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ACL injury and patellofemoral pain (PFP) are rarely invited into the same conversation. One is acute, traumatic and unmistakable. The other is persistent, frustrating and often labelled ‘non-specific’. Yet when we step back from tissues and diagnoses and instead consider risk, these two conditions begin to overlap in important ways.

Both are common. Both disrupt participation in sport and physical activity. And both emerge from a complex interaction between load, movement strategies, preparation, and behaviour. The difference is not how much we understand about risk — but how often that understanding meaningfully shapes what happens in practice.

Different injuries, similar environments

ACL injuries remain most common in sports involving cutting, pivoting and jumping, with match play carrying a significantly higher risk than training [1]. PFP, meanwhile, continues to be one of the most frequent knee presentations across adolescents and adults and is a leading cause of reduced physical activity and sport participation [2].

Despite obvious differences in presentation, both conditions tend to arise in similar environments: high training loads, repeated exposure to demanding tasks, limited recovery, and pressure to perform. From this perspective, ACL injury and PFP look less like unrelated problems and more like different outcomes within the same sporting and physical activity landscape.

Risk factors: real, but rarely simple

It is important to be clear about what we do not know. There is no single causal pathway for ACL injury. Rupture does not result from one faulty movement, one weak muscle, or one missed warm-up.