(See also Overview of Foot and Ankle Disorders Overview of Foot and Ankle Disorders Most foot problems result from anatomic disorders or abnormal function of articular or extra-articular structures (see figure Bones of the foot). Less commonly, foot problems reflect a systemic... read more .)
The usual cause of hammer toe deformity is misalignment of the joint surfaces due to a genetic predisposition toward aberrant foot biomechanics and tendon contractures. Rheumatoid arthritis (RA) Rheumatoid Arthritis (RA) Rheumatoid arthritis (RA) is a chronic systemic autoimmune disease that primarily involves the joints. RA causes damage mediated by cytokines, chemokines, and metalloproteases. Characteristically... read more and neurologic disorders such as Charcot-Marie-Tooth disease (see Hereditary Neuropathies Hereditary Neuropathies Hereditary neuropathies include a variety of congenital degenerative peripheral neuropathies (eg, Charcot-Marie-Tooth disease). (See also Overview of Peripheral Nervous System Disorders.) Hereditary... read more ) are other causes. The 2nd toe is the most common digit to develop a hammer toe deformity (see figure Hammer toe Hammer toe Hammer toe is a Z-shaped deformity caused by dorsal subluxation at the metatarsophalangeal joint. Diagnosis is clinical. Treatment is modification of footwear and/or orthotics. (See also Overview... read more ). Second toe hammer toes commonly result from an elongated 2nd metatarsal and from pressure due to an excessively abducted great toe (hallux valgus deformity) causing a bunion Bunion Bunion is a prominence of the medial portion of the head of the 1st metatarsal bone. The cause is often variations in position of the 1st metatarsal bone or great toe, such as lateral angulation... read more . Unusually long toes often develop hammer toe deformities. Painful corns Calluses and Corns Calluses and corns are circumscribed areas of hyperkeratosis at a site of intermittent pressure or friction. Calluses are more superficial, cover broader areas of skin, and are usually asymptomatic... read more often develop in hammer toe deformity, particularly of the 5th toe. Reactive adventitial bursas often develop beneath corns, which may become inflamed.
Symptoms of hammer toe deformity include pain while wearing shoes, especially shoes with low and narrow toe boxes, and sometimes metatarsalgia Metatarsalgia Metatarsalgia is a general term for pain in the area of the metatarsophalangeal joints. (See also Overview of Foot and Ankle Disorders.) Most common causes include Freiberg disease Interdigital... read more .
Diagnosis of hammer toe deformity is clinical. Joints are examined for coexistent arthritis (eg, RA—see diagnosis of RA Diagnosis Rheumatoid arthritis (RA) is a chronic systemic autoimmune disease that primarily involves the joints. RA causes damage mediated by cytokines, chemokines, and metalloproteases. Characteristically... read more ).
Shoes should have a wide toe box. Toe pads sold in pharmacies also help by shielding the affected toes from the overlying shoe. If conservative measures are ineffective, surgical correction of the deformity often relieves symptoms. If there is accompanying metatarsalgia, over-the-counter or prescription orthotic devices with metatarsal pads and cushioning may help alleviate the pain.