Adult Flatfoot – Pes Planus Deformity
Description:
o Progressive
flattening of medial longitudinal arch
o Was not
present at birth (congenital flatfoot)
o Gait
abnormality – excessive hindfoot valgus with initial ground contact
o Abduction
of forefoot
o Foot
fatigue from inadequate support of longitudinal arch
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Above: From left to right,
cavus deformity, normal foot, pes planus (flatfoot) deformity |
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Etiology:
o Posterior
tibial tendon dysfunction
o Arthrosis
(fusion) of tarsometatarsal (TMT) joints
o Charcot
changes in midfoot due to peripheral neuropathy
o Talonavicular
collapse from rheumatoid arthritis or trauma
o Usually no
history of trauma
o Possible
history of Lisfranc injury
Symptoms & Signs:
o Abducted
forefoot
o Tiptoe
standing – calcaneus remains in valgus, instead of normal inversion
o Too many
toes sign
o Decreased
or no active inversion strength
o Swollen,
tender posterior tibial tendon
o Prominent
medial cuneiform
o Charcot
foot has variable swelling and deformity
o Rhematoid
arthritis foot has a fixed valgus deformity of the hindfoot
Imaging:
o Radiographs
usually elucidate cause of flatfoot deformity:
o Posterior
tibial tendon dysfunction - sagging talonavicular joint or abduction of
navicular on head of talus
o TMT
arthrosis - joint degeneration and lateral and dorsal subluxation
o Charcot
foot – dramatic joint destruction and dislocation
- Rheumatoid foot – typical destructive, erosive
changes with loss of bony architecture
Treatment:
Conservative
- Support the longitudinal arch and ankle
- Ankle-foot orthosis (AFO)
- Must be shaped to accommodate any bony
prominences to avoid skin breakdown
Surgical treatment
- Depends on specific cause of flatfoot deformity:
- Posterior tibial tendon dysfunction =
reconstruction of tendon with flexor digitorum longus tendon
- Possible calcaneal osteotomy if significant
valgus deformity
