Risk factors for patellar tendinopathy in volleyball and basketball players: A survey-based prospective cohort study.

Patellar tendinopathy (PT) is a common overuse injury of the patellar tendon in jumping athletes. In a recent large cross-sectional study from 2008 several factors were identified that may be associated with the etiology of PT. However, because of the study design no conclusions could be drawn about causal relations. The primary aim of the current study is to investigate whether the factors identified in the previous 2008 study can also be prospectively recognized as predictors of symptomatic PT in 2011. Nine hundred twenty-six Dutch elite and non-elite basketball and volleyball players from the previous study were invited again to complete an online survey about knee complaints and risk factors for PT in 2011. The logistic regression included 385 athletes of which 51 (13%) developed PT since 2008. Male gender [odds ratio (OR) 2.0, 95% confidence interval (CI) 1.1-3.5] was found to be a risk factor for developing PT. No sports-related variables could be identified to increase the risk of developing PT, but some evidence was found for performing heavy physically demanding work, like being a nurse or a physical education teacher (OR 2.3, 95% CI 0.9-6.3). These findings indicate that, when considering preventive measures, it is important to take into account the total tendon load.