Posterior tibial tendon dysfunction (PTTD) occurs when the tendon that supports your arch becomes inflamed, overstretched, or torn, leading to a gradual flattening of the foot, pain along the inner ankle, and — in more advanced cases — difficulty walking. Because the posterior tibial tendon is the primary structure holding up your arch, damage to it tends to progress slowly, which makes early recognition important.
Many patients describe the same pattern: mild inner-ankle soreness that comes and goes at first, then gradually worsens until the arch visibly starts to sag and the foot begins turning outward. The earlier PTTD is caught, the more treatment options remain nonsurgical. Below, our podiatrists explain what causes it, how we diagnose it, and the full range of treatments — from bracing to the newest regenerative options.
What is posterior tibial tendon dysfunction?
The posterior tibial tendon runs along the inside of the ankle and attaches to bones in the midfoot, where it works to support the arch and control the position of the foot with every step. When the tendon is repeatedly strained, it can become inflamed (tendinitis), stretch out, or partially tear. As the tendon weakens, it loses its ability to hold the arch in place, and the foot gradually flattens — a condition often called "adult acquired flatfoot."
What causes PTTD, and who is at risk?
PTTD typically develops from cumulative overuse rather than a single injury, though a significant ankle sprain can also damage the tendon. Common contributing factors include:
- Repetitive overuse from running, walking, or standing for long periods
- A history of ankle sprains or other ankle injuries
- Being overweight, which adds ongoing strain to the arch
- Diabetes and inflammatory conditions such as rheumatoid arthritis, which can weaken tendon tissue
- Naturally flat or low arches, which place extra demand on the tendon
- Age-related wear, as PTTD becomes more common with age
Because flat feet and PTTD are closely linked, patients with a flexible flat foot earlier in life are often at higher risk as they get older.
What are the symptoms of PTTD?
Symptoms usually appear gradually and worsen over time if untreated. Early signs include:
- Pain and swelling along the inside of the ankle, near the tendon
- A visibly flattening or collapsing arch
- The foot and heel rolling or turning outward
- Difficulty or inability to stand on your toes on the affected side
- Ankle instability that can contribute to secondary problems, including shin splints
- Pain that shifts from the inner ankle to the outer ankle as the arch collapses further
How is PTTD diagnosed?
Diagnosis starts with a physical exam, where your podiatrist checks for tenderness and swelling along the tendon, evaluates the shape of your arch, and watches your gait for signs of the foot rolling inward or outward. From there, imaging — typically MRI or ultrasound — helps confirm the diagnosis and shows how much damage the tendon has sustained, which guides the treatment plan.
How is posterior tibial tendon dysfunction treated?
Treatment depends heavily on how early the condition is caught. Most patients start with conservative care, and many respond well if treatment begins before the arch has collapsed significantly.
Conservative treatment
- Custom orthotics to support the arch and reduce strain on the tendon — see our custom orthotics options
- Ankle bracing to stabilize the foot and limit further stretching of the tendon
- Physical therapy targeting tendon strength and flexibility
- Activity modification to reduce repetitive loading while the tendon heals
- Anti-inflammatory medications to manage pain and swelling
Innovative and regenerative therapies
For patients whose tendon damage is more involved, newer regenerative options are increasingly used alongside traditional care. These include platelet-rich plasma (PRP) injections, stem cell therapies, and extracellular matrix products, all aimed at supporting the body's own healing response in and around the damaged tendon.
Surgery
Surgery is generally considered when several months of conservative treatment have not relieved symptoms, or when the tendon is severely torn. Depending on the extent of damage, surgical options range from debridement (removing damaged tissue) to tendon repair or tendon transfer, in which a nearby tendon is used to restore function.
Can PTTD be prevented?
You cannot eliminate every risk factor, but you can lower your chances of developing PTTD. Maintaining a healthy weight reduces ongoing strain on the tendon, and supportive, well-fitted footwear helps distribute load more evenly across the foot. If you have naturally flat feet or have had prior ankle sprains, custom orthotics and periodic check-ins with a podiatrist can help catch early tendon strain before it progresses.
Medically reviewed by the physicians at Wasatch Foot & Ankle Institute. Our board-certified, fellowship-trained podiatrists provide foot and ankle care in Farmington and South Ogden, Utah. This article is for general education and is not a substitute for an in-person evaluation.