The plantar calcaneonavicular ligament (spring ligament) in its complete form is the three-component complex (superomedial band, inferoplantar longitudinal band, and inferoplantar oblique band) connecting the sustentaculum tali to the plantar navicular. It is the primary static talar head support.
Supports the talar head from its plantar and medial aspects, maintains medial longitudinal arch height, acts synergistically with the tibialis posterior tendon as the primary medial arch static stabiliser, and seals the talonavicular joint space medially.
Spring ligament insufficiency is a key component of adult acquired flatfoot deformity. MRI demonstrates signal change in the superomedial band in early failure before complete tearing. Comprehensive spring ligament reconstruction using native tissue plication or allograft augmentation is the cornerstone of Stage II flatfoot reconstruction.
Superomedial spring ligament repair or reconstruction combined with FDL tendon transfer and medial displacement calcaneal osteotomy in Stage II adult acquired flatfoot, restoring medial arch support.
MRI signal change (T2 hyperintensity) within the superomedial spring ligament band is the earliest imaging finding of spring ligament complex failure in progressive flatfoot, indicating surgical intervention.
