- PTTD is wear and inflammation of the tendon that supports your arch — when it weakens, the arch progressively collapses.
- It usually starts with pain and swelling on the inside of the ankle and a flattening arch you can see in the mirror.
- Stage I and II respond to bracing, custom orthotics, and physical therapy. Stage III and IV often need reconstructive surgery.
- Patients who ignore early signs frequently end up needing a fusion or a more complex reconstruction that could have been avoided.
- PTTD is often misdiagnosed as "just plantar fasciitis" — if your arch is visibly changing or pain is on the inside of the ankle, get a real evaluation.
What is posterior tibial tendon dysfunction?
The posterior tibial tendon runs from the calf, behind the inside ankle bone, and attaches to the bones of the arch. It is the single most important supporter of the arch — every time you push off, it tightens and lifts the arch into a stable platform. When the tendon becomes inflamed (tendonitis) or starts to tear, it loses that supporting function, and the arch begins to collapse over weeks, months, or years.
PTTD is staged I to IV based on how far that collapse has progressed. Stage I is pure tendonitis, stage II is a flexible flatfoot deformity, stage III is a rigid deformity, and stage IV adds ankle joint involvement. Treatment depends entirely on stage. Catching PTTD in stage I or II is the difference between a brace and a fusion.
At NES, we evaluate every adult patient with new inside-ankle pain or a visibly changing arch for PTTD specifically. The conservative protocol — supportive boot or brace for several weeks, custom orthotics, structured physical therapy — works well for the majority of stage I and II cases. Surgical patients are co-managed across podiatry and orthopedics depending on the reconstruction needed.
See it in motion
Animations licensed from ViewMedica · Swarm Interactive
The posterior tibial tendon originates from the deep posterior calf muscles, runs behind the medial malleolus (inside ankle bone), and inserts onto the navicular bone and several other bones of the medial arch. Its primary job is to invert the foot and elevate the arch during push-off. As the tendon fails, the spring ligament and other arch-stabilizing structures also begin to fail, accelerating the collapse.
What it feels like
PTTD has a recognizable evolution. Symptoms in order of progression:
- Pain and swelling on the inside of the ankle, just below the inside ankle bone
- Difficulty standing on tiptoe on one foot (the "single-heel-rise" test)
- A visibly flattening arch — comparing one foot to the other in the mirror
- The heel rotating outward when viewed from behind ("too many toes" sign)
- Pain that moves to the outside of the ankle as the deformity progresses (bone-on-bone impingement)
- Aching after standing, walking, or working a shift on your feet
- Difficulty walking on uneven ground
Why it develops
PTTD typically develops in adults over 40, with several known contributing factors:
- Female sex and age over 40 — the most common demographic
- A pre-existing flexible flatfoot that puts chronic load on the tendon
- Obesity, which increases the daily mechanical load on the arch
- Diabetes, hypertension, and inflammatory arthritis (e.g., RA)
- Repetitive impact from running, basketball, or high-volume walking
- Previous ankle injury that overstretched the tendon or supporting ligaments
How we diagnose posterior tibial tendon dysfunction
PTTD is diagnosed clinically — the single-heel-rise test, observation of arch flattening, and the "too many toes" sign from behind are usually enough for a confident diagnosis. We confirm with weight-bearing X-rays to stage the deformity. MRI is reserved for cases where surgery is being planned, to evaluate the tendon's integrity and the spring ligament. Catching PTTD early — before stage III — keeps the most successful treatment options on the table.
Non-surgical care
Conservative care is the right answer for stage I and II PTTD. Our typical protocol:
- A short course (4–6 weeks) in a walking boot or ankle-foot orthosis (AFO) brace to rest the tendon
- Custom orthotics designed with significant arch support and a medial heel post
- Physical therapy focused on calf flexibility, posterior tibial strengthening, and balance work
- Activity modification — reducing high-impact activity until the tendon recovers
- Anti-inflammatory medication for the inflamed tendon, when appropriate
- Weight management for patients where excess load is a contributing factor
- Long-term, daily orthotic use to keep the arch supported and prevent progression
Surgical care
Surgery is considered for stage II patients who fail conservative care, and for all stage III and IV patients. The goal is to restore the arch, balance the foot, and prevent further progression. We co-manage these cases with orthopedics depending on the reconstruction required.
- Flexor digitorum longus (FDL) tendon transfer to replace the failed posterior tibial tendon
- Medial calcaneal sliding osteotomy to realign the heel under the leg
- Lateral column lengthening (Evans osteotomy) to restore the arch height
- Spring ligament reconstruction when the soft-tissue supports of the arch have failed
- Triple arthrodesis (fusion) for rigid stage III deformities
PTTD reconstruction recovery is significant — typically non-weight-bearing in a cast for 6–8 weeks, transitioning to a walking boot for another 4–6 weeks, then to supportive shoes and physical therapy. Return to full activity is usually 6–9 months.
When to see a specialist
- Inside-ankle pain that has lasted more than 2–3 weeks
- A visibly changing arch — one foot looks flatter than the other
- Difficulty doing a single-leg heel raise (cannot rise onto your toes on the affected foot alone)
- Pain that's moved from the inside to the outside of the ankle (suggests stage III progression)
- Any new flatfoot deformity in an adult — this is rarely "just aging"
PTTD is treated by every NES podiatrist, with Dr. Mia Horvath and Dr. Yama Dehqanzada handling the more complex reconstructive cases. Dr. Ron Bowman (MD orthopedics) co-manages stage III–IV patients who require fusion. Stage I and II patients are routinely seen at any of our 8 Portland-area clinics.