The seasonal variation of Achilles tendon ruptures in Vancouver, Canada: a retrospective study

OBJECTIVE: To examine the seasonal distribution of tendon ruptures in a large cohort of patients from Vancouver, Canada. DESIGN: Retrospective chart review. SETTING: Acute Achilles tendon rupture cases that occurred from 1987 to 2010 at an academic hospital in Vancouver, Canada. Information was extracted from an orthopaedic database. PARTICIPANTS: No direct contact was made with the participants. The following information was extracted from the OrthoTrauma database: age, sex, date of injury and season (winter, spring, summer and autumn), date of surgery if date of injury was unknown and type of injury (sport related or non-sport related/unspecified). Only acute Achilles tendon rupture cases were included; chronic cases were excluded along with those that were conservatively managed. PRIMARY AND SECONDARY OUTCOMES: The primary outcome was to determine the seasonal pattern of Achilles tendon rupture. Secondary outcomes, such as differences in gender and mechanism of sport (non-sport vs sport related), were also assessed. RESULTS: There were 543 cases in total; 83% of the cases were men (average age 39.3) and 17% were women (average age 37.3). In total, 76% of cases were specified as sport related. The distribution of injuries varied significantly across seasons (χ(2), p<0.05), with significantly more cases occurring in spring. The increase in the number of cases in spring was due to sport-related injuries, whereas non-sport-related cases were distributed evenly throughout the year. CONCLUSIONS: The seasonality of sport-related Achilles tendon ruptures should be considered when developing preventive strategies and when timing their delivery.