Seasonal Variation of Achilles Tendon Injury

Abstract

Category: Sports Introduction/Purpose: Achilles tendon ruptures are increasingly common injuries. There are several known risk factors for Achilles tendon rupture, although little is reported on the seasonal variation of the incidence of these injuries. Of the few studies in the literature touching on this question, the results have been varied. We sought to determine if there is any seasonal pattern of Achilles tendon ruptures. Knowledge of such a seasonal pattern could be advantageous for patient education, risk assessment, and ultimately prevention of these injuries. Methods: We queried billing records for CPT codes 27650, 27652, and 27654 as well as ICD diagnosis codes 727.67, 845.09, and S86.01x pertaining to Achilles tendon injury, repair, and reconstruction. Charts were screened and included if the patient suffered an acute Achilles tendon rupture on a known date. Charts were excluded if the patient had a chronic Achilles tear or underwent reconstruction or debridement for tendonitis, Haglunds deformity, tendon laceration, or any other indication aside from acute rupture. Data was analyzed using a chi-squared test for categorical variables, binomial tests for dichotomous variables and Mann-Whitney-U or Welch t-test for continuous variables. Significance was set at p < 0.05. Results: Our search yielded 499 cases with 245 meeting inclusion criteria. Sixty-six percent (66%) of injuries were identified as sports-related while 34% were non-sports related. When stratified by month, significant peaks occurred in April and July (p = .036, .011 respectively) with significantly fewer injuries occurring in October through December (p = 0.049). The highest rate of injury was seen in Spring (p = .015) and the lowest was seen in Fall (p < .001). There was no significant difference between seasons when only the non-sports related injuries were considered. Basketball was the most common sport involved (n=78) accounting for 51% of injuries (p < .001), followed by soccer and tennis. There was no significant variation between seasons in any particular sport. Conclusion: There was significant seasonal variation in the incidence of Achilles tendon ruptures. Both sports and non-sports-related injuries followed a similar pattern, with most injuries occurring during the Spring and Summer and fewer during Fall and Winter. This increase corresponds to the increase in activity in the recreational athlete population in the region which is often preceded by a time of relative inactivity. Our study confirms that the deconditioned athlete is at particularly elevated risk for Achilles tendon rupture during the Spring season when abrupt increases in sporting activity are common. Targeted education and prevention efforts could help mitigate this risk.