Midfoot & Rearfoot

Flat Feet & Posterior Tibial Tendon Dysfunction

Adult-acquired flatfoot is a progressive condition driven by failure of the posterior tibial tendon. Caught early, it's very treatable. Caught late, it requires reconstruction.

Two Different Things

A flexible flatfoot present since childhood and a painless adult flatfoot are very different from adult-acquired flatfoot deformity - a progressive collapse of the arch caused by failure of the posterior tibial tendon (PTT). The latter is what we treat aggressively.

Stages of PTTD

  • Stage I: Painful, swollen tendon, normal arch.
  • Stage II: Flexible flatfoot deformity - the arch collapses with weight-bearing but reduces when offloaded.
  • Stage III: Rigid flatfoot deformity - the arch no longer reduces.
  • Stage IV: Deformity has progressed into the ankle joint.

Why Early Treatment Matters

Stage I and early Stage II disease often respond beautifully to immobilization, custom orthotics or AFO bracing, and a structured rehabilitation program - preserving the foot’s native architecture. Untreated, the deformity progresses, and reconstruction becomes more complex.

When Reconstruction Is Needed

For Stages II–IV that have failed conservative care, surgical reconstruction - combinations of tendon transfer, calcaneal osteotomy, midfoot fusion, and lateral column lengthening - restores alignment and function. Dr. O’Carroll individualizes the procedure to your stage and anatomy.

Get back on your feet!

Schedule a consultation with Dr. O'Carroll at our Pismo Beach or Santa Maria office. Dr. O'Carroll's schedule fills quickly - we recommend requesting an appointment as early as you can to get on the list.