What Causes Bunions?

Although they may develop on the fifth (little) toe, bunions usually occur at the base of the big toe.  Bunions are often caused by incorrect foot mechanics.  The foot may flatten too much, forcing the toe joint to move beyond normal range.  In some cases, joint damage caused by arthritis or an injury produces a bunion.  And some people are born with the tendency to develop bunions.  If you’re looking at risk of developing a bunion, wearing high-heeled or poorly fitting shoes makes the problem worse.

Types of Bunions

Positional (mild) bunions arise from the growth of new bone.  Structural (severe) bunions result when the joint at the base of the toe shifts position.  Many bunions are combination of both types.

Positional Bunions

As new bone grows, the joint enlarges.  This stretches the joint’s outer covering.  Force created by the stretching pushes the big toe toward the smaller ones.  Eventually, the inside tendons tighten, pulling the big toe farther out of alignment. 

Structural Bunions

When the angle between the bones of the first and second toes is greater than normal, the big toe slants toward the smaller ones.  In severe cases, this may also cause the second and third toes to buckle. 

Physical Exam

To determine the best treatment for your problem, your doctor may ask if and when your bunion causes pain.  Your doctor may also test how far and how smoothly the affected joint moves.  To see if the incorrect foot mechanics is causing your problem, your doctor may watch how your feet rotate and flatten as you walk.


X-rays may be taken of your foot to show the position of the big toe joint.  Your doctor may also want to see whether the bunion is affecting other bones in your foot.

How Are Bunions Treated?

If a bunion is not painful or severe, your doctor may recommend that you wear a different style of shoes. Or you may be prescribed custom-made shoe inserts (orthoses) to control incorrect foot mechanics. Bunion pads maybe used to reduce shoe irritation and discomfort. For painful or severe bunions, outpatient surgery may be recommended.  After surgery, you’ll soon be on your way home and ready for recovery.

Shifting Soft Tissue

To realign the affected joint, any tight tendons on the inside of the toe are released (cut).  New bone that makes up the bunion is shaved away.

Shifting Bone

The most common bunion surgery reduced the angle between the first and second toes.  Bones in the big toe joint are realigned and the bunion is shaved away.  Ligaments and tendons around the joint may be tightened to hold it properly in place.

Removing the Bone

If a structural bunion is severe, a piece of bone is removed from the first metatarsal (the long bone behind the big toe).  Once repositioned, this bone may be held in place with a pin or a screw.  There are many other surgical procedures that can be performed depending on the severity of the bunion deformity.