Gelenk-Klinik

Adult Acquired Flatfoot Deformity (AAFD)

In what follows we provide you with information about adult acquired flatfoot deformity (AAFD) and the methods used at our clinic to treat the condition. Years of general orthopedic experience and specialization in foot care allow us to arrive at clear diagnoses and provide effective, stage-specific treatment.

What is adult acquired flatfoot deformity?

The normal foot is constructed in a way that enhances our capacity to stand and walk. The essential form of the foot is given by a longitudinal arch and a transverse arch.
The term adult acquired flatfoot deformity refers to the following deformities or departures from the standard form of the foot.

When viewed from the front, the heel of the foot appears to tilt downward toward the medial (big toe) side of the foot.
When viewed from lateral side, the longitudinal arch appears to sink towards the stepping surface of the foot.

When viewed from above, the middle of the foot and the forefoot appear to turn towards the lateral (small toe) side of the foot.

What follows is a description of acquired flatfoot deformity, which occurs primarily in adults.

How is the longitudinal arch stabilized?

The tarsal bones are held together by ligaments and a stirrup-like sling that begins in the muscles of the calf and extends downward in the form of tendons that fork around the ankle before continuing down to the underside of the foot.

The posterior tibial tendon is the tendon the runs down from the calf along the inside of the ankle to the underside of the foot where it attaches to the navicular bone on the medial (big toe) side of the foot. The peroneal longus tendon is the tendon that runs down from the calf along the outside of the ankle to the underside of the foot where it attaches to the first metatarsal bone on the lateral (little toe) side of the foot, effectively completing form of the stirrup. The spring ligament complex also works together with the posterior tibial tendon and the plantar fascia to stabilize the longitudinal arch.

How is adult acquired flatfoot deformity to be explained?

Adult acquired flatfoot deformity often arises in connection with a damaged and dysfunctional posterior tibial tendon. This is why the condition used to be referred to as posterior tibial tendon dysfunction (PTTD). The posterior tibial tendon, the part of the stirrup that supports the longitudinal arch, slackens while the peroneal longus muscle that attaches on the lateral side of the foot continues to function, unopposed. As a result, the longitudinal arch collapses and the middle of the foot and the forefoot are pulled in the direction of the little toe by the action of the peroneal longus muscle.



What are the known causes of adult acquired flatfoot deformity?

Rheumatism-related inflammation in the sheath of the posterior tibial tendon can weaken and impair the function of the posterior tibial muscle. The exposed position of the tendon behind the medial ankle as well as accident-related injuries may contribute to the disorder.

In addition to inflammation in the sheath of the tendon, posterior tibial muscle dysfunction may also be caused by inflammation in the tendon itself (tendonitis), tendon tears and tendon ruptures. These factors lead to a slackening of the muscle and a partial or complete loss of its function as well as a corresponding collapse of the longitudinal arch.

Who is affected by adult acquired flatfoot deformity?

The condition primarily affects women above the age of 50. Indeed, the incidence of AAFD in women is 3 times greater than in men. The cause of this distribution is not known. AAFD is also seen more frequently in individuals suffering from diabetes and high blood, as well as in individuals who have used steroids for prolonged periods.

What are the symptoms of AAFD?

Our patients often complain of pain when loading the inside of the foot just below the inner ankle. In some patients, this pain extends from the medial or inner edge of the foot upwards around the ankle to the lower leg.

Patients frequently complain only of swelling, either on the inside or outside of the ankle.

Depending on the stage of the condition, patients may also notice the deformity and its progress over the last several months.

Other patients complain only of pain on the lateral edge of the foot just in front of the outer ankle when bearing weight.

In addition to pain in specific locations, many women complain only of not being able to walk as far as usual and of a slight fatigue or weakness in the foot.

The increasing deformity is often reflected in the pattern of wear one sees in the shoes of the patients. The interior edge of the shoes tends to show signs of disproportionate wear. The bed of the shoe may also fail as a result of the improper weight distribution.

How is AAFD diagnosed and evaluated?

AAFD can be reliably diagnosed by an experienced physician on the basis of a careful physical examination and weight-bearing x-rays (x-rays taken with the patient standing up).

The deformity may have developed very gradually or within a relatively short period.

The examination allows the physician to determine the exact nature and extent of the deformity as well as the presence of swelling, pain when pressure is applied to the tendon or to the sinus tarsi. The patient will also be asked to perform simple tests, including the too many toes sign and the single heel-rise test, to help the physician arrive at an ever more precise diagnosis.

Your doctor will also examine other parts of your foot, the range of motion in the joints of your foot, the stability of the relevant ligaments and the strength of the relevant muscles as a means of ruling out other disorders.

It is important to examine the degree to which the deformity can be corrected as a basis for arriving at a treatment decision.

The weight-bearing x-rays will be evaluated and the metatarsal-talar angle will be measured as a means of quantifying the deformity.

A physical examination by a specialist and x-ray examinations are indispensable when it comes to making a treatment decision.

We would be happy to assist you if you have any questions.

What forms of treatment are available for AAFD?

Conservative forms of treatment are advisable for most cases of AAFD.

Cortisone injections are generally ruled out because they can lead to a further weakening of the structures that support the longitudinal arch. In contrast, a shoe insert or a special orthotic device is almost always advisable.

The purpose of shoe inserts and orthotic devices is to provide support for the longitudinal arch. Such inserts must include a prominent arch and must be placed in appropriately stable shoes. The success inserts for AAFD depends on the nature of the inserts themselves and the quality of the shoes in which they are placed.

Further measures:

• Physical therapy, including ultrasound treatment and cryotherapy

• Physical therapy aimed to strengthen the muscle only if appropriate

• Augmentation of shoes with slight arches

All special shoes and inserts are monitored at our clinic and optimized in close cooperation with a shoemaker whenever appropriate.

If conservative treatment is not sufficient, it will be necessary to consider the surgical options for AAFD.