Compound patellar fracture

Compound patellar fracture

This patient suffered direct trauma to the front of his knee and presented to the ED with an extensive laceration. The AP view, left, shows a vertical fracture of the patella (yellow arrows). What tells us, radiographically, that this is a compound fracture is that a large amount of lucent gas (orange arrows) is visible in the joint on the lateral radiograph. Note how the fracture is not visible on this view, re-emphasising the requirement for orthogonal views in the setting of extremity trauma. The knee joint was washed out and the fracture fixed with transverse screws, right-hand intra-operative fluoroscopic image.