Medically reviewed by Dr. Tom Biernacki, DPM — Board-Certified Podiatric Surgeon — Balance Foot & Ankle, Howell & Bloomfield Hills, MI. Last updated April 2026.

What Is PTTD?

Posterior tibial tendon dysfunction (PTTD) is a progressive condition involving failure of the posterior tibial tendon — the primary dynamic support structure of the medial arch — leading to adult-acquired flatfoot deformity. It is the most common cause of progressive flatfoot deformity in adults and affects primarily middle-aged women, though it occurs across genders and ages. Left untreated, PTTD progresses from localized tendon pain to complete arch collapse and ultimately to arthritic destruction of the hindfoot and ankle joints.

At Balance Foot & Ankle in Howell and Bloomfield Township, Michigan, early diagnosis and stage-appropriate treatment of PTTD is a priority. The condition is highly treatable in its early stages but significantly more difficult to manage once deformity becomes rigid and arthritic.

The Role of the Posterior Tibial Tendon

The posterior tibial muscle and tendon originate in the deep posterior compartment of the lower leg, run behind the medial malleolus (the inner ankle bone), and insert primarily on the navicular bone and multiple other midfoot bones on the medial and plantar surfaces. This tendon serves two critical functions: it actively supinates the subtalar joint during the push-off phase of gait (locking the midfoot to create a rigid lever for propulsion), and it dynamically supports the medial longitudinal arch throughout the stance phase of walking.

When the posterior tibial tendon degenerates or tears, the arch gradually collapses, the heel tilts into valgus (outward), and the forefoot abducts (swings outward relative to the hindfoot). This is the classic adult-acquired flatfoot deformity associated with PTTD.

Stages of PTTD

PTTD is classified into four stages that guide treatment decisions:

• Stage I: Tendon inflammation and pain without deformity; the arch remains normal; single-leg heel rise is possible but painful
• Stage II: Tendon elongation or partial tear with flexible flatfoot deformity; the arch collapses with weight-bearing but can be passively corrected; single-leg heel rise is absent or very weak; the “too many toes sign” (seeing multiple toes beyond the heel from behind) is present
• Stage III: Rigid flatfoot deformity; the hindfoot valgus cannot be passively corrected; arthritis may begin in the subtalar and talonavicular joints
• Stage IV: Rigid flatfoot with valgus tilting of the ankle joint itself, indicating tibiotalar involvement

Risk Factors

PTTD risk factors include obesity, diabetes, hypertension, inflammatory arthritis, steroid use, prior medial ankle trauma, and pre-existing flatfoot. The tendon is susceptible to a zone of relative hypovascularity approximately 1–2cm distal to the medial malleolus — the most common site of initial tendon degeneration and tear.

Conservative Treatment for Stages I and II

Non-surgical treatment is effective for Stage I and many Stage II presentations when initiated early. The foundation is immobilization and support: an ankle-foot orthosis (AFO) or walking boot to rest the tendon while controlling flatfoot positioning, often combined with a short period of restricted weight-bearing. As inflammation resolves, transition to a University of California Biomechanics Laboratory (UCBL) orthosis or custom functional AFO that controls hindfoot valgus and supports the arch. Physical therapy strengthens the posterior tibial muscle and addresses calf flexibility. Weight loss reduces mechanical load on the tendon in obese patients.

Surgical Treatment

Surgical reconstruction is indicated when conservative treatment fails for Stage II disease or for Stage III-IV presentations. Stage II procedures typically combine posterior tibial tendon debridement or reconstruction (often with FDL tendon transfer), calcaneal osteotomy to realign the heel from valgus, and spring ligament repair. Stage III requires hindfoot arthrodesis (fusion) of the subtalar and talonavicular joints. Stage IV adds tibiotalar correction. Surgical complexity increases significantly with each stage, reinforcing the importance of early Stage I-II treatment to prevent disease progression.

If you have inner ankle pain and notice your arch collapsing or your foot flattening out, seek podiatric evaluation. Early PTTD is very treatable with conservative measures. Contact Balance Foot & Ankle at our Howell or Bloomfield Township office for evaluation.

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Posterior Tibial Tendon Dysfunction (PTTD) Guide

PTTD is the most common cause of adult-acquired flatfoot, progressively flattening the arch and causing inner ankle pain. At Balance Foot & Ankle, we catch PTTD early and provide stage-appropriate treatment — from custom orthotics and bracing to comprehensive surgical reconstruction when needed.

Learn About Our PTTD & Flatfoot Treatment → | Book Your Appointment | Call (810) 206-1402

Clinical References

1. Kohls-Gatzoulis J, et al. Tibialis posterior dysfunction: a common and treatable cause of adult acquired flatfoot. BMJ. 2004;329(7478):1328-1333.
2. Alvarez RG, et al. Stage I and II posterior tibial tendon dysfunction treated by a structured nonoperative management protocol. Foot Ankle Int. 2006;27(1):2-8.
3. Bluman EM, et al. Posterior tibial tendon rupture: a refined classification system. Foot Ankle Clin. 2007;12(2):233-249.

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Dr. Tom Biernacki, DPM is a double board-certified podiatrist and foot & ankle surgeon at Balance Foot & Ankle Specialists in Southeast Michigan. With over a decade of clinical experience, he specializes in heel pain, bunions, diabetic foot care, sports injuries, and minimally invasive surgery. Dr. Biernacki is a member of the APMA and ACFAS, and his patient education content on MichiganFootDoctors.com and YouTube has reached over one million views.