Metatarsalgia describes a wide group of conditions that cause general pain to the ball of the foot. The word metatarsalgia means pain in the metatarsals, which are long bones located along the length of the foot. These long bones begin in the middle of the foot, and end at the bases of the toes. Each bone corresponds with a toe, so there are five total. Any pain that is felt in the ball of the foot, where these bones meet the toes, is often grouped together into the general condition of metatarsalgia.
Metatarsalgia can be caused by numerous separate conditions, but nearly all of them have one thing in common: the foot structure. Simply put, those with flat feet and those with high arches have a much higher chance of developing metatarsalgia than those with a more normal foot structure. Flat feet and high arches lead to increased pressure and strain to the ball of the foot. Flat feet over-stretch, leading to strain under the ball of the foot. High arched feet are much more rigid, with increased pressure to the ball of the foot the result of an inability to relax the foot structure sufficiently. Eventually, the simple daily act of walking and standing on a flat or high arched foot will lead to pain under where the metatarsals meet the toes under the ball of the foot. This area contains several structures that can become inflamed and painful as a result of this increased strain and pressure. The area where the metatarsal meet the toe is actually a joint, and the tissue that covers the joint and keeps it in place can become inflamed. This condition is called capsulitis, named after inflammation of the joint 'capsule'. The joint itself can also become arthritic and inflamed due to long term wear and tear. Sometimes, the metatarsal bone is abnormally angled downward due to genetics or backwards pressure from the toe, which can lead to abnormal joint stress. Next to each joint is a nerve that can often become inflamed, and can contribute to metatarsalgia. If one is older or has certain diseases involving collagen or skin, the fat pad underneath the metatarsals can be thin or displaced away from the bones it is padding. This can result in bone bruising due to abnormal pressure. The skin overlying this area on the bottom of the foot can become callused, further causing pain and discomfort. Finally, certain poorly fitting shoes can actually lead to more pressure to the ball of the foot, worsening a foot that is at risk for metatarsalgia.
Treatment for metatarsalgia revolves around addressing the specific conditions that are causing the pain. Some of this treatment however is universal, and applies to multiple conditions. Techniques like reducing the inflammation with icing and medication, as well as providing further foot support for the underlying foot structure problem are usually effective. This support comes in the form of better shoes for one's specific foot structure, as well as orthotic inserts to control a flat foot or cushion a high arch. Depending on the underlying condition, other treatment may be needed, including injections, immobilization of the foot, or surgery. There is not one specific answer for this group of conditions, and multiple types of treatment is usually necessary.