@article { , title = {Risk Factors for Knee Osteoarthritis in Retired Professional Footballers: A Cross-Sectional Study}, abstract = {Objective: To determine risk factors for three knee osteoarthritis (KOA) outcomes, knee pain (KP), radiographic KOA (RKOA) and total knee replacement (TKR), in professional footballers. Design: This was a cross-sectional study involving a postal questionnaire, followed by radiographic assessment in a sub-cohort of responders. Settings and Participants: 4775 questionnaires were sent to retired professional footballers, who had played in the English football league, and 1207 responded. Of these, 470 underwent knee radiographs. Assessment of Risk Factors: Potential factors include age, BMI, knee alignment, a history of football-related knee injury, and training hours (during career) were collected via the questionnaire. Main Outcome Measures: KOA outcomes were current KP (pain for most days of the previous month), TKR (self-reported) and RKOA (observed via radiographs). Results: Football-related injury was the strongest risk factor for KP [aOR 4.22, 95\%CI 3.26-5.48], RKOA [aOR 2.88, 95\%CI 1.81-4.59] and TKR [aOR 4.83, 95\%CI 2.87-8.13]. Footballers had a 7\% increased risk of RKOA for every 1000 hours trained. While age and gout were associated with all three KOA outcomes, BMI, nodal OA, a family history of OA, knee malalignment and 2D:4D ratio were associated with one or another of these three KOA outcomes. Conclusion: This study is the first to examine KOA risk factors in retired professional footballers. The study has identified several risk factors, both specific (for example, knee injury and training dose), and non-specific (for example, age and gout) to footballers. This may be used to develop prevention strategies to reduce the risk of KOA in professional footballers following retirement.}, doi = {10.1097/JSM.0000000000000742}, eissn = {1536-3724}, issn = {1050-642X}, issue = {3}, journal = {Clinical Journal of Sport Medicine}, pages = {281-288}, publicationstatus = {Published}, publisher = {Lippincott, Williams \& Wilkins}, url = {https://nottingham-repository.worktribe.com/output/1595231}, volume = {31}, keyword = {Medical Science, Arthritis Research UK Centre for Sport Exercise and Osteoarthritis, RPA - Health Humanities, football, knee osteoarthritis, knee replacement, knee pain, risk factors}, year = {2021}, author = {Parekh, Sanjay M. and Fernandes, Gwen S. and Moses, Jonathan P. and Fuller, Colin W. and Scammell, Brigitte E. and Batt, Mark E. and Zhang, Weiya and Doherty, Michael} }