Does playing football really increase the risk of knee osteoarthritis? A Systematic Review and Meta-analysis.

OBJECTIVE: To evaluate the relationship between football (soccer) participation and tibiofemoral knee osteoarthritis (OA), considering the influence of competitive level and previous knee injuries. DESIGN: Aetiology systematic review with meta-analysis. LITERATURE SEARCH: PubMed, Embase, AMED and Cochrane were searched for relevant publications. STUDY SELECTION CRITERIA: Studies of football players that included a control group consisting of mainly sedentary non-football players, and the relationship of knee OA, were considered. The studies had to report radiographically-verified knee OA and specify football activity. DATA SYNTHESIS: Eleven studies, involving 1,805 football players and 4,022 control individuals were included. Subgroups consisting of data regarding level of play and previous injuries were also synthesized. RESULTS: The overall prevalence of knee OA among football players was increased among professional and recreational players, compared with controls. When knee injuries were excluded, there was no difference in knee OA between football players and controls (OR 1.25; [95% CI 0.61-2.54]). Football players with a previous knee injury had a greater risk of knee OA when compared with football players with no history of previous knee injury (OR 4.16; [95% CI 1.97-8.77]). CONCLUSION: Football players were at increased risk of knee OA. However, after excluding participants with a history of previous knee injury, there were no differences in knee OA between football players and controls. Previous knee injury was important for developing knee OA. Playing football, in the absence of major knee injuries, did not increase the risk of knee OA.