Age is a risk factor for contralateral tendon rupture in patients with acute Achilles tendon rupture

Purpose: Rupture of the contralateral Achilles tendon following Achilles tendon rupture can lead to devastating outcomes. However, despite the clinical importance, the risk factors and incidence of contralateral Achilles tendon rupture have not been well studied. This study aimed to determine the incidence of contralateral tendon rupture after Achilles tendon rupture and to identify associated patient characteristics. Methods: Medical records for 226 consecutive patients with Achilles tendon rupture were retrospectively reviewed. The occurrence of contralateral Achilles tendon rupture and patient characteristics were determined through review of medical records and telephone surveys. Results: The cumulative incidences of contralateral Achilles tendon rupture at 1, 3, 5, and 7 years after Achilles tendon rupture were 0.4%, 1.8%, 3.4%, and 5.1%, respectively. The only statistically significant risk factor was age between 30 and 39 years at the time of initial Achilles tendon rupture (hazard ratio = 4.9). Conclusions: Patients who sustain Achilles tendon rupture in their 30 s have significantly increased risk for contralateral tendon rupture. Level of evidence: III.