Abstract
Introduction
Numerous risk factors have been identified for patellar tendinopathy (PT), often in small population studies. The aim was to use an online questionnaire internationally to generate a large database and identify significant risk factors.
Materials and Methods
Subjects were recruited from England, Spain and Italy with the questionnaire available in all three languages, with the questionnaire previously having been validated by Morton et al. (2014) as to be suitable for self-administration. The questionnaire can be viewed at: http://patellartendinopathyquestionnaire.blogspot.co.uk/ (English), http://tendinopatiarotuliana.blogspot.co.uk/ (Spanish) and http://tendinopatiarotulea.blogspot.co.uk/ (Italian). All data was anonymised and password protected. 825 data sets were collected with 23.4% having clinically diagnosed PT.
Results
Eight risk factors were included in the analysis based on a purposeful selection procedure: gender, hours of training, hamstring flexibility, previous patellar tendon rupture, previous knee injury, current/previous back pain, family history and age. To be female was found to be positively associated with PT, suggesting being female is protective (odds ratio (OR) = 0.70, 95% CI: 0.49–1.00, p=0.05). As hours of training increased the association with PT became stronger so that training >20 hours a week had a very significant OR of 8.94 (95%CI: 4.68–17.08, p<0.05), the most significant OR calculated. There was an association between a previous knee injury and PT (OR=2.10, 95% CI: 1.45–3.04, p<0.05) and having self-reported flexible hamstrings suggested some protection from PT (OR=0.61, 95% CI0.38–0.97, p=0.04). There was a trend towards association for back pain (OR=1.45, 95% CI: 0.99–2.14, p=0.06) and a family history of tendon problems (OR=1.51, 95% CI: 0.96–2.37, p=0.08).
Discussion
Risk factors have been identified that are potentially modifiable in order to inform prevention and rehabilitation programmes; future research is required to establish causal relationships. Certain risk factors require investigation as they are not currently recognised in the literature.
