Download Bunion/Hallux Valgus - Chesterfield Royal Hospital

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Bunion/Hallux Valgus
Pathoanatomy
Bunion (hallux valgus) affects the big toe joint
(1st MTP joint). The proximal phalanx of the
big toe moves outwards making the metatarsal
head prominent on the inner side of the
(Figure: X-ray)
forefoot. This broadens the forefoot. Shoes
therefore rub on this bony prominence creating
thickening and inflammation of the bursa. Also
Bunion is painful and a cosmetic problem.
increase in the deviation of the 1st metatarsal
With severe deformities the big toe pushes the
inwards (metatarsus primus varus) can lead to
second toe upwards creating secondary
hallux valgus deformity.
deformity. These can cause difficulty in
wearing fashionable shoes for women.
X-rays are done to quantify the deformity and
plan treatment.
Treatment
(Figure: picture of bunion)
As time goes on, the constant pressure may
cause the bone to thicken as well, creating an
even larger lump to rub against the shoe.
Wider shoes reduce the pressure on the
bunion. Treatment of hallux valgus nearly
always starts with adapting the shoes to fit the
feet. In the early stages of hallux valgus,
converting from a pointed-toe shoe to a shoe
with a wider toe box can arrest the progression
of the deformity. Bunion pads may reduce
pressure and rubbing from the shoe. Although
toe spacers are used to splint the big toe and
reverse the deforming forces, they are not
effective.
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includes the tight joint capsule and the tendon
of the adductor hallucis muscle. As you can
see, this muscle tends to pull the big toe
inward. The toe is realigned and the joint
capsule on the medial side of the big toe is
tightened to keep the toe straight. Once the
surgery is complete, it will take about 6 weeks
before the bones and soft tissues are healed.
Almost always surgery is required for
symptomatic bunions. There are well over 150
surgical procedures described to treat hallux
valgus. The objective of correction of the
deformity is to remove the bunion, to realign
the bones that make up the big toe, and to
balance the forces so the deformity does not
return.
The angle made between the first metatarsal
and the second metatarsal is used to make
this decision. The normal angle is around 9-10
degrees. If the angle is 15 degrees or more,
the metatarsal will probably need to be cut and
realigned.
In some cases, the far end of the bone is cut
and moved laterally (distal osteotomy).
This effectively reduces the angle between the
Bunion
first and second metatarsal bones. The bone
Version 1
© Chesterfield Royal Hospital NHS Foundation
is held in the desired position with a metal pin
or small screw. In other situations, the first
metatarsal is cut at the near end of the bone
(proximal osteotomy). Nowadays Scarf Akin
osteotomy is the preferred treatment. This
involves longitudinal cutting and realigning of
first metatarsal, cutting the proximal phalanx of
the big toe and releasing the tight structure on
the lateral side of the first MTP joint. This
Trust
Reviewed Date: April 2015
Next Planned Reviewed Date: April 2017
Directorate: Orthopaedics