Professional football (soccer) is a demanding contact sport with a high incidence of injuries; 17% of these injuries are associated with players’ knees. According to the results of a recent study, men who retired from playing professional football are more likely to experience knee pain, have osteoarthritis (OA), and require total knee replacement (TKR) surgery than men in the general population (Fernandes GS, et al. Br J Sports Med. 2017 Nov 3. Epub ahead of print).
Based on their hypothesis that knee OA and knee arthroplasty are more common in former football players than in the general population, Gwen Sascha Fernandes, PhD, Division of Orthopaedics and Dermatology, School of Medicine, University of Nottingham, Nottingham City Hospital, United Kingdom, and colleagues conducted a study to compare the prevalence of, and risk factors for, knee OA in ex-footballers with those in nonplayers.
To recruit participants for this large-scale, cross-sectional study, which was funded by Arthritis Research UK and supported by FIFA (Fédération Internationale de Football Association)’s Medical and Research Centre, the Professional Footballers’ Association, and SPIRE Healthcare Group, Dr Fernandes and colleagues mailed questionnaires to 4775 retired male professional football players, as well as to 40,000 men and women from the Knee Pain and Related Health in the Community Study.
A screening question in the surveys asked recipients whether they had knee pain for the majority of days during the past month. Additional information gathered from the questionnaires included medical history (including previous knee surgeries), reputed risk factors associated with knee OA, comorbidities, prescribed medications, occupations, current body pain, 2D:4D ratio (ie, the ratio of the length of the index finger to that of the ring finger, which has been linked to OA), and knee alignment (depicted through validated line drawings).
To participate in the study, individuals who had not undergone TKR surgery had to consent to knee radiographs. A total of 1207 retired male professional football players (average age, 59 years) and 4085 men from the general population in the United Kingdom (average age, 62.9 years) returned the questionnaires, and were enrolled in the study.
After analyzing the collected data, Dr Fernandes and colleagues found that the retired football players were more likely to experience knee pain, have knee OA, and require TKR surgery than their counterparts.
“The prevalence of all knee outcomes was almost two to three times higher in ex-footballers even after adjustment for known risk factors including significant knee injury,” Dr Fernandes and colleagues stated, adding that “repetitive micro trauma associated with playing football” was likely an important contributing factor to the difference in outcomes among the study groups.
The occurrence of self-reported knee pain was also greater in the group of ex-footballers than in the general population, regardless of age, and was, in fact, more frequently reported in younger age-groups. In addition, ex-footballers were found to have more nodal OA, 2D:4D pattern 3, overall body pain, and knee misalignment than men in the general population. Interestingly, the prevalence of comorbidities such as cancer and diabetes was higher in the general population than in the group of ex-footballers.
“These findings have important consequences for football associations/unions and stakeholders for whom the health of retired and current professional footballers is paramount,” Dr Fernandes and colleagues concluded.