HC Chang Orthopaedic Surgery | Singapore

Adult Acquired Painful Flat Foot

Have you noticed that the medial arch of your foot is becoming flatter when you walk? You may be developing adult acquired flat foot.

This condition is typically caused by a problem with a tendon on the medial side of your foot called the Posterior Tibial Tendon that is not functioning well.

You may experience pain in the inner  side of your foot when you walk. The affected foot appears to roll outwards (the sole of the foot is trying to face outwards) when you walk. This is called over-pronation of the foot.

The back of your heel may start to point outwards (heel valgus).

Over time you may lose the ability to tip toe on that foot as the posterior tibial tendon stretches out and it may eventually tear.

Left Adult Flat Foot

What Is the Posterior Tibial Tendon?

The Posterior Tibial Tendon attaches the calf muscle to the bones on the inside of the foot and the main function of this tendon is to hold up the arch and support the foot when walking.

How Does The Posterior Tibial Tendon Gets Injured?

This tendon can be injured from:

1. Overuse.
2. Not wearing supportive shoes.
3. Foot sprain / trauma e.g.acute injury from a fall can tear the tendon or cause it to become inflamed.
4. Engaging in activities that involves the tendon: running, walking and climbing.

It is more common in women and in people older than 40 years of age. Additional risk factors include obesity, diabetes, and hypertension.

What Are the Signs and Symptoms of Posterior Tibial Tendon Dysfunction (PTTD)?

• Loss of arch height
• Swelling to medial ankle (along the course of the tendon)
• Inability to rise on the toes (single heel raise)
• Pain to medial ankle where the tendon lies during weight bearing. This may or may not be associated with swelling in the area.
• Lateral foot pain (sinus tarsi pain)
• Inward rolling of the ankle with outward rolling of the heel bone
•  Toes starting to point towards the outside
• Pain that is worse with activity. High-intensity or high-impact activities, such as running, can be very difficult. Some patients can have trouble walking or standing for a long time.

Collapse of Medial Arch

How To Treat?

PTTD is a progressive condition. Early treatment is needed to prevent relentless progression to a more advanced disease which can lead to more problems for that affected foot.

In general, the treatments include:
Rest

Reducing or even stopping activities that worsen the pain is the initial step.
Switching to low-impact exercise such as cycling, elliptical trainers, or swimming is helpful.
These activities do not put a large impact load on the foot.

Ice

Apply cold packs on the most painful area of the posterior tibial tendon frequenty to keep down the swelling.Placing ice over the tendon immediately after completing an exercise helps to decrease the inflammation around the tendon.
Nonsteroidal Anti-inflammatory Medication (NSAIDS)

Drugs, such as arcoxia, voltaren and celebrex help to reduce pain and inflammation. Taking such medications prior to an exercise activity helps to limit inflammation around the tendon. However, long term use of these drugs can be harmful to you with side effects including peptic ulcer disease and renal impairment or failure.
Casting

A short leg cast or walking boot may be used for 6 to 8 weeks in the acutely painful foot. This allows the tendon to rest and the swelling to go down. However, a cast causes the other muscles of the leg to atrophy (decrease in strength) and thus is only used if no other conservative treatment works.
Foot Insoles/Orthotics

Most people can be helped with orthotics and braces. An orthotic is a shoe insert. It is the most common non-surgical treatment for a flatfoot and it is very safe to use. A custom orthotic is required in patients who have moderate to severe changes in the shape of the foot. The custom orthotic is more costly, but it allows the doctor to better control the position the foot. Customised insoles are available at our clinic.
Physiotherapy

Physiotherapy helps to strengthen the injured tendon and it can help patients with mild to moderate disease of the posterior tibial tendon.

When Is Surgery Needed?

Surgery should only be done if the pain does not get better after a few months of conservative treatment.

The type of surgery depends on the stage of the PTTD disease. It it also dictated by where tendonitis is located and how much the tendon is damaged.

Surgical reconstruction can be extremely complex.

Some of the common surgeries include:

Tenosynovectomy – removing the inflamed tendon sheath around the PTT.

Tendon Transfer – to augment the function of the diseased posterior tibial tendon with a neightbouring tendon.

Calcaneo-osteotomy – sometimes the heel bone needs to be corrected to get a better heel bone alignment.

Fusion of the Joints – if osteoarthritis of the foot has set in, fusion of the joints may be necessary.

Case Illustration:

This is a 60 year old lady with painful right adult acquired flat foot.

She has collapse of the medial arch with heel pointing outwards (heel valgus). The posterior tibial tendon was stretched, painful but intact.

The deformity was still passively correctable.

I performed a tendon transfer – Flexor Digitorum Longus (FDL) transfer as well as a medial calcaneal osteotomy.

Exposure of the Posterior Tibial Tendon through a medial incision.

Note the tenosynovitis of the posterior tibial tendon sheath. This is a source of pain and should be excised.

The flexor digitorum longus tendon (FDL) is found and traced to down distally to be detached.

The FDL tendon is harvested and it will be used to augment the functions of the posterior tibial tendon to lift up the medial arch of the foot.

A bony tunnel is drilled into the navicular bone for the FDL tendon to be inserted into.

The FDL tendon is inserted into the bony tunnel.

The transferred tendon is secured with stitches.

An incision is made on the outer aspect of the heel to expose the heel bone for the medial displacement calcaneal osteotomy.

A saw is used to cut the heel bone into 2.

A medial displacement of the cut heel bone is performed. The idea is to correct the heel valgus into neutral so that the patient walks with the heel in neutral and not pointing outwards which will stress the PTT.

A guide wire is inserted into the calcaneum (heel) bone to prepare for a screw insertion.

The guidewire is inserted to stabilise the cut heel bone temporarily while a screw is being inserted for final fixation.

Fluoroscopy in the operating room shows correct placement of a single fixation screw into the heel bone.

The heel bone is being held by a single screw to allow healing of the osteotomy.

The operated foot is casted for 6 weeks.

Check x-rays in cast showing gradual healing of the osteotomy.

Appearance of the operated right foot after cast removal.

Note the correction of the right heel valgus into neutral.
This patient’s left foot pain resolved and she was able to walk without further pain.

For information on adult acquired flat feet and the associated problems and possible treatments, please contact

Dr HC Chang at 683 666 36 or 6694 1928 for an appointment.