Tibialis Posterior Dysfunction

The tibialis posterior tendon runs behind the bony prominence on the inner ankle and attaches into the arch of the foot. It is the main support for the arch, and it works hard with every step.

When the tendon becomes inflamed, stretched or torn, the arch gradually loses its support and begins to flatten. This is often called posterior tibial tendon dysfunction or PTTD, and also adult acquired flatfoot deformity. More recently the international consensus term has become progressive collapsing foot deformity, reflecting that the condition involves more than the tendon alone.

Who gets it?

It is more common in women, in people over 40, and in those who are overweight, have diabetes, high blood pressure or inflammatory arthritis. It can also follow an injury to the inner ankle. In many people it develops gradually with no single obvious cause.

Symptoms

The condition typically progresses through recognisable stages:

1. Pain along the inner ankle: Often the first symptom, following the line of the tendon behind the inner ankle bone. Worse with activity.

2. Swelling: Along the tendon on the inner side.

3. Arch flattening: The arch gradually lowers, often noticed as a change in foot shape or shoe fit.

4. Heel drifting outwards: Visible from behind. In more advanced cases the toes become visible from behind on the affected side — sometimes called the "too many toes" sign.

5. Difficulty on tiptoe: Rising onto the toes on the affected leg becomes difficult, then impossible.

6. Outer ankle pain: In later stages, as the heel drifts and the outer side of the ankle becomes compressed.

Pain often moves from the inner side to the outer side as the condition progresses, which patients sometimes interpret as improvement on the inner side rather than progression.

Why early assessment matters

While the deformity remains flexible, treatment options are broader and joint-preserving surgery is more likely to be possible. Once the foot becomes stiff and the joints arthritic, fusion is more often required.

This is one of the conditions where seeking assessment earlier genuinely changes what can be offered.

Treatment

Non-surgical treatment is the first approach and is effective for many people, particularly in the earlier stages:

• Custom orthotics to support the arch

• Bracing for more advanced cases

• Physiotherapy, with particular focus on strengthening the tendon

• Supportive footwear

• Activity modification

• Weight management where relevant

• Anti-inflammatory medication for symptom control

Where symptoms persist despite this, or where the deformity is progressing, surgery may be considered. This is planned individually and may involve tendon transfer, realignment of bone, lengthening a tight calf, and fusion of specific joints where they are already worn.

Dr Janan's approach

Dr Janan Chandrananth completed fellowship training in Bristol, a major United Kingdom foot and ankle centre, and in Tokyo under Professor Satoru Ozeki, past president of the Japanese Society for Surgery of the Foot, where reconstructive and joint-preserving techniques are a particular focus.

Assessment establishes which stage the condition has reached and whether the deformity is flexible or fixed, which is what determines the options available.