ReviewKnee and ankle osteoarthritis in former elite soccer players: A systematic review of the recent literature
Introduction
Because they are exposed to high intensity and prolonged sports activity as a part of their work, elite athletes are particularly vulnerable to sports related health risks. The most obvious risk of sports activity, which has been shown to occur more often during competition and at higher levels of participation, is the development of musculoskeletal injuries.1, 2, 3 According to several studies, soccer has one of the highest injury rates among sports.4 The most common injury types described in elite soccer are muscle strains, ligament sprains and contusions, particularly involving the thigh, knee and ankle.5, 6, 7, 8 Less common risks of exercise include sudden cardiovascular death, acute myocardial infarction and arrhythmia.1, 9, 10 Additionally, continuous excessive training in combination with insufficient time to recover has been suggested to result in so-called ‘overtraining syndrome’, which manifests in overuse injuries, poorer performance, mood disturbances and immune system deficits.11
A significant long-term effect of vigorous physical activity is the development of osteoarthritis.12 Osteoarthritis (OA), or ‘degenerative joint disease’, is the most common form of arthritis and results in irreversible pathologic changes in affected joints.13 The main symptoms are joint pain, stiffness, reduced function, instability, deformity, swelling and crepitus.14 The disease has been shown to have major consequences. In high-income countries it is the 10th leading cause of disability and is responsible for 2.5% of total disability adjusted life years (DALYs).15 In addition, compared to age- and sex-matched controls, patients with OA are more likely to suffer from comorbid conditions, both musculoskeletal and non-musculoskeletal, with an odds ratio (OR) of 2.35.16 Risk factors for developing OA are well known and can be divided into two categories: systemic and local factors.17 Systemic risk factors are thought to make the joint vulnerable to local factors and are thereby associated with the development of OA. They include age, gender, hormonal status and genetics. Local risk factors cause abnormal biochemical loading on joints and include obesity, occupational activities (squatting, kneeling, lifting), joint injury and certain types of sports participation.17, 18 High-intensity and prolonged sports activity, especially at an elite level, have been associated with the development of OA.19
As mentioned above, elite soccer players are at considerable risk of obtaining joint knee and ankle injuries. In a recent prospective cohort study by Ekstrand et al., which followed European elite soccer players for seven consecutive seasons, the overall injury rate was 8.0 injuries per 1000 hours of exposure; during matches the injury rate was as high as 27.5 injuries per 1000 hours.20 Furthermore, in a study among 91 English professional soccer clubs during two competitive seasons, ankle and knee injuries combined represented 34% of all injuries.4 In addition to this high injury rate, elite soccer players are exposed to a sport that is both high-intensity and extensive. Because these factors have been described to increase the risk of OA, the development of knee and/or ankle OA could, in the long term, pose a serious problem in this group of athletes. In 1981, a Dutch study revealed that the prevalence of knee and ankle OA is higher among former elite soccer players than in age-matched controls. Knee and ankle OA were diagnosed in 33 and 42% of former elite soccer players and in 7 and 5% of controls, respectively.21 Additionally, in 1994, Kujala et al. reported that former elite soccer players are at increased risk for the need of hospital care for knee and ankle OA than their healthy age-matched controls, which consisted of men liable for military service with an OR of 2.10.22 Furthermore, the same author conducted a study among former elite athletes, including soccer players and shooters (aged 45–68 years), that revealed that the prevalence of knee OA was 29% in former elite soccer players compared to 3% in shooters.23
Because the intensity, speed and behaviour (aggressiveness) of elite soccer have changed in recent years, the aforementioned studies may have become outdated. The purpose of this study is to systematically review the recent literature regarding the prevalence of knee and/or ankle osteoarthritis in former elite soccer players.
Section snippets
Methods
The electronic databases Medline (biomedical literature) via PubMed, Embase (biomedical and pharmaceutical literature) via Ovid and SPORTDiscus (sports and sports medicine literature) via EBCOhost were searched from 2000 to January 2012. All literature was limited to studies in humans and to English, French, German and Dutch languages. The key words and their synonyms were divided into categories to provide a systematic search. The first category consisted of synonyms for ‘elite soccer
Results
After deleting duplicate articles from the different databases and applying the inclusion criteria to the titles and abstracts, our search strategy resulted in 37 articles to be included for full text review. From these full texts, 33 were excluded for one of the following reasons: no primary study (n = 14), the population of interest did not consist of former elite soccer players, and/or the prevalence of knee and/or ankle OA was not described as an outcome (n = 17). Furthermore, the study by
Discussion
The aim of this study was to systematically review the recent literature regarding the prevalence of knee and ankle OA in former elite soccer players. Our search strategy and study selection resulted in the analysis of four studies. The studies by Elleuch et al. (2008) and Krajnc et al. (2010), which were evaluated as having a high methodological quality, found a prevalence rate of knee OA between 60 and 80%.29, 30 The studies by Drawer et al. (2001) and Turner et al. (2000), both evaluated as
Conclusion
In conclusion, the present review has shown that the prevalence of knee and/or ankle OA in former elite soccer players is high compared to the general population and to other occupations. To identify players at risk for OA, a health surveillance program could be implemented in elite soccer, and preventive measures for injuries should be made. Additionally, whether the risk of developing OA varies among different subgroups of elite soccer players, for example among different positions or age
Practical implications
- •
As the prevalence of knee and/or ankle OA in former elite soccer players is high, health surveillance program should be implemented in elite soccer, and preventive measures for injuries should be made to identify players at risk for OA.
- •
Whether the risk of developing OA varies among different subgroups of elite soccer players, for example among different positions or age groups, should be explored in order to develop and implement adequate prevention programs.
- •
With regard to the high prevalence
Acknowledgment
This project did not receive any financial assistance.
References (50)
- et al.
Relation of vigorous exercise to risk of atrial fibrillation
Am J Cardiol
(2009) An update on the pathogenesis and epidemiology of osteoarthritis
Radiol Clin North Am
(2004)- et al.
The symptoms of OA and the genesis of pain
Rheum Dis Clin North Am
(2008) - et al.
The global and regional burden of disease and risk factors, 2001: systematic analysis of population health data
Lancet
(2006) - et al.
Occupational risk factors for osteoarthritis: a meta-analysis
Osteoarthritis Cartilage
(2011) - et al.
Knee osteoarthritis in 50 former top-level footballers: a comparative (control group) study
Ann Readapt Med Phys
(2008) - et al.
A systematic review on the effectiveness of external ankle supports in the prevention of inversion ankle sprains among elite and recreational players
J Sci Med Sport
(2010) - Peterson DM. Overview of the benefits and risks of exercise. Available at: http://www.uptodate.com/home/index.html....
- et al.
Physical activity: the health benefits outweigh the risks
Curr Opin Clin Nutr Metab Care
(2004) - et al.
Soccer injury in the lower extremities
Br J Sports Med
(2005)