Background: the origin of chronic Achilles tendinopathy (AT) is currently unclear and epidemiological factors, such as ethnicity, may be associated.

Methods: intraoperative findings from the treatment of 865 Finnish and 156 Italian athletic patients with chronic Achilles tendon related pain were evaluated, retrospectively. The mean age was 34 years (range, 18 to 65 years) in the Finnish and 29 years (range, 17-63 years) in the Italian patients. In total, 786 patients were males and 226 females of which 84 and 87% Finnish, respectively. Data were collected, retrospectively from patient records. The differences in the frequencies of operative findings were assessed for statistical significance.

Results: retrocalcaneal bursitis, partial tear and chronic paratenonitis were the most prevalent findings in patients with chronic AT undergoing surgery. Tendinosis and chronic paratenonitis were significantly (p=0.011) more common in Finnish athletes. Italian patients exhibited significantly (p<0.001) more insertional calcific tendinopathy (heel spurs) and prominent posterosuperior calcaneal corners (Haglund's heel).

Conclusion: ethnicity appears to be associated with specific characteristics of overuse-related Achilles tendon pathology. This is an issue that should be considered in the planning of genetic research on AT.