Bunion (Hallux Valgus) Overview
A bunion is a structural change in the foot, resulting in a bone deformity at the great toe joint. The medical name for a bunion is hallux valgus or hallux abducto valgus (HAV).
The 1st metatarsal (seen in the diagram to the right) moves medially, towards the centerline of the body, and the great toe moves laterally, or abducts, towards the small toes. This movement causes a bump to form at the great toe joint.
The great toe joint is also called the metatarsal phalangeal joint or 1st MPJ. The great toe, also known as the hallux, has two bones in it, the proximal phalanx, closer to the metatarsal bone, and the distal phalanx, near the toenail.
In most bunion cases there is also rotation (valgus rotation) occurring, hence the long medical name hallux abducto valgus.
There may be some bone growth at the big toe, but the bump is mostly from the movement of the metatarsal bone. The movement of the bones occurs gradually over time in response to abnormal motion of the foot, abnormal position of the foot, abnormal tendon pull, or tight, narrow shoes. Below is a diagram of a bunion and X-rays of two bunions. Mouse over the X-rays to see the outline of the bones.
In general, it takes a few years for the great toe to move towards the small toes. (In some cases of trauma, this can happen much more quickly). Most people notice the bump on their foot or notice that their big toe has moved before they notice any pain.
The typical complaint of pain is a deep, dull, “in-the-joint” pain. Some experience pain on the top or the side of the toe from shoe pressure. Others experience dull, achy pain after walking, or sharp pain with walking in certain shoes. There can be grinding pain and stiffness is fairly common.
The type of pain depends on the person, what stage the bunion is in, the activity level, and the shoe type. Some individuals never develop pain, despite having severe bunion deformities. In the X-rays pictured above, the bunion on the right looks like it would be much more painful. But, the individual on the left was actually experiencing more pain at the time of the X-ray. (The X-ray on the right shows a toe ring on the 2nd toe).
A combination of factors contributes to the development of bunions. The main factors are genetics, foot type, and shoe gear. Narrow or high-heeled shoes generally do not cause bunions but can contribute to the development of bunions.
Individuals with flat, flexible feet are more likely to develop bunions due to abnormal forces causing an imbalance in the foot (see hypermobility below).
This imbalance results in the movement of the bones, as seen in the X-rays and diagrams above. Women are much more likely to develop bunions than men, generally due to wearing tight, narrow, or high-heeled shoes. Individuals with certain types of inflammatory arthritis, such as rheumatoid arthritis, are more likely to develop bunions.
There are no effective measures that will prevent bunion development, but they are a few conservative treatments that may help slow the progression of a bunion and some treatments which can minimize the pain. Custom-made orthotics can place the foot in the appropriate position and help remove abnormal tendon pull on the bunion, slowing progression.
Custom orthotics tend to be the most effective in individuals with flexible feet and abnormal pronation. Wider shoes, particularly with a wide toe box, will decrease the pressure on the great toe and may eliminate pain and slow progression.
Rigid shoes with a rocker-type sole can eliminate pressure on the forefoot and the great toe joint, minimizing pain when walking. Bunion night splints will not slow progression nor change the structure or shape of the bunion but may help eliminate pressure-type pain while sleeping or walking.
Bunion surgery is not necessarily bunion removal. A bunion is a movement or shift of the bones, which means that the surgery to correct the bunion involves moving the bone back into place. Surgery is only recommended when there is pain that limits daily activities.
This means that the pain limits your ability to do your job, your housework, your hobbies, or your exercise routine. If the pain is rare or there is no pain, surgery is generally not recommended.
Crossover Hammertoe PictureThere are exceptions of course, and when the bunion deformity is severe and causing open sores or a patient is diabetic and there is a concern for ulcer development, surgery may be recommended, even if there is no pain.
Another instance may be when the great toe has moved under the 2nd toe and is causing the 2nd to pop up into a hammertoe. If the hammertoe is causing pain or problems, then the bunion must also be addressed. Cosmetic bunion surgery is not recommended.
The most common type of bunion surgery is surgery at the great toe. This involves breaking the metatarsal bone (called an osteotomy), moving it, and stabilizing it with a screw. Not all surgeons use a screw, some use staples or wires. The goal is to move the head of the metatarsal bone over (literally) in the direction of the small toes.
A tendon is cut in between the great toe and the 2nd toe, to release the great toe and allow it to align with the metatarsal. Other ligaments and some of the joint capsules might also be released to allow the great toe to come back into alignment.
The “V” cut in the bone is called a Chevron osteotomy. It is one of the most common bunion procedures. The “V” cut is made instead of a straight cut because it is more stable. There are many variations of this type of osteotomy. An illustration is shown on the right.
Below are bunion x-ray images before and after surgery. A line is drawn through the center of the metatarsal and the phalanx of the big toe. These lines give an idea of the difference in angle of the bunion deformity before and after surgery.
In the X-ray image to the far right below, the screw placement is more visible and it is easy to see how the joint surface at the great toe joint has lined up.
Most people want to know what the two “blobs” are by the big toe and wonder if they are normal. These are called sesamoid bones. These two bones sit under the big toe joint and act like ball bearings, allowing the tendons to move the big toe up and down smoothly over the metatarsal while walking.
The sesamoids bones can contribute to the bunion deformity and in some cases, one of the sesamoids is removed during surgery if the surgeon feels it is contributing to the deformity.
After Surgery: Post-op Care
The foot is generally wrapped in gauze and Coban™. Coban™ self-adherent wrap is flexible, elastic and adheres to itself, and is commonly used by podiatrists. It is necessary to be in a surgical shoe for 3-6 weeks, depending on the type of surgery that has been done.
As seen in the picture to the left, there is bruising on the toes. This is very common after bunion surgery and is considered normal.
The bandages are initially changed at about 3-5 days after the surgery to check for signs of infection (redness, swelling, and pain out of proportion are signs of infection).
The stitches (if they are not absorbable) are removed at 10-12 days. Most people are back in a regular shoe between 4-6 weeks, but full recovery and a return to normal activities can take a number of months. Stiffness and swelling can persist for 6-12 months.
A tailor’s bunion is also a structural change in the foot. The result is a bony deformity at the 5th metatarsal phalangeal joint. The 5th metatarsal moves laterally and the 5th toe moves medially, as seen below.
The movement results in a structural change and causes a bump to form on the outside of the foot. The bump may be due to an enlarged bone or bone spur, as seen to the right. Like bunions, tailor’s bunions may take a number of years to develop.
Generally, the pain is deep, dull, and achy, but the pain can be sharp with walking. The pain is usually worsened with shoe pressure. Another name for a tailor’s bunion is a bunionette. Mouse over the diagram to the right to see the area identified and labeled.
The treatments are very similar to bunion treatments. Addressing the cause of the tailor’s bunion development is important. Faulty foot mechanics may have contributed to the development and orthotics may be necessary as part of the treatment. If the bump is from a bone spur and/or bursa, simple padding or shoe modifications may help. But, surgery to remove the spur may be necessary.
It is much more common to remove part of the bone on the outside of the metatarsal (exostectomy) on tailor’s bunions than it is to do this procedure on the 1st metatarsal, for a bunion. If the 5th metatarsal has moved out enough, a chevron type osteotomy can be performed to move the head of the metatarsal bone back into place.
Although the procedure described above might be the most well-known type of bunion surgery, it is not the only type of bunion surgery. Bunions that are much more severe or are associated with excess motion (hypermobility) require more advanced procedures.
The procedure should address the problem. In most cases, the problem is excess mobility of the first ray. Although there is a large bump on the side of the foot, the real problem is the mobility of the 1st ray.
Bunion Diagram of motion originating at the 1st metatarsal cuneiform joint
The 1st metatarsal moves up and towards the midline of the body when the calf muscles are tight and there is overpronation. The images to the right demonstrate the motion of the 1st metatarsal toward the midline of the body as the hallux (great toe) moves toward the lesser toes.
It’s important to note where the motion is originating, which is at the midfoot area, not the toe area. Mouse over the image to the left to see the elevation of the 1st ray which is common in bunion hypermobility. Hypermobility of the first ray of the foot contributing to a bunion deformity
Surgical Correction for Hyperobile Bunion
A common procedure to repair a bunion with hypermobility is to fuse the joint where the excess motion originates. The procedure shown below is a fusion of the 1st metatarsal cuneiform joint. This procedure is generally performed when excess motion (hypermobility) of the 1st ray is contributing to the bunion deformity.
Diagram of how a bunion Lapidus procedure is performed Bunion diagram Lapidus procedure with screw placement.
The radiographs to the right show the pre-operative and post-operative views of this procedure. The X-ray on the far left shows a severe bunion deformity.
The X-ray on the right shows the after surgery view. The screws used to fuse the hypermobile joint (so there will be no more excess motion) are visible in the X-ray.
The procedure is shown here also involved correcting hammertoe deformities, which commonly occur with bunions. Hammertoes are also caused by faulty foot mechanics and tendon imbalance.
Bunion X-ray Pre and Post Lapidus Procedure
When there is instability in the midfoot, a joint in the middle of the foot may be fused. The procedure shown above shows the base of the 1st metatarsal fused to the 1st cuneiform. The toes have been straightened at the same time.
Other procedures to address the structural problems in the foot could involve further bone fusions and tendon transfers, with the use of screws, pins, plates, and anchors. The recovering time after more advanced bunion surgery is longer and usually involves a cast and crutches for 6-10 weeks, depending on the surgery.
Regardless of the surgery, the healing process can take 6 months and up to a year for a full recovery. During this time there is generally some swelling and stiffness in the joint. Much of the pain and swelling after surgery is dependent on how well the patient follows instructions. Those who don’t ice and elevate and find themselves on their feet immediately, generally have more swelling, more pain, and a longer recovery period.