Pain under the ball of the foot is known medically as "metatarsalgia" and has a variety of causes. The ball of the foot is made up of the five metatarsophalangeal joints (photo), which are the joints where the toes flex and push off the ground. The most common cause of metatarsalgia is abnormal foot structure or function, which leads to excess ground pressure at the ball of the foot. It often occurs with a high arch foot or with contracted toes, also known as hammer toes or claw toes.
Any foot condition that results in excess pressure on the ball of the foot can lead to metatarsalgia. It is also common to have calluses on the ball of the foot, which occur in response to stress but end up contributing to the pain and discomfort. The most common causes of metatarsalgia are:
- High Arched Foot (Pes Cavus)- A high arch foot does not distribute pressure from walking very well, resulting in excess pressure at the heel and ball of the foot. It is very common for a person with high arches to experience pain in the the ball of the foot, and excess shoe and sock wear in this area. People with high arches often feel discomfort when walking barefoot on hard surfaces and require shoes with thick, supportive soles. If you have high arches, chances are your Achilles tendon is also tight, which can contribute to metatarsalgia. A tight Achilles tendon is a common problem with other foot types as well, even flat feet. Daily ankle stretches targeting the Achilles tendon are helpful at reducing metatarsalgia.
Diseases that cause neuropathy, or nerve damage, also can lead to foot changes that result in high arches with painful calluses and metatarsalgia. A common example is diabetic neuropathy.
- Loss of Plantar Fat Pad- The plantar surface, or sole of the foot, has a thick layer of connective tissue meant to protect the underlying bones from excess pressure. As we age, this fat pad gets thinner -- making the sole of the foot more sensitive to ground pressure as we walk. Gel insoles, arch supports, or custom orthotics for shoes can be used to offset some of the pressure and provide comfort. Newer procedures to address fat pad loss are emerging, and include the use of injectable dermal fillers or autologous (meaning the patient's own) fat which are injected into the skin to provide extra cushioning.
- Trauma- Chronic trauma to the metatarsal heads (rounded ends of the metatarsal bones) can lead to bursitis, bone bruising, arthritis, or inflammation of other surrounding tissues. Acute trauma such as a fracture of a metatarsal bone, sesamoid bone fracture or torn big toe ligaments (also known as turf toe) can cause metatarsalgia. An X-ray or MRI is used to diagnose these injuries and they require immobilization and occasionally surgery as treatment.
- Other Causes of Metatarsalgia or Conditions that Have Similar Symptoms-
- Neuroma- usually causes pain between or below the third and fourth toes and is caused by nerve irritation and thickening
- Abnormal Metatarsal Length- metatarsal bone is either too short or too long
- Painful Sesamoid Bones- These two small bones sit under the first metatarsal bone near the big toe joint and become painful, either from fractures or inflammation of the surrounding soft tissue. Click to See Image of the Sesamoid Bones.
- Hallux Limitus- restricted range of motion at the big toe joint (first metatarsophalangeal joint) can cause increased pressure at other metatarsal bones
A podiatric evaluation for pain in the ball of the foot may involve X-rays to identify fractures or other bone and joint abnormalities. MRI or other imaging studies may be prescribed to assess the soft tissues for causes of pain such as ligament tears. EMG (electromyogram) and nerve conduction studies may be prescribed to identify a neuroma, pinched nerve, or other forms of neuropathy.
Treatment will vary depending on the cause but in many cases may involve:
- Cortisone injections or anti-inflammatory medicines to relieve pain
- Shaving down (debriding) calluses to relieve pain
- Custom-made or OTC orthotics
- Padding or special modifications to arch supports or orthotics to relieve pressure under the ball of the foot
- Surgery to correct any bone abnormalities
- Surgery or alcohol injections to treat a neuroma
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