Overuse injuries of the Achilles tendon can be divided into insertional and non-insertional problems. Since there is no evidence available for inflammation in patients with “tendinitis” the term tendinosis has been proposed (Puddu et al. 1976). In 1998, Maffuli proposed to use the term tendinopathy: clinical definition, characterized by a combination of pain, swelling, and impaired performance of the tendon (Maffuli et al. 1998). When the pain is located at the posterosuperior calcaneal prominence, this entity has been called Haglund’s syndrome (Haglund 1928). Originally Haglund described a condition of a painful hindfoot caused by an enlarged posterosuperior calcaneal border in combination with wearing of rigid low-back shoes (Van Dijk 2006). Today in Haglund’s disease, we describe a clinical situation of pain and tenderness at the posterolateral aspect of the calcaneus where a calcaneal prominence can be palpated. This entity is also known as “pump bump.” A distinction between Haglund’s disease and other pathologic conditions such as a superficial Achilles bursitis must be made. It must be differentiated from Haglund’s syndrome. This syndrome involves a painful swelling of an inflamed retrocalcaneal bursa sometimes combined with insertional tendinopathy of the Achilles tendon. The syndrome is caused by repetitive impingement between the ventral aspect of the Achilles tendon and the posterosuperior calcaneal prominence. Patients typically have pain after a period of rest, when starting walking. Operative treatment consists of removal of the inflamed bursa and resection of the bony prominence. A distinction should be made with other pathologies in this region.

We have proposed a terminology which comprises the combination of anatomical location, symptoms, clinical findings, and pathological changes for each entity (Van Dijk et al. 2011; Wiegerinck et al. 2012b). The terminology is shown in the insert. Achilles tendinopathy and paratendinopathy often coexist. Retrocalcaneal bursitis is often seen in combination with insertional tendinopathy. Other combinations are possible but occur less frequently.

The retrocalcaneal bursa is situated in the retrocalcaneal recess between the anterior aspect of the Achilles tendon and the posterosuperior part of the calcaneus (Fig. 21.5).

Kager’s fat pad, also known as the pre-Achilles fat pad, is a mass of adipose tissue occupying the Kager’s triangle. Normally this fat pad, as seen on a lateral standing radiograph of the ankle, is a triangular radiolucency with sharp, gently curving borders. The anterior border is the posterior aspect of the flexor hallucis longus muscle and tendon, the posterior border is the Achilles tendon, and the distal border is the superior surface of the calcaneus.

Retrocalcaneal bursitis is caused by repetitive compression of the retrocalcaneal bursa between the anterior aspect of the Achilles tendon and the posterosuperior aspect of the calcaneus. It occurs most often at the end of the second or the third decade, mainly in females, and is often bilateral. However, it may occur in both sexes and at any age.

With dorsiflexion of the ankle, the anterior part of the tendon impinges against the posterosuperior rim of the calcaneus. This repetitive motion can lead to retrocalcaneal bursitis. A hindfoot varus and pes cavus are both predisposing factors for heel pain. In the cavus foot, the calcaneus is not only in varus malalignment, but it is also more vertical, which results in a more prominent projection posteriorly.