AO Classification of Femoral Head Fractures

AO Classification for Femoral Head fractures: 31 C (3=Femur, 1=Proximal femur, C=femoral head)

Femoral head Split fractures are classified by AO/OTA as 31C1 and subdivided into:

31C1.1 – Avulsion of ligamentum teres
31C1.2 – Infrafoveal split fracture
31C1.3 – Suprafoveal split fracture

Femoral head Depression fractures are classified by AO/OTA as 31C2 and subdivided into:

31C2.1 – Chondral lesion
31C2.2 – Depression impaction fracture
31C2.3 – Split depression fracture