Letters to the Editor

Dear Sir,

We read with interest the article by Kang et al. ¹ investigating the relationship between the insertional Achilles tendinopathy and Haglund's deformity. The authors evaluated the prevalence of Haglund's deformity in patients with and without insertional Achilles tendinopathy, showing that, in their cohort, Haglund's deformity is not indicative of insertional tendinopathy. For this reason, they questioned the need to routinely resect the posterosuperior corner of the calcaneum during surgery for the management of insertional Achilles tendinopathy. We respectfully point out that this study used an antiquated and confusing terminology.

First of all, the term “tendinitis” instead of “tendinopathy” was used. We advocated the use of the term “tendinopathy” to indicate the clinical syndrome of pain, swelling (diffuse or localized), and impaired performance arising from overuse in and around tendons. ⁵ Descriptive terms, including “tendinosis” (a degenerative pathology with a lack of inflammatory change) and “tendonitis” or “tendinitis” (implying an inflammatory process) should be used only after histologic analysis. Tendinopathy is essentially a failed healing response, and, already in 1998, we suggested that the term “insertional tendinopathy” should be used. ⁴

More recently, we proposed that terms such as Haglund's disease, Haglund's syndrome, and Haglund's deformity should not be used, and we also formulated specific definitions for Achilles tendon disorders on the basis of anatomic location, symptoms, clinical findings, and histopathology. ⁸ A posterosuperior calcaneal prominence is a finding that can be present in both retrocalcaneal bursitis and insertional Achilles tendinopathy. The former consists of inflammation of the bursa between the insertion of the Achilles tendon and the posterosuperior aspect of the calcaneus, leading to a painful soft tissue swelling at the level of the posterosuperior calcaneus. The latter is an overuse condition affecting the insertion of the Achilles tendon on the calcaneus, usually presenting bone spurs in the tendon at the insertion site. The tendon insertion is painful at the posterior aspect of the calcaneum, and the bony spur can be palpable.

Finally, the authors pointed out that the majority of patients with insertional Achilles tendinopathy also have calcifications within the tendon. However, we would clarify that insertional tendinopathy and calcific tendinopathy should be considered different conditions. Indeed, the calcific insertional tendinopathy is characterized by the ossification of enthesial fibrocartilage as shown by the findings at radiography, including ossification or bone spur at the insertion of the tendon. ⁸

Histopathologically, the portion of tendon adjacent to the calcified lesions shows features of chondroid metaplasia. ⁶ In this area, tenocytes are round-shaped with a prominent nucleus like chondrocytes. Moreover, the composition of the extracellular matrix is changed, showing reduced type I collagen and increased type II collagen content. These metaplastic changes may occur as an adaptive response to abnormal compressive forces on the enthesis instead of tensile load. ⁹ Indeed, the most represented collagen in normal tendons is type I, resistant to tensile forces, while type II is suited to resist compression. ⁷

In conclusion, we advocate the use of appropriate definitions on the basis of the anatomic location, symptoms, clinical findings, and histopathology to avoid confusing terminology. Among the Achilles tendon disorders, five different conditions should be distinguished: midportion Achilles tendinopathy, Achilles paratendinopathy, insertional Achilles tendinopathy, retrocalcaneal bursitis, and superficial calcaneal bursitis. ⁸ In some patients with insertional Achilles tendinopathy, a calcific component may be present. Finally, in patients with symptomatic insertional Achilles tendinopathy who fail an appropriate conservative management, ² surgery including exploration of the insertion, excision of the subcutaneous and retrocalcaneal bursa, excision of the tendinopathic area, and osteotomy of the posterosuperior corner of the calcaneum to remove the impingement that may contribute to the symptoms should be considered. ³ However we are sure that, for the correct indications, other procedures can be equally successful.