Objective: In Achilles tendon injuries, it is suggested that a pathological continuum might be evident from the healthy Achilles tendon to Achilles tendinopathy to Achilles tendon rupture. As such, risk factors for both tendinopathy and rupture should be the same.
Hypothesis: Hereditary and medical risk factors for Achilles tendinopathy and Achilles tendon rupture are the same to a similar extent in a matched pair analysis.
Design: Matched pair study; level of evidence: 3.
Setting: Recreational sportsmen as well as athletes on national level.
Patients: 566 questionnaires were analysed. 310 subjects were allocated to 3 groups (A, B, C) after matching the pairs for age, weight, height and gender: (A) healthy Achilles tendons (n = 89, age 39 ± 11 years, BMI 25.1 ± 3.9, females 36%), (B) chronic Achilles tendinopathy (n = 161, age 41 ± 11 years, BMI 24.4 ± 3.7, females 34%), (C) acute Achilles tendon rupture (n = 60, age 40 ± 9 years, BMI 25.2 ± 3.2, females 27%).
Results: We found a positive family history of Achilles tendinopathy as a risk factor for Achilles tendinopathy (OR: 4.8, 95% CI: 1.1-21.4; p = 0.023), but not for Achilles tendon rupture (OR: 4.0, 95% CI 0.7-21.1, p = 0.118). Smoking and cardiac diseases had a lower incidence in Achilles tendinopathy than in healthy subjects (both p = 0.001), while cardiovascular medication did not change the risk profile.
Conclusion: Identifying risk factors associated with Achilles tendon disorders has a high clinical relevance regarding the development and implementation of prevention strategies and programs. This cross-sectional study identified a positive family history as a significant solitary risk factor for Achilles tendinopathy, increasing the risk fivefold. However, in this matched pair analysis excluding age, weight, height and gender as risk factors no further factor necessarily increases the risk for either Achilles tendinopathy or Achilles tendon rupture.