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Published on: April 30, 2014
Coronal alignment increases ACL strain in vitro but lacks consistent clinical association with graft failure: A
Joshua T Bram1, Tyler Khilnani1, Mark F Megerian1
1Hospital for Special Surgery Sports Medicine Institute New York New York USA.
Purpose:
The purpose of this systematic review was to evaluate the existing literature on the impact of radiographic varus/valgus alignment on primary ACL rupture and graft failure.
Methods:
Three online databases (PubMed, Embase and Cochrane Library) were searched for the period of database inception until 31 July 2025. All clinical, biomechanical, or computational investigations assessing the influence of bony coronal plane alignment on primary ACL rupture/graft rupture were included. Study quality was assessed using the Methodological Index for Non-Randomized Studies (MINORS) for clinical studies and Quality Appraisal for Cadaveric Studies (QUACS) scale for biomechanical studies.
Results:
Thirteen studies met inclusion criteria: four cadaveric (38 specimens) and nine clinical investigations. Cadaveric studies demonstrated a biomechanical disadvantage of mechanical axis deviation, with both excessive valgus and varus alignment increasing native ACL or ACL graft strain in vitro (11%-72% increase relative to neutral alignment). Up to 72% increased graft strain was observed with increased valgus alignment, suggesting valgus may pose greater biomechanical risk than varus. Conversely, clinical evidence for coronal malalignment as a risk factor for ACL rupture or ACL graft rupture was inconsistent. Some studies reported increased valgus alignment in ACL-injured versus uninjured limbs, while others found no differences in either primary or revision ACL reconstruction setting. An association between greater varus alignment and inferior graft maturation was suggested.
Conclusion:
While biomechanical evidence indicates that both varus and valgus coronal malalignment increase ACL strain, the corresponding clinical evidence for its association with ACL rupture or ACL graft rupture remains limited. Based on the synthesis of data, preliminary thresholds of >5° valgus and >8° varus merit investigation as potential risk factors for ACL rupture/graft rupture. Given the lack of literature on this topic, further investigation is required to determine the effect of coronal malalignment on risk of ACL rupture and clinical thresholds that merit additional surgical intervention.
Level Of Evidence:
Level IV.