Posterior Tibial Tendinitis

What the posterior tibial tendon does

The tibialis posterior muscle runs down the back of the calf. Its tendon curves behind the medial malleolus (the bony bump on the inner ankle) and attaches to bones in the middle of the foot. It:

• supports the inner arch
• turns the foot inward
• locks the foot into a rigid lever so you can push off when walking

When it fails, the arch collapses, the heel tilts outward and the forefoot points outward.

Symptoms

• pain and swelling along the inside of the ankle and arch
• pain that worsens with standing, walking, running or climbing stairs
• tenderness along the tendon
• difficulty or pain rising onto tiptoe on the affected foot
• the arch flattening over time
• in later stages, pain on the outside of the ankle as the heel shifts and bones press together
• "too many toes" visible from behind on the affected side

Stages

Causes and risk factors

• overuse from high-impact activity or sudden increases in walking or running
• existing flat feet
• age over 40, especially women
• obesity
• diabetes and high blood pressure, which affect tendon health
• inflammatory arthritis such as rheumatoid arthritis
• steroid injections near the tendon
• ankle injury

Diagnosis

A clinician watches you stand and walk, checks the arch and heel position, and tests:

• single-leg heel raise: inability or pain suggests tendon dysfunction
• "too many toes" sign: seeing more outer toes from behind on the affected side
• tendon tenderness and strength against resistance

Imaging:

• X-rays while standing to assess arch collapse and arthritis
• ultrasound or MRI to show tendon degeneration, tears and inflammation

Conditions such as tarsal tunnel syndrome, stress fractures and arthritis are considered.

Treatment

Early (stage 1 and flexible stage 2)

• rest from aggravating activity and switch to low-impact exercise (cycling, swimming)
• immobilization in a walking boot for 2 to 6 weeks for acute pain
• ice and NSAIDs at the label dose for pain; avoid NSAIDs with kidney disease or stomach ulcers
• custom orthotics with arch support and a medial heel wedge
• ankle braces (such as an ankle-foot orthosis or lace-up brace) for more support
• supportive shoes with a firm heel counter
• physical therapy: progressive strengthening of the tibialis posterior, calf stretching and balance work
• weight management

Steroid injections into the tendon are generally avoided because they can weaken it.

Surgery

Considered when symptoms persist after 3 to 6 months of non-surgical treatment or deformity progresses:

• tendon debridement or repair for early stages
• tendon transfer (often using the flexor digitorum longus) combined with bone realignment osteotomies for flexible flatfoot
• joint fusion (triple arthrodesis) for rigid deformity

Recovery from reconstruction usually takes 6 to 12 months.

Outlook

Early-stage tendinitis often improves well with rest, orthotics and exercises. Without treatment, it can progress to a painful, rigid flatfoot. Early recognition is key.

Frequently asked questions

What are the symptoms of posterior tibial tendinitis?

The main symptoms are pain and swelling on the inside of the ankle and along the arch, worse when walking, standing or running, and difficulty rising on tiptoe. Over time, the arch may flatten.

How long does posterior tibial tendinitis take to heal?

Mild cases may improve in 6 to 12 weeks with rest, a boot, orthotics and physical therapy. More advanced cases can take several months, and some need surgery.

Can posterior tibial tendon dysfunction cause flat feet?

Yes. When the tendon weakens or stretches, it can no longer support the arch, leading to adult-acquired flatfoot, also called progressive collapsing foot deformity.

What shoes are best for posterior tibial tendinitis?

Supportive shoes with a firm heel counter, good arch support and a stable sole, combined with custom orthotics, help reduce stress on the tendon. Avoid flat, flexible shoes and high heels.