Hallux Valgus (Bunion)

1bunionA bunion is essentially a shift of the toe bones into the improper position causing pain and loss of function. The deformity involves the big toe and the long bone behind the big toe, the 1st metatarsal. Over time, the 1st metatarsal will begin to move towards the other foot (medial) while the big toe will move out of joint towards the 2nd toe (lateral). As the end of the 1st metatarsal bone begins to stick out, it will be under pressure from shoes and the ground. This constant pressure and friction will cause extra bone formation, leading to the bump that is seen on the side of the foot. The big toe will continue to shift towards the second toe causing an unbalanced big toe joint. Over time arthritis can develop in the joint due to the mal-positioned joint. A bunion deformity is always progressive. It will always get worse over time.

Causes:

Bunions are usually a genetic deformity. There is an imbalance of the muscles and the ligaments that are holding the 1st metatarsal in place. As this joint becomes weaker over time, the long metatarsal bone will begin to shift medially. The big toe is then under stress and begins to shift laterally under the pressure of the joint and shoes. Shoes with a tight and narrow toe box can help to create and make a bunion worse over time. High heeled shoes can also worsen and cause a bunion. Patients with a flat foot type (pronation) have a higher chance of having a bunion in the future.

Symptoms:

A bunion deformity does not always have to be associated with pain. Some patients have a very severe deformity and no pain, while others with a mild deformity have severe pain. Patients usually will have pain right over the bump with continued irritation and bruising to the bone from shoe gear and the ground forces. As the deformity progresses, pain will then be noticed in the joint itself when the big toe is moving. The big toe is very important during the gait cycle for pushing off the ground. With this imbalance of the joint there is a loss of the proper range of motion of the big toe joint leading to an inefficient gait. Over time arthritis will develop in the joint as the cartilage is scraped away each time the joint moves. The pain can be of different degrees depending on the degree of deformity, shoe gear, and activity level.

Diagnosis:

A clinical examination of the foot is done first. It is very important that the structure and biomechanics of the patient’s entire foot is examined. In order to identify the severity of the deformity, the stability of the joints around the bones involved is essential. The doctor will analyze the gait pattern of the patient. The doctor will identify if there is pain with joint movement and if the big toe can easily be re-located back into the joint. X-ray evaluation is essential in order to determine the degree of the bone shift and specific angles and the relationships between the bones.       

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Intermetatarsal angle measurement is used to see the shift of the 1st metatarsal from the second metatarsal for bunion correction decision making.

Hallux abductus angle measurement is used to measure the shift of the great toe towards the second toe for bunion correction decision making.

Treatment Options:

Conservative treatments for bunions are limited. Wider shoe gear and accommodation for the deformity can be used to take the pressure off the area. Bracing and spacers are often used to brace the big toe back into position and can take some of the pressure of the big toe. However, this does not address the deformity and shift in the metatarsal bone. Furthermore, the bracing techniques are only work when used, once the brace is removed, the big toe will immediately go back into its deformed position. Custom molded Orthotics can take some pressure off the big toe and redistribute the forces of the ground through the rest of the foot. Orthotics can slow the progression of the deformity. There is no way to stop the progression or reverse the deformity without literally moving the bones back into the correct position and realigning the joint. This can only be accomplished through surgery.

Many years ago, it was thought that bunions were overgrowths of bone. Removal of the painful bunion or “bump” prominence resulted in improvement for only a short period of time and the bunion would return rapidly because the joint was not realigned. Now we know that in order to realign the joint, the first metatarsal must be repositioned and fixated in the proper position. This can be accomplished by three basic types of procedures.

The choice of the procedure to be performed will be dictated by the severity of the deformity.

Mild Bunion Deformity:

In mild and moderate bunion cases, we try to allow patients to have a more rapid recovery and limit the amount of time they need to spend off their feet. The Tightrope and Offset Austin bunion procedures allow immediate weight on the foot in a boot and also allow for rapid return to shoes. The choice of procedure best for each patient depends on the deformity size, the stiffness of the 1st metatarsal and the ease of realignment of the 1st metatarsal during the clinical exam.

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In a mild bunion case, the Tightrope procedure allows us to realign the 1st metatarsal without having to cut the bone. The tightrope is made out of a metal cord material that is almost impossible to tear. The Tightrope cord is secured via small holes in the 1st and 2nd metatarsal bones with a small metal anchor that holds the cord in place while the bone grows around allow secure correction of the bunion.
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Bunion deformity with shift of the 1st metatarsal with poor alignment of the foot prior to surgery. In a supple 1st metatarsal with easy re-positioning, the Tightrope can be used with excellent an outcome. Tightrope bunion procedure with re-alignment of the 1st metatarsal and the great toe position. Note metal anchors securing the Tightrope cord in place between the two bones.
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Drawing of a bunion prior surgery. Note poor alignment of the great toe and the 1st metatarsal. Grey shaded are will be removed during surgery and dotted line shows the region of bone cut. Drawing of bunion after surgery. Note the shift of the 1st metatarsal towards the second metatarsal for realignment of the column and fixation of the bones together with the two screws from top to bottom.
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X-ray of a mild bunion with small angle between first and second metatarsal and between the first metatarsal and the big toe. Basic correction with screw fixation after the head of the bone has been shifted and the angle closed.
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Pre-operative x-ray showing small angle between the first and second metatarsals and between the first metatarsal and the big toe. Picture showing clinical appearance of a mild bunion.
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Post-operative x-ray showing closed angle between the first and second metatarsals and between the first metatarsal and the big toe after bone cut and screw fixation. Picture showing clinical appearance after surgical correction.

 

Severe Bunion Deformity:

In severe bunion cases, the 1st metatarsal is dramatically shifted away from the second metatarsal and there is looseness of the 1st metatarsal at the base of the bone. This is a difficult problem to correct unless the entire 1st metatarsal is realigned and held stable so it does not shift again. The Lapidus procedure allows for the 1st metatarsal to be repositioned with ideal correction and limited to no chance of bunion return. Recovery is slightly more difficult due to the need for crutches but the result is well worth it in difficult and severe cases.

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X-ray of a severe bunion with large angle between the first and second metatarsal and between the first metatarsal and the big toe. Clinical photo of a severe bunion deformity. Note the rotation of the great toe and pressure on the second toe. Also note the redness of the bunion site.
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Elevation of the 1st metatarsal is noted
(Yellow line is ideal, while red is 1st metatarsal)
The first metatarsal is brought down to the ground for ideal alignment and added foot stability. This not only corrects the bunion, it also adds stability to the arch and allows for better arch support and foot contour.
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Correction of a severe bunion at the first metatarsal cuneiform joint. The large angles are reduced and the instability permanently stabilized. Picture showing clinical appearance after surgical correction.

The underlying cause of severe bunions is thought to be at the medial cuneiform joint and not at the great toe joint. If there is looseness of the medial cuneiform joint, there is motion of the metatarsal allowing the metatarsal to move out of position resulting in a bunion. The metatarsal may also move up resulting in poor position on the ground and collapse of the arch.

The most important part of bunion surgery is the proper procedure selection. This is done with a patient exam and x-rays of the foot that are done on your first visit. The proper procedure is selected based on how big the bunion is and how loose the bunion is. In simple cases, the Tightrope and Offset Austin allow for immediate weight in a boot and return to tennis shoes in 3 to 4 week. More complex cases including those requiring more stability are done with the Lapidus procedure. Although the recovery is slightly longer with the Lapidus procedure, there is no chance of the bunion coming back and foot stability is dramatically increased.

The surgery is done with the use of screws or an anchor in all cases to allow rapid healing and less pain from bone movement. There is usually excellent motion of the toe with no limitations of activity or loss of foot function noted. The scars are closed with plastic surgery techniques to limit scarring and hidden on the side of the foot for better cosmetic healing. With excellent technique and proper procedure selection, bunion surgery can be both simple to recover from and highly successful with little to no pain.