Fig. 1A–E.

The human femur normally features (A) a round head, but young and active individuals may suffer from cam-type femoroacetabular impingement (FAI) attributable to an (B) osseous bump (arrow) forming at the head-neck junction. (C) A similar situation can be surgically induced in sheep by a closed-wedge intertrochanteric osteotomy, (D) creating contact between the naturally aspherical femoral head of the sheep and the posterior acetabulum (arrows). (E) Resection of the head-neck region (arrow) can be done on the ovine FAI model as during the surgical intervention.