degeneration and medial arch collapse. MR imaging remains the diagnostic cornerstone, combining high-resolution morphologic sequences with the potential for quantitative mapping techniques that may permit better detection of early microstructural tendon changes. Dynamic and ultrahigh-field (7T) protocols may further enhance biomechanical assessment and guide personalized surgical planning. Concurrently, innovations in tendon augmentation, fiber tape reinforcement, and 3 dimensional-bioprinted grafts offer more tailored reconstructive options. Finally, MR imaging-based postoperative monitoring of graft integration and repair integrity help to optimize long-term outcomes in PTTD.