Haglund's deformity, also known as a 'pump bump', is an enlargement of the top surface of the back of the heel bone (calcaneus). This condition is common in women, as the shoe styles often worn by women contribute to the pain. Men can also suffer from this condition as well. The area on the back of the heel bone normally has a gentle slope, behind which the Achilles tendon passes as it attaches to the heel bone slightly further down. In some people, this area can become enlarged, with a rounded prominence of bone forming along the back slope. Genetics play a part in this, as well as high arches and a tight Achilles tendon. When shoes are worn that have a stiff heel backing to them (also known as the heel counter), the pressure from the shoes irritates the bone and the soft tissues that cover the bone, including the Achilles tendon. A pad of tissue called a bursae sits between the Achilles tendon and the heel bone, and this can be irritated. Once the inflammation from all this irritation starts, the heel can become painful to flex upward, and shoe use becomes difficult, especially if the heel counter of the shoe is stiff. Redness and swelling can be seen on the back of the heel, and the skin can even become irritated and peel away. Symptoms can persist for many years.

This condition is fairly easy to diagnose with a simple exam and x-rays, although cases that have more involvement of Achilles tendon inflammation may need an MRI to assess the integrity of the tendon.

Treatment revolves around decreasing the pressure on the heel by changing to shoes with a lower or softer heel counter, as well as stretching of the Achilles tendon to make it more limber. Anti-inflammatory medications and icing are helpful a well, and physical therapy is sometimes used to make the area tissues stronger and more limber. On a temporary basis, the use of a heel lift to increase the Achilles tendon slack and move it off the upper part of the heel bone can help, although this does not provide one with an advantage in the long run. The same can be said about temporary adhesive padding around the irritated area. Cases that are resistant may respond to immobilization in a brace or walking boot. If all this fails to provide relief, surgery may be necessary to either remove the prominent bone and repair the Achilles tendon, or to re-rotate the top surface of the heel bone itself to push the enlarged area further forward.