Foot and Ankle Contributions to Noncontact ACL Injury Risk: A Systematic Review
Orthopaedic journal of sports medicine · 2026
48 mostly low-quality studies suggest foot/ankle mechanics matter for ACL risk, but with no pooled effect size, it's a hypothesis-generator, not a practice-changer.
The paper
Systematic review (Level of evidence 4), 48 studies pooled from 1772 screened, on foot/ankle biomechanical contributions to noncontact ACL injury risk.
What they found
33/48 studies (68.8%) found factors associated with increased ACL risk; 81% of studies reported statistically supported findings. Greater rearfoot eversion/inversion, increased dorsiflexion, medial arch collapse, and rearfoot/flatfoot or toe-in/toe-out landing patterns were commonly linked to higher risk, while forefoot landing was protective; no pooled effect sizes or meta-analytic estimates were reported.
The appraisal
This is a narrative-style systematic review of heterogeneous, predominantly noncomparative studies (case-control, cross-sectional, retrospective cohort), with quality assessed by MINORS and described as generally low. There is no meta-analysis, no pooled odds ratios or risk ratios, and no quantification of effect magnitude — 'commonly associated' and 'consistently linked' are vote-counting descriptions, not effect sizes. Without comparator strength, confidence intervals, or adjustment for confounders (sport, sex, prior injury clustering) across studies, statistical significance in individual studies tells us almost nothing about how much foot/ankle mechanics actually contribute to ACL risk relative to known dominant factors (e.g., knee abduction moment, neuromuscular control).
The gap
There is no quantitative synthesis — you cannot tell from this review whether foot/ankle factors are a minor modulating influence or a major independent risk factor, because no pooled effect size, dose-response, or prospective injury-incidence data are presented.
Landmark context
This sits downstream of the biomechanical ACL injury literature dominated by frontal/sagittal plane knee loading models (e.g., Hewett's neuromuscular/knee abduction moment work), and extends that lens distally to the foot/ankle — an area the authors explicitly flag as understudied; it does not overturn or directly replicate any single landmark trial.
What to do Monday
No change to Monday practice: this supports continuing to assess foot strike pattern, rearfoot alignment, and toe progression as part of a broader ACL risk screen and cueing forefoot/midfoot landing during jump-landing training, but it does not justify treating foot/ankle mechanics as a primary, evidence-quantified target over established neuromuscular ACL prevention programs (e.g., FIFA 11+, cutting/landing mechanics retraining).
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