Pes Planus (Flatfoot) Clinical Presentation

Updated: Apr 28, 2021
  • Author: Gregory C Berlet, MD, FRCSC, FAOAO; Chief Editor: Vinod K Panchbhavi, MD, FACS, FAOA, FABOS, FAAOS  more...
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The clinical presentation of adult-acquired flatfoot deformity (AAFD) can be extremely variable, as can the progression and severity of the condition. Typically, the presentation directly correlates with the stage of the disease (see Staging). Common presenting symptoms include the following:

  • Visible pes planus (flatfoot) deformity (see the image below)
  • Inability or pain upon attempts to perform a single-leg heel rise
  • Pain along the course of the posterior tibial tendon (PTT)
  • Difficulty in walking
Photographs from patient with adult-acquired flatf Photographs from patient with adult-acquired flatfoot deformity (AAFD) show typical features of condition, demonstrated by abducted forefoot and valgus hindfoot.

The usual initial complaint of a patient with PTT dysfunction consists of pain and swelling in the medial ankle and midfoot during weightbearing. Over time, the patient may notice loss of the arch and the tendency to walk on the inner border of the foot. Loss of pushoff strength during gait occurs, and a limp may develop. As the patient's heel displaces into valgus and the forefoot abducts, pressure between the calcaneus and fibula may develop, causing painful impingement between the lateral ankle and calcaneus. Abnormal wear of the medial heel and inner border of footwear may also be noted.


Physical Examination

The patient is first examined while standing so as to facilitate comparison of the symptomatic foot with the asymptomatic foot. The arch heights of the two feet are assessed and compared. In later stages of PTT dysfunction, the arch is lowered and the forefoot abducted. Viewing the patient's foot from behind allows the examiner to evaluate forefoot abduction and heel valgus. The toes visible lateral to the heel are counted. Normally, one or two toes are visible lateral to the heel. In cases of significant forefoot abduction, three or more toes are visible. This "too-many-toes" sign is a test to confirm forefoot abduction (see the image below).

Pes planus (flatfoot). Too-many-toes sign. Three l Pes planus (flatfoot). Too-many-toes sign. Three lateral toes are visible on symptomatic left foot, compared with only two toes on right foot (black arrow). Medial midfoot is prominent and swollen (yellow arrow).

The angle that the heel forms with the longitudinal axis of the lower leg (the posterior tibiocalcaneal angle) also should be measured. This angle is increased in cases of significant heel valgus. The patient should then be asked to stand on one foot and rise up on the toes; he or she will usually need to hold on to the examining table or wall for balance during this maneuver. Normally, the heel inverts as the posterior tibial muscle contracts and as the gastrocnemius-soleus complex fires. In cases of PTT dysfunction, the heel does not invert, and the patient finds this single-limb heel-rise maneuver painful, difficult, or impossible (see the image below).

Pes planus (flatfoot). Single-limb heel-rise test. Pes planus (flatfoot). Single-limb heel-rise test. Patient with posterior tibial tendon (PTT) dysfunction is unable to rise up on toes because of inability to invert hindfoot.

The patient then is examined seated on the examining table, and the course of the PTT is palpated for tenderness. Swelling along the PTT sheath may be noted, and fluid may be palpated within the sheath. Posterior tibial strength is tested by holding the forefoot in a position of plantarflexion and eversion and asking the patient to invert the foot. During this maneuver, the PTT should be palpated to assess its continuity. The sinus tarsi and distal fibular area also should be palpated for tenderness because in later stages of PTT dysfunction, these areas of impingement may also be painful.

The knee is extended, the foot is held in a subtalar neutral position, and passive ankle dorsiflexion is measured. Usually, 10-20° of dorsiflexion is possible, but in cases of long-standing pes planus, dorsiflexion past neutral is often limited because of the development of a plantarflexion contracture. During the final stages of PTT dysfunction, the subtalar joint may be fixed in eversion, and inversion to neutral may be impossible.

Finally, forefoot flexibility is assessed by pronating and supinating the forefoot while holding the heel in neutral position. Although the subtalar joint may be flexible, the transverse tarsal joint may have become fixed in varus, preventing plantigrade positioning of the forefoot (see the image below). This finding has important implications for surgical treatment.

Pes planus (flatfoot). Fixed forefoot varus is cha Pes planus (flatfoot). Fixed forefoot varus is characterized by elevation of medial side of forefoot, even after heel is placed in neutral position.