Foot

A large number of bones, ligaments, muscles, and tendons work in concert to provide stability and flexibility through a range of activities.

Disorders of the Foot and Ankle:

Articular
Arthritis	RA, OA, PsA, gout
Toe disorders	Hallux valgus, hallux rigidus, hammer toe
Arch disorders	Pes planus, pes cavus
Periarticular
Cutaneous	Corn, callosity
Subcutaneous	RA nodules, tophi
	Ingrowing toenail
Plantar fascia	Plantar fasciitis
	Plantar nodular fibromatosis
Tendons	Achilles tendinitis
	Achilles tendon rupture
	Tibialis posterior tenosynovitis
	Peroneal tenosynovitis
Bursae	Bunion, bunionette
	Retrocalcaneal, retroachilleal, and subcalcaneal bursitis
	Medial and lateral malleolar bursitis
Acute calcific periarthritis	Hydroxyapatite pseudopodagra (first MTP)
Osseous
Fracture (traumatic, stress)
Sesamoiditis
Neoplasm
Infection
Epiphysitis (osteochondritis)	Second metatarsal head (Freiberg disease)
	Navicular (Köhler disease)
	Calcaneus (Sever disease)
Painful accessory ossicles	Accessory navicular
	Os trigonum (near talus)
	Os intermetatarseum (first and second)
Neurologic
Tarsal tunnel syndrome
Interdigital (Morton) neuroma
Peripheral neuropathy
Radiculopathy (lumbar disk)
Vascular
Ischemic	Atherosclerosis, Buerger disease
Vasospastic disorder (Raynaud disease)
Cholesterol emboli with “purple toes”
Referred
Lumbosacral spine
Knee
Reflex sympathetic dystrophy syndrome
MTP, metatarsophalangeal; OA, osteoarthritis; PsA, psoriatic arthritis; RA, rheumatoid arthritis

Achilles Tendinitis

Is caused by repetitive trauma and tendon microtears due to excessive use of the calf muscles, as occurs in ballet dancing; track and field, including distance running and jumping; or from faulty footwear with a rigid shoe counter. Enthesopathy and insertional Achilles tendinitis may also occur in patients with ankylosing spondylitis (AS) or psoriatic arthritis (PsA). The tendon is a common site for gouty tophi, rheumatoid nodules, and xanthomas.

Achilles tendon rupture

Occurs most commonly in active young men, during a burst of unaccustomed physical activity involving forced ankle dorsiflexion or from intense athletic activities, particularly football, basketball, or tennis. It may also occur after minor trauma in elderly individuals with preexisting Achilles tendinitis, in patients with systemic lupus erythematosus or rheumatoid arthritis (RA) who are receiving corticosteroids, or after local corticosteroid injection near the Achilles tendon.

Retrocalcaneal, sub-Achilles, or subtendinous bursitis

Is characterized by posterior heel pain that is aggravated by both activity and passive dorsiflexion of the ankle. Patients may develop a limp, and wearing shoes becomes painful. May be associated with SpA

Retroachilleal or subcutaneous calcaneal bursitis

also called a pump bump, produces a painful, tender, subcutaneous swelling overlying the Achilles tendon, usually at the level of the shoe counter, and the overlying skin may be hyperkeratotic or reddened. It occurs predominantly in women and is frequently caused by wearing improperly fitting shoes or pumps with a stiff, closely contoured heel counter.

Ankle sprain

Is one of the most common sports-related injuries. Most cases will heal spontaneously with supportive therapies.

Plantar fasciitis

Is the most common cause of subcalcaneal heel pain. It results from repetitive microtrauma, which causes microtears of the plantar fascia at its attachment into the medial calcaneal tuberosity. Risk factors include repetitive trauma from athletic activities, occupations that entail excessive standing and walking, changes in footwear, reduced ankle dorsiflexion (< 10°), obesity, and pronated everted flat foot (pes planovalgus). It may also occur in association with AS or PsA.

Painful calcaneal fat pad (painful heel pad syndrome)

Is often confused with plantar fasciitis. The heel pad is normally composed of fibroelastic septa separating closely packed fat cells. Rupture of the septa in elderly, obese patients, during everyday activities or as a result of a sudden severe impact, results in attrition of the heel pad, poor shock absorption, and increased weight-bearing pressure on the calcaneus with reactive bony proliferation. Subcalcaneal heel pain occurs on weight bearing, with tenderness over the heel pad at the posterior weight-bearing portion of the calcaneus.

Bilateral plantar and calcaneal traction spurs

Are common in obese, stout, middle-aged and elderly individuals. Traction spurs are radiological findings and are frequently asymptomatic, although heel pain may result from a coexistent plantar fasciitis, Achilles tendinitis, or painful heel pad.

Flat foot (pes planus)

Is often asymptomatic but may result in muscle aching with prolonged standing or walking. Loss of the medial longitudinal arch on weight bearing and plantar displacement of both the navicular and the talus are the main findings.

Metatarsalgia and Morton Interdigital Neuroma

Metatarsalgia is a common symptom with diverse causes. It often appears after years of misuse and weakness of the intrinsic muscles due to chronic foot strain from improper footwear. Pain in the forefoot on standing or walking and tenderness of the metatarsal heads and MTP joints are the main clinical findings. Plantar calluses and clawed toes are frequently present. Morton interdigital neuroma often results from chronic foot strain and repetitive trauma caused by inappropriately fitting shoes or from mechanical foot problems, such as pronated flat foot or pes cavus. It represents an entrapment neuropathy of an interdigital nerve, rather than a true neuroma, typically between the third and fourth, or the second and third, metatarsal heads. The nerve is entrapped under the transverse metatarsal ligament or by an intermetatarsophalangeal bursa or a synovial cyst.

Tarsal tunnel syndrome

This syndrome occurs when the posterior tibial nerve is compressed at the flexor retinaculum, located posterior and inferior to the medial malleolus. A positive Tinel’s sign (obtained by percussing posterior to the medial malleolus) and a positive tourniquet test (applying pressure over the flexor retinaculum) will often reproduce the symptoms. Holding the ankle for 10 seconds in dorsiflexion and eversion will also exacerbate symptoms. This occurs more often in women and is associated with trauma, fracture, valgus deformity, hypermobility, inflammatory arthritis (up to 25% of patients with RA), diabetes, and occupational factors. Treatment consists of antiinflammatory medications, local steroid injection, and orthotics. Surgical release is indicated when conservative measures fail.

Hallux valgus

Refers to a lateral deviation of the great toe on the first metatarsal greater than 10° to 15°. It is more common in women and is often caused by a combination of genetic predisposition and the wearing of narrow, high-heeled, or pointed shoes. Other causes include congenital splay-foot deformity; metatarsus primus varus, an increased intermetatarsal angle greater than 9°, with or without metatarsus adductus of the adjacent second and third metatarsals; RA; and OA. Hallux valgus is often asymptomatic.

Hallux Limitus and Hallux Rigidus

Hallux limitus refers to painful limitation of dorsiflexion of the first MTP joint. Hallux rigidus is a marked limitation of movement or immobility of the first MTP joint, usually because of advanced OA.

Bunionette, or tailor’s bunion

Is a painful callus and/or adventitious bursa overlying a prominent, laterally deviated fifth metatarsal head (metatarsus quintus valgus) and a medially deviated fifth toe. The pain is made worse by activity and by constricting footwear. It often occurs in conjunction with hallux valgus and forefoot splay. The intermetatarsal angle between the fourth and fifth metatarsals is greater than 10° (normal is 6.5° to 8°), and the fifth metatarsophalangeal angle is greater than 16° (normal < 14°).

Hammer toe

Deformity most commonly affects the second toe. It is characterized by flexion deformity of the PIP joint, associated with dorsiflexion of the MTP and DIP joints. A painful corn often develops over the dorsal prominence of the PIP joint. Leading causes include ill-fitting footwear, trauma, RA. It may also be a congenital deformity.

Specific Disorders of the Ankle and Foot

Gout and Other Crystal Arthropathies

Redness, swelling, and pain at the great toe MTP is the most common initial presentation of gout. The intense redness spreading into surrounding soft tissue can sometimes be confused with cellulitis. The midtarsal and hindfoot joints can also be affected by crystal arthritis.

Osteoarthritis

The MTP joints, especially of the great toe, are frequently affected by osteoarthritis. Cock-up toes and hallux valgus and rigidus due to osteoarthritis are some of the most common foot problems.

Psoriatic Arthritis and Other Seronegative Diseases

Enthesopathy and synovitis affecting the ankle and foot region are often seen in seronegative arthritis. Dactylitis (“sausage toe”) is considered a hallmark of this group of conditions.

Rheumatoid Arthritis

Rheumatoid arthritis can affect the hindfoot, midfoot, and forefoot (the most common site). Poor control will lead to joint destruction and deformities. Of particular concern is a rupture of the tibialis posterior tendon, which results in a collapsed midfoot with forefoot abduction and hindfoot valgus.

Selected Readings:

J.S. Gould: Metatarsalgia. Orthop. Clin. North Am. 20:553-562 1989 PIMD: 2797750

M.F. Mazzone, T. McCue: Common conditions of the Achilles tendon. Am. Fam. Physician. 65:1805-18102002 PIMD: 12018803

M.M. Stephens: Haglund’s deformity and retrocalcaneal bursitis. Orthop. Clin. North Am. 25:41-46 1994 P;ID: 8290230

K.K. Wu: Morton neuroma and metatarsalgia. Curr. Opin. Rheumatol.. 12:131-142 2000 PMID: 10751016

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Images

Web:

Acquired Flatfoot (Pes planus) - AAOS (US)

American Colle of Foot Suregeons

Children With Talips (Clubfoot) - (NHS UK)