Flatfoot In Adults

Modern Study Review (AI-Generated)

High-Yield Summary

Adult flatfoot is a common deformity with a broad clinical spectrum ranging from asymptomatic flexible flatfoot to rigid, painful deformities often caused by posterior tibial tendon dysfunction (PTTD) or tarsal coalition. Accurate diagnosis and differentiation between flexible and rigid types are essential for guiding treatment. Contemporary management prioritizes symptom relief and functional restoration, with nonoperative care as first-line for most cases and surgery reserved for refractory or severe deformities.

Key Diagnostic Findings

Current Gold Standard Treatment

Modern Complications & Outcomes

Complications:

• Overcorrection or undercorrection leading to persistent pain or deformity.
• Nonunion or malunion after arthrodesis.
• Adjacent joint arthritis following fusion procedures.
• Tendon rupture or failure of tendon transfers.
• Recurrence of deformity in neuromuscular or dysplastic conditions.

Outcomes:

• Early-stage PTTD responds well to orthotics and physical therapy with good pain and function improvement.
• Surgical correction improves pain and function but requires careful patient selection due to risk of complications.
• Resection of calcaneonavicular coalition provides good pain relief if done before degenerative changes.
• Kidner procedure reliably alleviates symptoms of accessory navicular syndrome.
• Residual congenital deformities have guarded prognosis; surgery is complex and individualized.

Classic Clinical Notes

Flatfoot in Adults

Reference: Mann, Roger A, Flatfoot in Adults, in Surgery of the Foot and Ankle, 6th ed, Mann & Coughlin ed., Mosby, 1993

Main Message

• Most flatfeet are asymptomatic and require no treatment.
• Beware taking on surgical treatment of flatfeet!

Points of Interest

• A spectrum exists.
• Pain may be related to overuse, and the x-ray appearance may be irrelevant.
• In general, it is unusual for an adult with a flexible flatfoot to become symptomatic.
• Can think of it in two ways: Congenital and Acquired.

Congenital:

• Asymptomatic flexible flatfoot
• Symptomatic flexible flatfoot
• Tarsal coalition
• Accessory navicular
• Residua of congenital deformity
• clubfoot, vertical talus
• Generalized musculoskeletal dysplasia
• Marfan’s

Acquired:

• Posterior tibial tendon dysfunction
• Charcot joint – diabetes, peripheral neuropathy
• Arthritis – talonavicular, tarsometatarsal, rheumatoid
• Post traumatic
• Neuromuscular – polio, cerebral palsy, nerve injury
• Tumor

Asymptomatic Flexible Flatfoot

• common; normal variant
• physical exam demonstrates inversion of heel when up on toes, normal subtalar, ankle, and tarsometatarsal motion.
• xrays show a talo-metatarsal angle of 15° (normal is 0°)
• Approach: generally speaking – no treatment

Symptomatic Rigid Flatfoot

• underlying pathology is the Achilles tendon! They get a tight Achilles, which puts them into equinus and stresses the transverse tarsal joint, which eventually gives in and a “rocker bottom” deformity is created.
• full inversion of the hindfoot does not occur when up on toes; probably secondary to joint changes after the midfoot break.
• both dorsiflexion and plantarflexion are decreased, but the underlying problem is in the reduced dorsiflexion
• xrays show an increased talo-metatarsal angle, decreased calcaneal pitch
• Approach: conservative – arch supports and firm heel counters, custom orthotics, UCBL orthosis
• if only absolutely necessary, surgery would include a triple arthrodesis with tendo-achilles lengthening; BEWARE!! The chances of making them worse are high!

Tarsal Coalition

• usually becomes symptomatic in adolescence
• in adults, a history of trauma (mild) is common – probably busts off a synchondrosis
• physical may reveal a normal longitudinal arch! No inversion of the heel is seen on standing.
• xrays may show beaking of the talus, flattening of the arch, and the coalition
• two most common are calcaneonavicular and talocalcaneal
• Approach: in acute injury – cast, 6 weeks, then try orthosis
• if no response, surgery
• calcaneonavicular bars should be resected early before secondary degenerative changes occur. The resection is for pain relief, not for flexibility – the subtalar motion will continue to be poor.
• talocalcaneal coalition should be fused

Accessory Navicular

• rarely symptomatic in adults (they have had a flatfoot deformity since a kid)
• often become symptomatic after a minor trauma
• physical reveals the medial prominence (maybe tender) and varying degrees of a sagging longitudinal arch, satisfactory motion at the ankle, subtalar, and transverse tarsal joints
• inversion of the calcaneus does occur when standing on toes
• xrays show the accessory navicular – in adults, it is more likely to be a synchondrosis that was asymptomatic until injured.
• Approach: short leg cast for 4-6 weeks
• if continues to be symptomatic, try Kidner procedure to resect the accessory navicular and plicate the tib post.

Residual Congenital Deformities – Clubfoot, Congenital Vertical Talus

• very difficult
• remember that fusing is tempting, but the forces go elsewhere in the foot/ankle!

Generalized Dysplasia – Marfans, Ehlers-Danlos

• remember that soft tissue procedures will likely not work, because their soft tissues are the problem.
• Approach: try to treat nonoperatively with an orthotic or well-fitted firm shoe. If necessary; triple arthrodesis is their most likely surgical option.

Last Updated on January 24, 2026 by Christian Veillette