Greater navicular drop tracks with kneecap pain

Patellofemoral pain is a common, multifactorial musculoskeletal complaint that mostly affects young and physically active adults, and it has a stubborn tendency to recur. Research and rehabilitation have concentrated on the hip and thigh above the knee, and on the knee joint itself, on the logic that these control how the kneecap tracks. The foot and ankle sit below the knee and shape how load is transmitted from the ground upwards, yet their contribution has stayed unclear. This review asked whether measurable foot and ankle differences actually distinguish people with patellofemoral pain from people without it.

The authors searched PubMed, ScienceDirect, SciELO and SPORTDiscus for studies comparing adults with and without patellofemoral pain on distal joint outcomes, including muscle strength, kinematics, range of motion, plantar pressure and clinical measures such as navicular drop and foot mobility. Methodological quality was rated using a modified Downs and Black scale, and each outcome was assigned a level of evidence based on quality, statistical significance and heterogeneity between studies. Random-effects meta-analyses used Hedges' g. Forty-two studies entered the systematic review and 38 the meta-analysis, comprising 2314 participants: 1211 with patellofemoral pain and 1103 controls.

The clearest signal was navicular drop, which was greater in people with patellofemoral pain (SMD = -0.46; p = 0.004) and was rated as supported by strong evidence — although that rating came from only four studies with 84 participants per group. Greater rearfoot eversion during landing and step-down tasks and greater ankle dorsiflexion during the step-down task were also seen, but with very limited supporting evidence. Several plausible candidates showed nothing: there were no significant between-group differences in ankle dorsiflexion range measured in clinical tests, in foot posture index scores, or in plantar pressure distribution. Overall, altered distal biomechanics appeared associated with the condition, but the evidence base for most individual measures was thin.

This complicates the proximal-first framing of patellofemoral pain by showing that a distal measure is reliably different between groups, while simultaneously undercutting some of the most commonly used clinical foot assessments, which did not separate the groups at all. The dissociation between a dynamic arch measure and static posture indices or plantar pressure suggests that how the foot behaves under load may matter more than how it looks at rest. The predominantly case-control design is the central limitation: it cannot say whether greater navicular drop contributes to the pain, results from it, or simply co-occurs. Prospective studies following pain-free people over time would be needed to settle direction.

If you have kneecap pain, this is a reason to think that what happens at the foot during loaded movement is worth including in an assessment, not just the hip and thigh. It is not evidence that a flatter arch caused your pain, nor that changing arch mechanics will resolve it, because the studies compared people who already had pain with people who did not. It also suggests scepticism about static foot scores and pressure readings as ways of identifying who has the problem. The practical value is mostly in knowing which measures carry signal and which, on current evidence, do not.