A scoping review of disease risks, evidence gaps, and research priorities with expert stakeholder synthesis
Association football and rugby provide substantial physical, psychological, and social benefits, but their long-term implications for knee health remain poorly defined. Better understanding of relationships between participation, injury, and later knee morbidity is needed to support athlete health without undermining the wider benefits of sport participation.
To map the literature on post-play knee health in former football and rugby players, define the major limitations of the current evidence base, and identify research priorities to strengthen future athlete health research.
PRISMA-ScR scoping review with descriptive and thematic synthesis informed by multidisciplinary expert stakeholders.
37 studies were included, representing 17,162 former players (mean age 48.1 years; 92% male). The evidence base was predominantly cross-sectional (34/37 studies), with only one prospective cohort study; 29/37 studies focused on former professional players and 31/37 included male-only cohorts. Reported knee osteoarthritis prevalence generally exceeded general population estimates. Severe knee injury, particularly ACL or meniscal injury, and prior surgery were the factors most consistently associated with later pain, functional limitation, OA, and need for further surgery. However, the literature was limited by heterogeneous outcome definitions, retrospective exposure assessment, likely selection bias, limited longitudinal follow-up, and inequitable representation.
Former football and rugby players may experience greater later knee morbidity, particularly after significant knee injury, but the current evidence base is insufficient to define this risk precisely. The more important finding may be the shortfall in robust, inclusive evidence. These findings provide a platform for a staged multi-stakeholder consensus process to define future research priorities, recommended study designs, and practical structures for strengthening long-term athlete health research.
Reported knee OA prevalence generally exceeded general population estimates, but wide variation in how outcomes are defined makes direct comparison difficult. The independent contribution of sport participation, separate from injury burden, cannot yet be established with confidence.
"Football and rugby confer substantial physical, psychological, social, and cultural benefits. This review strengthens the evidence base supporting athlete welfare, not discouraging participation. Risk communication must reflect genuine uncertainty and the many benefits of play."
The current evidence demonstrates elevated morbidity but cannot define its true magnitude, establish causality, or characterise how risk differs across player groups. The more important finding of this review may be the shortfall in robust, inclusive evidence.
Despite a growing body of literature, several critical questions remain unresolved. These gaps define the priority agenda for future research.
Future work must move beyond cross-sectional prevalence towards longitudinal, standardised, inclusive research that establishes causality and informs clinical practice. This review provides a foundation for a staged multi-stakeholder consensus process.
A one-page visual summary of the key findings, methodological limitations, and research priorities from this scoping review.
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