ConditionBones, joints & muscles
Posterior Tibial Tendon Dysfunction (PTTD)
Posterior tibial tendon dysfunction (PTTD) is a condition in which the tendon that supports the inner arch of the foot becomes inflamed, stretched or torn. As the tendon weakens, the arch gradually collapses, causing adult-acquired flatfoot. Symptoms start with pain and swelling along the inside of the ankle, followed by the foot rolling inward and the heel tilting out. It is most common in women over 40. Caught early, it usually improves with a boot, bracing and exercises; advanced cases may need surgery.
Also called: PTTD, adult-acquired flatfoot deformity, progressive collapsing foot deformity, posterior tibial tendon insufficiency, tibialis posterior dysfunction, posterior tibial tendinitis
At a glance
- What it is
- Weakening or tearing of the posterior tibial tendon, leading to a collapsing arch.
- Who gets it
- Most often women over 40; also people with obesity, diabetes, high blood pressure or flat feet.
- Symptoms
- Pain and swelling along the inside of the ankle and arch, worse with walking; arch flattening over time.
- Stages
- From tendon inflammation with a normal foot shape to a rigid flatfoot with ankle arthritis.
- Diagnosis
- Examination including the single-leg heel rise, plus X-rays and MRI or ultrasound.
- Treatment
- Rest in a boot, orthotics or braces, physical therapy; tendon and bone surgery for advanced cases.
When to get help
See a doctor within a day or two
- A sudden pop or tearing sensation on the inner ankle with immediate pain and inability to rise on tiptoe
- An ankle or foot that is red, hot and swollen, especially in someone with diabetes and reduced feeling (possible Charcot foot or infection)
- Severe ankle pain after a fall with inability to bear weight
Book a routine appointment
- Pain and swelling along the inside of the ankle that lasts more than 2 weeks
- An arch that is flattening, or a foot that is rolling inward compared with the other side
- Difficulty walking long distances, climbing stairs or standing on tiptoe on one foot
- Pain spreading to the outer side of the ankle in someone with a flat foot
Usually safe to manage at home
- Mild inner ankle soreness after a long walk that settles with rest and supportive shoes within a few days
What the posterior tibial tendon does
The posterior tibial muscle runs down the back of the lower leg. Its tendon wraps behind the inner ankle bone (medial malleolus) and attaches to bones on the underside of the midfoot. It is the main support of the arch and inverts the foot, allowing you to push off and rise onto your toes. When it fails, other ligaments become overloaded and the arch gradually collapses.
Causes and risk factors
- Overuse and degeneration with age, especially where blood supply to the tendon is poor
- Female sex and age over 40
- Obesity
- Pre-existing flat feet (flat feet)
- Diabetes and high blood pressure
- Steroid injections near the tendon
- Inflammatory arthritis, such as rheumatoid arthritis
- Injury, such as an ankle sprain or fall
- High-impact sports in younger people
Symptoms
- pain and swelling along the inside of the ankle and arch, often worse with activity (see ankle pain)
- tiredness or aching in the foot after standing or walking
- difficulty standing on tiptoe on the affected foot
- the arch gradually flattening and the foot turning outward
- the heel tilting outward when viewed from behind
- in later stages, pain on the outer side of the ankle as the heel bone presses against the fibula, and eventually osteoarthritis of the hindfoot and ankle
- difficulty with stairs, uneven ground and long walks
Stages
| Stage | Tendon | Foot shape | Typical treatment |
|---|---|---|---|
| I | Inflamed or degenerating, functioning | Normal | Rest, boot, orthotics, physical therapy |
| II | Stretched or torn, weak | Flexible flatfoot that can be corrected | Brace or orthotics; surgery if conservative care fails |
| III | Failed | Rigid flatfoot that cannot be corrected | Bracing or fusion surgery |
| IV | Failed | Rigid flatfoot with ankle tilting and arthritis | Bracing or ankle and hindfoot surgery |
Newer classifications call this "progressive collapsing foot deformity", but the principle is the same: earlier stages respond better to non-surgical care.
Diagnosis
A foot and ankle specialist will:
- look at both feet from behind while you stand; the "too many toes" sign shows more toes visible on the outside of the affected foot
- ask you to rise up onto your toes on one foot (single-leg heel rise): weakness or the heel not swinging inward suggests PTTD
- feel along the tendon for swelling and tenderness
- check whether the flatfoot is flexible or rigid
- examine the calf for tightness
Tests include weight-bearing X-rays to measure foot alignment and arthritis, and MRI or ultrasound to assess the tendon.
Treatment
Non-surgical (most early cases)
- Rest and immobilization: a walking boot or cast for 4 to 8 weeks to let the tendon calm down.
- Orthotics: custom or high-quality arch supports with a medial heel wedge.
- Ankle braces: lace-up braces or custom ankle-foot orthoses (such as an Arizona brace) for more advanced or non-surgical cases.
- Physical therapy: strengthening the posterior tibial muscle (including eccentric exercises), calf stretching (calf tightness adds strain) and balance work.
- Supportive shoes with a firm heel counter.
- Pain relief: ice and anti-inflammatory medicines at the label dose, if safe for you.
- Weight management.
Steroid injections are generally avoided because they can weaken the tendon further.
Surgery
Considered when pain and deformity continue despite 3 to 6 months of good non-surgical care:
- Tendon cleaning (debridement) for early disease.
- Tendon transfer: using a nearby toe flexor tendon to replace the damaged tendon, often combined with
- Calcaneal osteotomy: shifting the heel bone to realign the foot.
- Calf lengthening if tight.
- Fusion (arthrodesis) of hindfoot joints for rigid deformities or arthritis.
Recovery from reconstruction takes months, typically 6 to 10 weeks non-weight-bearing and up to a year for full recovery.
Outlook
Early-stage PTTD often settles with bracing and rehabilitation. Without treatment, it can progress to a rigid, painful flatfoot and arthritis. Surgery usually improves pain and alignment, although some stiffness may remain.
Frequently asked questions
What are the symptoms of posterior tibial tendon dysfunction?
Symptoms include pain and swelling along the inside of the ankle, aching after walking or standing, difficulty rising on tiptoe on one foot, and a gradually flattening arch with the foot rolling inward. Later, pain may move to the outer ankle.
Can posterior tibial tendon dysfunction heal on its own?
Mild, early PTTD can improve with rest, a walking boot, supportive shoes, orthotics and exercises. It rarely improves if the causes continue unchecked. Without treatment it often progresses, so early assessment is worthwhile.
What is the best treatment for PTTD?
Early stages respond best to a period in a walking boot, followed by orthotics or a brace, supportive shoes and a physical therapy program focused on strengthening and calf stretching. Surgery is reserved for persistent pain or progressive deformity.
Is PTTD the same as flat feet?
PTTD is one of the most common causes of flat feet developing in adulthood. Many people have flexible flat feet from childhood without any problem. PTTD causes a painful, progressive flattening of a foot that previously had a normal arch.
Sources
This guide was written from current patient and clinical guidance, including:
- American Academy of Orthopaedic Surgeons (OrthoInfo): Adult acquired flatfoot
- American College of Foot and Ankle Surgeons: Adult acquired flatfoot
- American Orthopaedic Foot and Ankle Society: Progressive collapsing foot deformity
- MedlinePlus: Flat feet
- NHS: Flat feet