Because of the constant and heavy use of feet by humans as bipeds, they are prone to many problems. In spite of what is commonly believed, most cases of foot bone and joint abnormalities are developmental in origin instead of being caused by poorly fitting footwear.
Developmental, muscle, and bone disorders of the feet.
Clubfoot, also called talipes, is one of the developmental, or congenital, disorders affecting the feet. It occurs in approximately one of every one thousand live human births and is characterized by deformities such as the foot turning down and under, such that a child will walk on the top of his or her foot. Over time, tendon and ligament contraction reinforces the deformity; thus, either casting or surgery is needed for realignment.
Flat foot, or pes planus, is an abnormally flat arch in the foot, accompanied by a characteristic gait, both of which can occur in varying degrees. Muscle weakness, incorrect weight-bearing, a short Achilles tendon, and developmental defects may all contribute to this deformity. Flat foot may or may not produce a pathologic condition such as arthritis.
A bunion is the relocation of bone from the first metatarsal to the inner portion of the joint connecting it to the big toe. This prominence at the base of the big toe makes the soft tissue in the area subject to pressure from shoes, causing swelling and pain in the protective sac above the metatarsophalangeal joint in a condition called
bursitis. Cortisone injections may relieve symptoms, but surgery is required in extreme cases to realign the first metatarsal. Flat foot usually accompanies bunions and is a factor in their development.
Muscular imbalances inherent in the foot are the reason for the curvature of the individual bones of the toes. Abnormally curved bones produce hammertoe, or claw toe, which usually requires little treatment other than a padding of the shoes to avoid corn or callus development. Excessive muscle tension at the heel can produce bony growths called heel spurs or calcaneal exostoses. Inflammation may develop in a neighboring joint’s bursa, causing a throbbing pain.
Inflammation of the calcaneus or heel bone can occur in childhood while the heel is still fusing from the two bones that constitute the heel. When a piece of separated bone, called an apophysis, becomes inflamed, apophysitis occurs. This condition can injure the connecting, softer cartilage between the two, not-yet-connected, bones. Apophysitis usually disappears as children grow and the heel fuses whole.
Nerve and skin disorders of the feet.
Factors including footwear, the structures of the foot itself, and harmful external forces acting on the foot may all contribute to irritation and/or damage to the nerves of the foot. Morton’s neuroma is the thickening of the nerve located between the metatarsals of the third and fourth toes, followed by the formation of a small benign tumor. Painful burning, numbness, or tingling sensations may be alleviated by wearing more comfortable footwear or by the surgical removal of the tumor. Tarsal tunnel syndrome occurs when a nerve traveling along the bottom of the foot through a channel called the tarsal canal becomes compressed and damaged. Cortisone injections into this canal can relieve pressure on the nerve, and surgery can be used to treat severe cases.
The skin of the foot is subject to much pressure and rubbing; thus, it responds by producing changes, termed dermatologic disorders, which themselves cause pain. A corn, or heloma, is a small, sharply defined, raised area of thickened skin containing much of the fibrous protein called keratin. Calluses are also composed of keratin but are flatter and do not possess the defined borders of corns. Both types of thickened keratinized skin are usually attributed to incorrect positioning of the underlying bone.
Warts, or verrucae, are actually skin tumors caused by the human papillomavirus. They occur most commonly on the sole of the foot, where they are named plantar warts. Warts can be transmitted from person to person, and the lymphatic communication between warts within an individual explains their ability to spread. Warts on the foot are invariably benign, however, and should not be treated with x-ray or radium therapy lest the surrounding areas undergo change themselves and eventually produce tumors.
Dermatitis venenata is often caused by chemicals used in the binding or dyeing of shoes. Angiokeratoma is a lesion on the bottom of the foot commonly mistaken for a wart. Fibroma is the name of the benign growth that may spread under the toenails as a result of insect bites in the vicinity or manifestations of other skin diseases.
Ingrown toenails
, or onychocryptoses, occur when the free end of the toenail penetrates the surrounding soft tissue. Reasons for this painful disorder are commonly badly fitted footwear, nail disease, and foot or nail structural abnormalities.
Systemic diseases affecting the feet.
Rheumatoid arthritis is a condition involving connective tissue, unknown in origin, in which the synovial
membrane of joints proliferates while invading and even destroying cartilage and bone. Women acquire this disease three times more often than do men. Steroid hormones are sometimes applied to aid in the treatment of rheumatoid arthritis, but gold salt injection is the only therapy resulting in a permanent cure. The chances of a cure are greater when this disease occurs in children. The condition is then known as juvenile rheumatoid arthritis, or Still’s disease.
Several normally fatal diseases may accompany rheumatoid arthritis. Systemic
lupus erythematosus can be masked by the arthritic condition until inflammation spreads to small arteries of the body’s organs. Polyarteritis nodosa also involves arteries throughout the body, and its true diagnosis may be prevented by the misleading arthritic condition.
Scleroderma involves the thickening of the skin on the face, hands, and feet; depigmentation; loss of hair; and lesions.
Sarcoidosis manifests itself in the hands and feet and causes microscopic lesions in the bone that eventually become visible by x-ray examination. Henoch-Schönlein syndrome is an allergic reaction that can resemble the synovitis of rheumatic fever.
Rheumatic fever affects fibrous tissues in a widespread fashion involving the joints and later the heart. It is related to
streptococcal infections and occurs as a migrating arthritis producing no lasting joint damage in the feet, but it can cause permanent damage to the cardiac valve.
Osteoarthritis causes the degeneration of cartilage and the overgrowth of bone surfaces. The effects of this condition are limited to the joints, unlike rheumatoid arthritis, which can spread to nearby cartilage and bone. Staphylococci, streptococci, and coliform bacteria are the infective agents involved in pyogenic arthritis. In this condition, the organism is carried by the blood to the joint interior. Ulcers of the feet may be caused by a variety of conditions, including diabetes mellitus, syphilis, anemia, and
leprosy.
If there is sustained pain in the foot or ankle with no known cause such as injury, a continuously low leukocyte count, and negative laboratory tests for the presence of bacteria, then a viral infection is likely present. An elevated leukocyte count is often indicative of a bacterial infection.
American Podiatric Medical Association. http://www .apma.org.
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