Foot News

How does a Hammertoe form?
February 4, 2012

Important Points:

· There are many causes of pain in the forefoot.
· Swelling around the joints near the ball of the foot often is caused by a ligament on the bottom of the foot is tears.
· The deterioration and tearing of this ligament can indicate that a hammertoe is forming, the most common deformity of the lesser toes.
· The pain associated with this deformity may resolve although the deformity itself will not go away short of surgery.

Forefoot pain is one of the most frequent problems that I see in my clinic. There is rarely a day that goes by that I do not see someone with pain and swelling in the front portion of the foot. Forefoot pain is pain on the ball of the foot excluding the big toe.  Usually this pain occurs without trauma or other accident. The most common history is swelling and discomfort that occurs at the base of the toe gradually. This may occur with or without deformity. It is usually worse with activity and with certain shoes.

Several things can cause this including stress fractures, Morton’s neuroma, several usually benign tumors, but the most common cause is injury to ligament that is found on the bottom of the joint at the base of the toe, the metatarsophalangeal joint. This condition is not familiar to most nonmedical patients, and is commonly not familiar to many physicians who do not regularly see patients with foot complaints.

crossover toe

Figure 1: Deformity of the toe after a tear in the plantar plate complex tilts away from the injury.

The major ligaments of the metatarsophalangeal joint are located on the bottom and sides of the joint. It is these ligaments that determine the resting position of the joint. The ligaments can weaken and tear. These tears are usually caused by gradual wear due to age, overuse, the shape of the foot, and many other factors. On occasion, the tear can be suddenly caused from a “jamming” type of injury, but often the ligament is abnormal before this injury.

A hammertoe can develop after these ligament tears. The exact deformity that occurs depends upon the way in which the ligament is torn. A tear, which occurs on the outside portion of the ligament, will allow the toe to tilt toward the inside (figure 1). When the ligament tears in this way, the second toe commonly begins to overlap the big toe; this is called a “crossover” second toe and is often associated with a bunion deformity of the big toe. In the same way, a tear on the inside of the ligament will cause the toe to deviate toward the outside of the foot.

plantar plate tear

Figure 2: Deformity of the central portion of the plantar plate allows the sides of the plate to drift away from the center, permitting the metatarsal head to herniate through.

When the tear involves the central portion of the ligament, a typical hammertoe deformity develops (figure 2). This type of deformity occurs at both the metatarsophalangeal joint at the ball of the foot and the proximal interphalangeal joint, the joint in the toe closest to the foot. This deformity often causes a painful prominence over this joint from the acute flexion.

Unfortunately, once these deformities have developed, there is little short of surgery that can be done to correct the deformity. Often however the pain associated with the deformity can resolve without correction of the deformity. There is also no proven way to prevent the deformity from occurring even while in its early stages.

Reasonable treatment of this problem involves various methods of reducing pressure at this joint. These include stretching exercises focusing on the Achilles and hamstring tendons, maintaining proper posture, using stiff soled or rocker soled shoes, and using orthotic pads to offload the painful joints. Injections of steroid or cortisone medication into the joint can be very helpful in the short run to help relieve pain, however its safety and effect on the natural resolution of this problem has not been established. Overall more than half of the people that developed this problem do not require surgery although many will be left with toe deformities that usually are minimally symptomatic.

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–Brett Fink, MD.  Co-author of The Whole Foot Book:  A Comprehensive Guide to Taking Care of your Feet