Metatarsalgia is a condition that presents with pain to the front of the foot (ball or forefoot) that usually results from activity and/or faulty foot mechanics.
A review of anatomy is necessary to explain this common condition. The toe bones (phalanges) two in the big toe, three in toes two through five, and the metatarsal bones (long bones in ball of foot), meet at the ball of the forefoot where the toes flex up and down to form the metatarsal- phalangeal joints. These joints are numbered one to five from big to little toe. When standing the metatarsals have a downward slope and we stand on the front part of the bones called the heads. All five metatarsal heads should bear an equal amount of weight, one-fifth or 20% of the forefoot load to each metatarsal head. The space between each metatarsal is called the intermetatarsal space. Among the anatomy that resides in these spaces are structures called bursas. A bursa is a fluid filled cavity or balloon type structure that acts to provide cushion and shock absorption.
The intermetatarsal bursa are found between metatarsal heads two though five and are small, about the size of a little grape. As we walk or run a tremendous amount of weight or load is presented to the forefoot. With proper foot function and anatomy the forefoot load is absorbed and pain free ambulation is achieved. Improper function or faulty anatomy can result in activity induced pain to the ball of the foot known as metatarsalgia. This term is non-specific. It does not define the reason why a person is experiencing pain to the forefoot. A thorough history and physical exam along with possible x-ray studies is necessary to determine the cause of a persons metatarsalgia symptoms.
Anatomical variations can lead to metatarsalgia symptoms. A person may have a metatarsal that is longer or shorter than the adjacent bones. A metartarsal bone can be positioned too high or low in comparison to the other metatarsals. With these variations all five metatarsal heads may not be on the ground equally, thus not bearing their 20% of the forefoot weight load. Anatomy of a metatarsal can be altered by trauma, such as a break/fracture, thus changing the position and function of that bone. This may result in more or less pressure to the effected bone, or the adjacent bones. Arthritis (degenerative joint disease) can lead to painful function at the metatarsal- phalangeal joints. A tight heal cord/Achilles tendon (a condition called equines) can lead to increased pressure to the forefoot. A high or low arch can lead to altered pressure across the metatarsal heads. Neuromuscular conditions can alter the way a person walks/runs resulting in uneven weight distribution to the forefoot.
Improper or faulty foot mechanics may lead to metatarsalgia symptoms. If there is uneven weight distribution across the ball of the foot, swelling to the bursa between the metatarsal heads may occur. Many people describe this as if their socks are bunching up under the ball of the foot or they are walking on a lump. If a bursa remains swollen it can pinch the adjacent intermetatarsal nerve (which is a nerve headed towards the tips of the toes to give sensation around the nail) and lead to a neuroma. A neuroma is a swollen nerve in the intermetarsal space that can present with sharp, electrical type symptoms that can radiate towards the toes becoming increasingly debilitating.
Once the cause of an individuals metatarsalgia is identified a treatment protocol can be established. Most treatment is non-surgical. If faulty foot function is contributing, adding an orthotic (shoe inlay) along with the use of proper supportive shoes may be very helpful. Many different types of orthotics are available depending on the nature of the problem. Self directed or formal physical therapy can help with tight or weak muscles and tendons, muscle group imbalance, and inflammation (swelling) involving soft tissue structures (bursa), joints, and irritated nerves. Oral (medication) and injectable anti-inflammatory medication can have a dramatic effect on metatarsalgia symptoms. Many times a combination of conservative treatments are necessary to achieve pain free ambulation. Surgical treatments are reserved for conditions requiring that something needs to be fixed, such as a fractured metatarsal bone that has not healed or healed improperly, or a metatarsal bone that is dramatically out of position. A chronically swollen, painful neuroma that has been unresponsive to conservative care may respond well to surgical options also.
In most cases once the diagnosis of metatarsalgia is made and the likely cause indentified, non-surgical treatment protocols alleviate most patients symptoms.