What is a bunion?
A bunion is an abnormal enlargement of the joint due to inflammation of the overlying adventitious bursa, which occurs either at the base of the first or fifth toe. A Bursa is a fibrous sac which occurs between the tendon and the bone. It acts as a small cushion which allows the tendon, as it contracts and relaxes, to move over the bone. A bunion that occurs at the joint at the base of the fifth toe, is commonly called a Tailor’s bunion, whereas when it occurs at the base of the first toe, it is associated with a Hallux Abducto Valgus (HAV) deformity. HAV is a deformity in which the first toe is angulated away from the mid-line of the body, toward the other toes.
What causes it?
Bunions are caused by the mechanical malfunction of the first or fifth metatarso phalangeal joint, which occurs during the weight bearing phase of the walking cycle.
- Abnormal foot mechanics which cause excessive foot pronation.
- Inflammatory disease e.g. Rheumatoid Arthritis.
- Congenital plantarflexed/dorsiflexed 5th ray deformity.
- Neuromuscular disease.
The symptoms associated with bunions vary from person to person. They commonly include pain, swelling and redness. Not all bunions become painful, whereas in some people, certain arthritic conditions can cause severe bunion pain. Ill-fitting shoes (too narrow or tight) DO NOT cause bunions, but they do aggravate and irritate the skin.
How is it treated?
- Strengthening exercises of the abductor hallucis muscles.
- Stretching of the adductor muscle with the aid of a HAV night splint.
- Footwear advice.
- Accommodative shields and padding to protect the bunions.
- Orthoses which will address any structural abnormalities causing abnormal or excessive foot motion.
- Surgery is recommended only if conservative treatment fails.