A bunion, also known as hallux valgus, is a deformity of the joint connecting the big toe to the

foot The foot ( : feet) is an anatomical structure found in many vertebrates. It is the terminal portion of a limb which bears weight and allows locomotion. In many animals with feet, the foot is a separate organ at the terminal part of the leg made ...

. The big toe often bends towards the other toes and the joint becomes red and painful. The onset of bunions is typically gradual. Complications may include

bursitis Bursitis is the inflammation of one or more bursae (fluid filled sacs) of synovial fluid in the body. They are lined with a synovial membrane that secretes a lubricating synovial fluid. There are more than 150 bursae in the human body. The bursa ...

arthritis Arthritis is a term often used to mean any disorder that affects joints. Symptoms generally include joint pain and stiffness. Other symptoms may include redness, warmth, swelling, and decreased range of motion of the affected joints. In som ...

. The exact cause is unclear. Proposed factors include wearing overly tight shoes, high-heeled shoes, family history, and rheumatoid arthritis. Diagnosis is generally based on symptoms and supported by X-rays. A similar condition of the little toe is referred to as a bunionette. Treatment may include proper shoes, orthotics, or NSAIDs. If this is not effective for improving symptoms, surgery may be performed. It affects about 23% of adults. Females are affected more often than males. Usual age of onset is between 20 and 50 years old. The condition also becomes more common with age. It was first clearly described in 1870. Archaeologists have found a high incidence of bunions in skeletons from 14th- and 15th-century England, coinciding with a fashion for pointy shoes.

Signs and symptoms

Symptoms may include irritation of the skin around the bunion, and blisters may form more easily at the site. Pain may be worse when walking. Bunions can lead to difficulties finding properly fitting footwear and may force a person to buy a larger size shoe to accommodate the width of the bunion. If the bunion deformity becomes severe enough, the foot can hurt in different places even without the constriction of shoes. It is then considered as being a mechanical function problem of the forefoot.

Cause

The exact cause is unclear. It may be due to a combination of internal and external causes. Proposed factors include wearing overly tight shoes, high-heeled shoes, family history and rheumatoid arthritis. The American College of Foot and Ankle Surgeons states that footwear only worsens a problem caused by genetics. Excessive pronation of the foot causes increased pressure on the inside of the big toe that can result in a deformation of the medial capsular structures of the joint, subsequently increasing the risk of developing bunions.

Pathophysiology

The bump itself is partly due to the swollen bursal sac or an osseous (bony) anomaly on the metatarsophalangeal joint. The larger part of the bump is a normal part of the head of the first metatarsal bone that has tilted sideways to stick out at its distal (far) end (metatarsus primus varus). Bunions are commonly associated with a deviated position of the big toe toward the second toe, and the deviation in the angle between the first and second metatarsal bones of the foot. The small

sesamoid In anatomy, a sesamoid bone () is a bone embedded within a tendon or a muscle. Its name is derived from the Arabic word for 'sesame seed', indicating the small size of most sesamoids. Often, these bones form in response to strain, or can be prese ...

bones found beneath the first metatarsal (which help the flexor tendon bend the big toe downwards) may also become deviated over time as the first metatarsal bone drifts away from its normal position. Osteoarthritis of the first metatarsophalangeal joint, diminished and/or altered range of motion, and discomfort with pressure applied to the bump or with motion of the joint, may all accompany bunion development. Atop of the first metatarsal head either medially or dorso-medially, there can also arise a bursa that when inflamed (

), can be the most painful aspect of the process.

Diagnosis

Bunion can be diagnosed and analyzed with a simple x-ray, which should be taken with the weight on the foot. The ''hallux valgus angle'' (HVA) is the angle between the long axes of the proximal phalanx and the first metatarsal bone of the big toe. It is considered abnormal if greater than 15–18°. Last reviewed June 2015 The following HV angles can also be used to grade the severity of hallux valgus: * Mild: 15–20° * Moderate: 21–39° * Severe: ≥ 40° The ''intermetatarsal angle'' (IMA) is the angle between the longitudinal axes of the first and second metatarsal bones, and is normally less than 9°. The IM angle can also grade the severity of hallux valgus as: * Mild: 9–11° * Moderate: 12–17° * Severe: ≥ 18°

Treatment

Conservative treatment for bunions include changes in footwear, the use of orthotics (accommodative padding and shielding), rest, ice, and pain medications such as

acetaminophen Paracetamol, also known as acetaminophen, is a medication used to treat fever and mild to moderate pain. Common brand names include Tylenol and Panadol. At a standard dose, paracetamol only slightly decreases body temperature; it is inferior ...

nonsteroidal anti-inflammatory drug Non-steroidal anti-inflammatory drugs (NSAID) are members of a therapeutic drug class which reduces pain, decreases inflammation, decreases fever, and prevents blood clots. Side effects depend on the specific drug, its dose and duration of ...

s. These treatments address symptoms but do not correct the actual deformity. If the discomfort persists and is severe or when aesthetic correction of the deformity is desired, surgical correction by an orthopedic surgeon or a podiatric

surgeon In modern medicine, a surgeon is a medical professional who performs surgery. Although there are different traditions in different times and places, a modern surgeon usually is also a licensed physician or received the same medical training as ...

may be necessary.

Orthotics

Orthotics are

splints Splints is an ailment of the horse or pony, characterized by a hard, bony swelling, usually on the inside of a front leg, lying between the splint and cannon bone or on the splint bone itself. It may be "hot," meaning that it occurred recently an ...

or regulators while conservative measures include various footwear like toe spacers, valgus splints, and bunion shields. Toe spacers seem to be effective in reducing pain, but there is not evidence that any of these techniques reduces the physical deformity. There are a variety of available orthotics including off-the-shelf commercial products and custom-molded orthotics, which may be prescribed medical devices. (see Figure Two for images of orthotics)

Surgery

Procedures are designed and chosen to correct a variety of pathologies that may be associated with the bunion. For instance, procedures may address some combination of: * removing the abnormal bony enlargement of the first metatarsal, * realigning the first metatarsal bone relative to the adjacent metatarsal bone, * straightening the great toe relative to the first metatarsal and adjacent toes, * realigning the cartilaginous surfaces of the great toe joint, * addressing arthritic changes associated with the great toe joint, * repositioning the sesamoid bones beneath the first metatarsal bone, * shortening, lengthening, raising, or lowering the first metatarsal bone, * correcting any abnormal bowing or misalignment within the great toe, * connecting two parallel long bones side by side by syndesmosis procedure At present there are many different bunion surgeries for different effects. The age, health, lifestyle and activity level of the patient may also play a role in the choice of procedure. Traditional bunion surgery can be performed under local, spinal or general anesthetic. A person who has undergone bunion surgery can expect a 6- to 8-week recovery period during which crutches are usually required to aid mobility. An orthopedic cast is much less common today as newer, more stable procedures and better forms of fixation (stabilizing the bone with screws and other hardware) are used. Hardware may even include absorbable pins that perform their function and are then broken down by the body over the course of months. After recovery long term stiffness or limited range of motion may occur in some patients. Visible or limited scarring may also occur for patients. Bunionectomy

References

External links

*
Textbook of Hallux Valgus and Forefoot Surgery
', links to complete text in PDF files {{Authority control Foot diseases Skeletal disorders Wikipedia medicine articles ready to translate