A hallux abducto valgus deformity, commonly called a bunion, is a deformity characterized by lateral deviation of the great toe, often erroneously described as an enlargement of bone or tissue around the joint at the head of the big toe.
There is disagreement among medical professionals about the cause of bunions; some see them as primarily caused by the long-term use of shoes, particularly tight-fitting shoes with pointed toes, while others believe that the problem stems from genetic factors that are exacerbated by shoe use. Bunions occur when pressure is applied to the side of the big toe (hallux) forcing it inwards towards, and sometimes under or over, the other toes (angulation). As pressure is applied, the tissues surrounding the joint may become swollen and tender. In a survey of people from cultures that do not wear shoes, no cases of bunions were found, lending credence to the hypothesis that bunions are caused by ill-fitting shoes.
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 top.
The term “hallux” or “hallux abducto-valgus” are the most commonly used medical terms associated with a bunion anomaly, where “hallux” refers to the great toe, “valgus” refers to the abnormal angulation of the great toe commonly associated with bunion anomalies, and “abductus/-o” refers to the abnormal drifting or inward leaning of the great toe towards the second toe, which is also commonly associated with bunions. It is important to state that “hallux abducto” refers to the motion the great toe moves away from the body’s midline. Deformities of the lower extremity are usually named in accordance to the body’s midline, or the line bisecting the body longitudinally into two halves. In more severe cases, the hallux continuing in the abductus fashion eventually either overlaps or underlaps subsequent lesser (small) toes especially the second (adjacent toe).
Signs and symptoms
The symptoms of bunions 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.
Having bunions can also make it more difficult to find shoes that fit properly; bunions may force a person to have to buy a larger size shoe to accommodate the width the bunion creates. When bunion deformity becomes severe enough, the foot can hurt in different places even without the constriction of shoes because it then becomes a mechanical function problem of the forefoot.
Illustration depicting a bunion
Bunions are sometimes genetic[dubious – discuss] and consist of certain tendons, ligaments, and supportive structures of the first metatarsal that are positioned differently. This bio-mechanical anomaly may be caused by a variety of conditions intrinsic to the structure of the foot – such as flat feet, excessive flexibility of ligaments, abnormal bone structure, and certain neurological conditions. These factors are often considered genetic. Although some experts are convinced that poor-fitting footwear is the main cause of bunion formation, other sources concede that footwear only exacerbates the problem caused by the original genetic structure.
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 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. Arthritis of the big toe 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 (bursitis), can be the most painful aspect of the process.
Bunions may be treated conservatively with changes in shoe gear, different orthotics (accommodative padding and shielding), rest, ice and medications. These sorts of treatments address symptoms more than they correct the actual deformity. Surgery, by a podiatric surgeon, may be necessary if discomfort is severe enough or when correction of the deformity is desired.
Orthotics are splints or regulators while conservative measures include various footwear like gelled toe spacers, bunion / toes separators, bunion regulators, bunion splints and bunion cushions. There is a variety of available orthotics (or orthoses) including over-the-counter or off-the-shelf commercial products and as necessary, custom-molded orthotics that are generally prescribed medical devices.
A podiatric surgeon performing surgery to remove the bony enlargement and restore normal alignment of the toe joint.
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 cartilagenous 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, and
- correcting any abnormal bowing or misalignment within the great toe.
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. In the case of laser surgery, a narcotic analgesic is typically used. The trend has moved strongly toward using the less invasive local anesthesia over the years. A patient can expect a 6- to 8-week recovery period during which crutches are usually required for aid in 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.