Haglund’s deformity is a common condition affecting the heel. It is sometimes referred to as “pump bump” due to its frequent association with stiff footwear. This bony enlargement on the back of the heel causes irritation, leading to pain and swelling in the surrounding soft tissues. The condition involves a complex interaction between the individual’s foot structure and external forces.
The Anatomy of Haglund’s Deformity
The physical cause of this condition is an abnormality in the structure of the calcaneus, or heel bone. Haglund’s deformity involves a bony overgrowth, known as a posterior superior calcaneal prominence or exostosis, on the upper back part of the heel. This bony spur projects outward, altering the normal contour.
The enlargement sits directly beneath the Achilles tendon insertion and adjacent to the retrocalcaneal bursa, a fluid-filled sac that cushions the area. When the bony prominence is present, it reduces the space between the tendon and the heel bone. Movement causes the tendon to rub against the spur, irritating the bursa and leading to inflammation (bursitis). Repeated pressure can also cause inflammation of the Achilles tendon itself, known as Achilles tendinitis.
Biomechanical Risk Factors
A person’s individual foot structure and movement patterns significantly increase the risk of developing symptoms. These biomechanical factors determine how much pressure and friction are placed on the posterior heel. A common predisposing factor is the presence of a high arch, known medically as pes cavus.
A high arch causes the heel bone to tilt backward and upward when bearing weight. This effectively shortens the space between the heel bone and the Achilles tendon insertion. This backward tilt forces the tendon and the retrocalcaneal bursa to press more firmly against the bony prominence, accelerating irritation and inflammation.
A genetically tight or short Achilles tendon is another structural factor. A tight tendon pulls more tautly against its insertion point, increasing mechanical compression in the area. This increased tension minimizes the ability of the tendon to glide smoothly over the exostosis, leading to greater friction and irritation of the bursa.
Specific gait mechanics also play a role, particularly a tendency to walk on the outside edge of the heel, known as supination. This outward rolling motion places disproportionate stress on the outer portion of the heel. The altered alignment exacerbates the rubbing of the Achilles tendon against the bony prominence, contributing to pain and swelling.
The Influence of Footwear
While intrinsic foot structure creates the predisposition, external factors like footwear are often the direct triggers that accelerate the condition. The nickname “pump bump” highlights the strong association between the deformity and certain shoe styles. Any shoe with a rigid, unforgiving back, known as a heel counter, can cause chronic irritation.
The stiff material of the heel counter continuously rubs against the bony prominence with every step, causing mechanical friction. This repetitive rubbing leads to skin irritation, redness, and inflammation of the underlying soft tissues. Problematic footwear includes:
- Women’s high heels
- Men’s dress shoes
- Ice skates
- Work boots
Tight-fitting shoes or those that lack adequate cushioning also contribute by increasing pressure on the posterior heel. The upper edge of the shoe presses directly into the bony bump, exacerbating the compression of the retrocalcaneal bursa. Wearing these types of shoes can trigger the painful inflammatory response in individuals with a pre-existing bony prominence.