foot pain causes

Article on Forefoot Pain Types, Causes, and Cures

- by John Robertson, MD

Consider the simple fact that running involves each foot hitting the running surface several thousand times each mile. It's easy to understand that the most common problems that virtually all runners must eventually contend with is pain in the foot. Especially in that front half of the foot, the portion that includes the toes and metatarsal bones. Most runners strike the ground toes first, or at least flatfooted, then after a brief time on the ground, push off with the ball of the foot and the toes, resulting in a tremendous amount of cumulative impact trauma.

I suspect that every athlete that has some form of running or jumping involved in their sport will have, at one time or another, problems with their forefoot, whether it be as benign as a blister or as troublesome as a stress fracture. This month we'll cover some of the most common maladies that befall all of us who use our feet for fitness, fun or work. A partial list of the most common offenders include: neuroma, callus, bunions at the big or little toe, second toe instability at the ball of the foot, hammertoes or claw toes, hard or soft corns, a rigid first toe called hallux rigidus, sesamoid problems and finally, stress fractures. We'll go over each of these individually.

A neuroma, which is an enlargement of the nerve as it travels between the bones at the base of the toes that form the ball of the foot, causes ill-defined pain in the toes, usually the 3rd and 4th, and occasionally the 2nd and 3rd toes (in the medical world, the big toe is number one and the little toe is number five.) Nerve-like pain is common, worsening with activity and improving when shoes are removed. Numbness is common in the same distribution as the pain. Squeezing the toes together is often painful and the diagnosis is confirmed if an injection of local anesthetic relieves the pain. Treatment involves wearing shoes with a wider toe box, placing a metatarsal pad on the ball of the foot just toward the heel, and anti-inflammatory meds is the first round of treatment, with injections of cortizone next and surgery as a last resort. Fortunately, most respond to the more conservative measures.

Callus tends to form at pressure points between the foot and the shoe, and if it is located on the ball of the foot, beneath one or more of the heads of the nearby metatarsal bones. The more pinpoint or discrete callus may be caused by an enlarged portion of bone at that particular toe. Because of the bony anatomy, this particular form of callus can become quite stubborn and difficult to treat without surgically removing the offending bone. Callus must be differentiated from warts, which can look exactly the same. One way of distinguishing the two is to simply shave off the top gently. A wart has a blood supply and will bleed, whereas callus does not.

Treatment involves removing the callus with a nail file or pumice stone or having a podiatrist remove it professionally. Once the majority of the callus is removed, weekly rasping after a shower will usually keep them under control. A metatarsal pad placed under the ball of the foot just towards the heel will help distribute the weight, and thus pressure, more evenly. If the pain is persistent despite the above measures, surgical consideration for removal of the bony spur is considered.

Bunions may form at either the first, or big toe, or at the fifth toe. At the fifth toe, a callus forms at the ball of the foot as a result of friction between a bony prominence there and the shoe. Simply changing shoes or stretching the shoe in that location may suffice to improve the situation. There are several surgical solutions available for resistant problems, depending on the particular anatomical set-up.

A bunion at the big toe occurs in those who inherit a tendency towards the problem and is aggravated by wearing pointy-toed shoes. The big toe begins to angulate or point toward the smaller toes and progressive enlargement of the bony surface and overlying bursa results in a bunion that may become quite painful, swollen and inflamed. If a sensory nerve on top of the toe is entrapped, numbness or tingling may also occur.

When evaluating a symptomatic bunion for possible surgery, weight-bearing X-rays are useful for checking the various bony alignments in the forefoot and for the presence of any associated arthritic or degenerative changes. There are multiple surgical options available; the choice depends upon the above anatomical factors for each particular foot. Non-surgical options focus upon proper shoe selection with a high, wide toe box and soft leather uppers to accommodate the enlargement at the great toe. Many people actually get by just fine without surgery, even with a fairly prominent bunion deformity.

Generally, any pain in the forefoot area is loosely termed metatarsalgia, which simply means "forefoot pain." The term is not specific since many variable conditions can create forefoot pain. It's much like the term "shin splints" which refers to any pain from the knee to the ankle and is not specific as to the diagnosis.

One of the more subtle causes of metatarsalgia is subluxation of the joints at the ball of the foot, called metatarsal-phalangeal joints or MTP joints for short. A subluxation can occur over time in middle-aged runners or dancers who have been exercising on their toes for years. The joint most often involved is the second MTP adjacent to the great toe's bunion joint. Pain is often produces when shifting the toe up and down on an examination and helps differentiate this cause of pain from a neuroma that can have the same symptoms. Subluxation, or looseness, of the joint responds poorly to orthotics and physical therapy. Using a metatarsal pad just proximal to the involved metatarsal heads or taping to support the injured joint may help. A cortizone injection is often effective in eliminating pain and inflammation. When all else fails and the symptoms warrant, surgery is considered to remove inflamed capsule or to realign the joint.

Hammertoes may result in painful calluses or corns over the bony prominence formed from hyperextension of the MTP's and hyperflexion of the proximal toe joints. These may be acquired from years of wearing shoes with a narrow, pointed toe. Treatment starts with using a shoe with a larger toe box and a soft leather upper to accommodate the deformity. Surgery would require a realignment of the offending toes.

Claw toes are similar to hammertoes, but have slightly different alignment problem and are often associated with trauma, spinal cord injury or neurologic problems such a polio. If the deformity is flexible, taping may help relieve symptoms or pads may prevent blistering or callus. Surgery may be required for realigning the malformation.

Hard or soft corns may form over a bony prominence if exposed to mechanical pressure from shoes. A hard corn develops on the outside of the 5th toe from shoe wear and a soft corn develops between the toes at the site of a bony enlargement visible only by x-rays. These can be treated by modifying the shoe; careful shaving of callus and placing a soft pad between the toes may be enough to relieve symptoms. Again, surgical resection of the offending bony prominence may be necessary in resistant cases.

When the first or great toe develops degenerative arthritis from wear and tear or old injuries, bony spurring may occur about the joint, which eventually limits the joint's range of motion. As a certain amount of motion at the big toe is necessary for normal walking, when the bony buildup is enough to severely restrict the upward motion of the joint, pain with walking is the result. In addition to the limited joint range of motion noted on exam, x-rays will demonstrate the bony arthritic spurring. In anti-inflammatory meds, shoe and activity modifications fail; surgery to remove the spurs, replace or fuse the joint may be required.

Another particularly troublesome forefoot problem common in runners and dancers is an inflammation of the sesamoid bones; the small bones just beneath the big toe. They act much like little kneecaps under the toe and are points of attachment of muscle tendons. They disperse the impact forces on the metatarsal head at the big toe and protect the tendon that travels just beneath the toe. They are prone to bursitis or soft- tissue swelling over the sesamoid, bruising of the bone or overuse induced stress fracture, traumatic fracture or degenerative arthritis. Treating with felt padding cut out to relieve pressure on the sesamoid or shoes with a stiff sole along with ice and anti-inflammatory meds and activity restriction may work. In very stubborn cases, surgery to remove one of the two sesamoids is considered.

Lastly, stress fractures of the metatarsal bones, which is the most common location for runners' stress fracture, is usually caused by the proverbial too much, too soon approach to running. Whenever there is forefoot pain and swelling just behind the middle toes, most commonly 2-4, after a period of increased training load, a change to a firmer running surface, or even getting excessive mileage out of a pair of running shoes, a stress fracture must be considered. Cross-training and using a stiff-soled shoe or walking boot will permit healing in 6-8 weeks. A gradual return to running over another several weeks will help prevent recurrence. Surgery is a rare consideration for fractures that simply don't heal correctly.

We've just gone through quite a laundry list of problems that are common in the forefoot of athletes who run. While conservative measures work in the majority of cases, surgery is occasionally required for the best outcome. Prevention with good cushioned, well-fitting shoes, training on softer surfaces, adding mileage gradually and treating pain early and aggressively will reduce the chances of acquiring one of these maladies in the first place. Should pain develop in the forefoot that just doesn't go away with ice, rest and meds, getting a correct diagnosis is often key to directing effective therapy and getting back to one's desired training routine.

Dr. John Robertson practices Sports Medicine at the Nordstrom Tower in Seattle (206) 386-2600.

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