Metatarsalgia is often referred to as a symptom rather than a disease. It presents as pain in the forefoot associated with increased stress over the metatarsal head region (the area from the base of the toes to the middle of the foot, i.e. the front third of the foot).
Metatarsalgia is a common overuse condition, i.e. a history of gradual onset is more common than sudden or acute presentation. Chronic symptoms may appear over a period of six months.
Causes of Metatarsalgia
Athletes participating in high impact sports, including running or jumping are at risk. Their bodyweight is transferred onto the forefoot during the midstance and pushoff phases of walking and running. The first and second metatarsal heads receive the greatest amount of this energy transfer.
The vertical forces that act on the foot can be up to 3 times the bodyweight of that person. This is due to a combination of momentum and weight during walking or running. Runners spend most of the time weighted over the forefoot while running.
People with high arched feet which absorb less shock are more prone to metatarsalgia. Basically the metatarsals cannot get out of the way when stress is being placed on this area of the foot due to the increased rigidity of the high arched foot.
Forefoot deformities such as hammer or clawed toes increase the risk of developing metatarsalgia. Due to the deformity, the metatarsal arch is closer to the ground than it should be and therefore absorbs excessive pressure.
Corns or calluses usually develop under the metatarsal heads or under the tips of the toes. This is the body’s normal response to pressure. Extra skin builds up on the areas of pressure to try and protect the area. Initially this response is a help, but if it becomes too thick then it adds even more pressure on the nerves and vessels of the area, causing more pain.
Morton’s neuroma (interdigital neuroma) produces symptoms of metatarsalgia due to irritation of the digital nerve located in the web space between the metatarsal heads. Patients with Morton’s neuroma complain of numbness in the toes, particularly the 2nd and 3rd toes.
Patients with a Morton toe (2nd toe is longer than the big toe) have a short 1st metatarsal bone, resulting in the normal balance of the forefoot being disturbed. Abnormal subtalar joint pronation occurs and this collapse causes increased pressure on the 2nd metatarsal.
In women wearing high-heeled shoes, the centre of gravity shifts forward over the front of the foot, placing more pressure under the metatarsals. The added height of a high-heeled shoe also allows the muscles under the foot to shorten, which over a period of time can alter the shape of the foot permanently.
Arthritis and stress fractures also produce similar symptoms to metatarsalgia.
Treatment of metatarsalgia
Prevention is better than cure. It is important to assess your footwear to check that you are using the correct shoe for the application. Shoes should have sufficient cushioning in the forefoot area to absorb shock efficiently.
In people with a known tendency to pronate, anti-pronation sports shoes should be used. Shoes should also have enough breadth across the toes so as not to cramp the toes together. Avoid wearing high-heeled shoes for long periods of time, or better still, avoid them all together!
Treatment involves stretching the affected muscles and the placing of a cushioning metatarsal support in the shoes in order to achieve better weight distribution.
(Written by Dallas Fell and Chris Delpierre, registered podiatrists with the H.P.C.S.A)
South African Podiatry Association (SAPA)