Acquired flatfoot is defined as an abnormal flatness of the sole and the medial longitudinal arch of the foot. This condition is also referred to as pes planovalgus or pes planus.

The condition may be caused by posterior tibial tendon dysfunction; arthrosis of the joints in the foot, which may be due to a previous fracture of the or dislocation; changes in the midfoot, resulting from a peripheral neuropathy; or collapse of the ankle bones, resulting from trauma or rheumatoid arthritis.

Characteristically, the condition is noted by varying loss of the longitudinal arch. The loss may include: partial or incomplete dislocation of the ankle joint; abduction of the forefoot; or valgus deformity of the rearfoot; or all of the previously mentioned conditions. There may be pronounced pronation, and extreme tenderness of bottom surfaces of the foot. There may also be marked inward displacement, and severe spasm of the Achilles tendon on manipulation, and spasmodic contraction of the lower leg muscles. The posterior tibial tendon may be thickened, swollen, and with increased warmth in the area. The talus may be felt on the bottom, inner aspect of the foot. The extent of the deformity is extremely variable and usually progressive. The condition may exist without causing symptoms or interfering with normal function of the foot.

The condition is diagnosed by a comprehensive history to determine the onset of the condition. The history may determine if there has been a Lisfranc fracture or dislocation, and a primary arthrosis of the affected joint; associated trauma; or if the person has rheumatoid arthritis. X-rays are also used to determine the cause of the deformity.

Treatment may include providing support to the arch and ankle with an orthosis. The type of orthotic device ordered will vary according to the severity of the flatfoot deformity. Care of the skin to prevent breakdown is considered when the person is using an orthotic device. The condition may also be managed surgically.

Residuals may include the permanent use of an orthosis. The device may have to be adjusted periodically. Skin care is ongoing to prevent breakdown of the tissue surrounding the device. If surgical correction of the deformity is performed, residuals will depend on the degree of corrections, and the response of the deformity to surgical interventions.

• The rating schedule for musculoskeletal was updated on February 7, 2021. Protection still does apply and should be considered with existing evaluations (38 CFR 3.951(a)).

• When multiple foot disabilities are present, but the etiology of the symptoms cannot be separated, assign a single disability evaluation for the predominant symptoms. If the etiology of the symptoms can be delineated, separate disability evaluation may be assigned under multiple DCs for foot disabilities provided that the principles of 38 CFR 4.14 have not been violated.

• When SC is established for pes planus and plantar fasciitis (DC 5269), evaluate the symptoms of both conditions together under the DC warranting the highest evaluation for the combined impairment.

• None.