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Bunion or hallux valgus.
Refers to a deformity of the joint connecting the big toe to the foot.
A similar condition involving the little toe is ref2242ed to as a bunionette.
Other names include hallux abducto valgus, hallux valgus, and metatarsus primus varus.
The big toe often bends towards the other toes.
The joint becomes red and painful.
Bunion onset is typically gradual.
Complications of bunions may include bursitis or arthritis.
Risk factors include wearing overly tight shoes, family history, and rheumatoid arthritis.
Symptoms include: irritated skin around the bunion, pain when walking, joint redness and pain, and possible shift of the big toe toward the other toes.
Blisters may form more easily around the site of the bunion as well.
Exact cause is unknown.
Affects about 23% of adults.
33% of adults have some degree of hallux valgus.
More common in females than males.
Usual age of onset is between 20 and 50 years, but becomes more common with age.
Diagnosis is generally based on symptoms, clinical findings and supported by X-rays.
Treatment includes: Proper shoes, orthotics, NSAIDs, and surgery.
It may require larger shoe sizes to accommodate the width the bunion creates.
Excessive pronation of the foot causing pressure on the inside of the big toe can result in a deformation of the medial capsular structures of the joint, increasing the risk of developing a bunion.
The bunion bump is in part due to the swollen bursal sac or a bone anomaly on the metatarsophalangeal joint.
The major part of the bump is part of the head of the first metatarsal bone that has tilted sideways to become prominent.
Deviation of the big toe toward the second toe is common with bunions, as is there a deviation in the angle between the first and second metatarsal bones of the foot.
The small sesamoid bones found beneath the first metatarsal help the flexor tendon bend the big toe downwards, may deviate over time as the first metatarsal bone drifts away from its normal position.
Bunions may be related to the development of osteoarthritis of the first metatarsophalangeal joint, its diminished and/or altered range of motion, and discomfort with pressure applied to it or with motion of the joint.
Bursitis on the top of the first metatarsal head can also arise a bursa when inflamed.
Bunion can be diagnosed by plain radiography, which should be weight-bearing, showing the hallux valgus angle (HVA) is the angle between the longitudinal axes of the proximal phalanx and the first metatarsal bone of the big toe: considered abnormal if greater than 15–18°.
Hallux valgus angle (HVA) grades:
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.
The intermetatarsal angle (IMA) 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°
Conservative treatment for bunions: changes in footwear, the use of orthotics ,rest, ice, and pain medications such as acetaminophen or nonsteroidal anti-inflammatory drugs.
With persistent discomfort or when severe aesthetic correction of deformity is required, surgery may be necessary.
Orthotic conservative measures include gelled toe spacers, bunion/toe separators, bunion regulators, bunion splints, and bunion cushions.
Surgical procedures for bunions:
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
Bunion surgery can be performed under local, spinal or general anesthesia.
Distal metatarsal osteotomy is widely used to correct mild or moderate hallux valgus with good clinical results in 80-90% of patients.
Distal metatarsal osteotomy is effective for mild to moderate bunion deformity and pain.
Recurrence or undercorrection after osteotomy occurs in 10-14% of cases.
Orthoses are most effective in the early stages of valgus.
Orthotic treated patients have favorable outcomes until 6 months and then the benefit diminishes.
There is a 6- to 8-week recovery period after surgery, during which crutches are usually required to aid mobility.