When a bone actually breaks into two or more pieces, it is called a complete fracture. A complete fracture can be caused by any type of trauma, including a fall off a bicycle, a car accident, or even a sports injury. Complete fractures are very painful. Some fractures are more serious than others. In a simple or closed fracture, the bone does not break through the skin. However, in an open or compound fracture, bone fragments protrude through the skin, which are more prone to infection in both the wound and the bone. Even in the case of a closed fracture in which the bone does not puncture the skin, the sharp, jagged edges of a severed bone can cut a nerve or slice through a blood vessel, which can lead to serious complications. Therefore, complete bone fractures require immediate medical attention. However, chances are, if you have a serious fracture, you will be in so much pain that no one is going to have to tell you to see a doctor. You will probably not be able to walk on your own and will need to be taken to your physician or nearby emergency room for treatment.
There are several types of complete fractures that may affect the knee bones.
Transverse. A transverse fracture, which is the most common fracture among adults, occurs when the bone is sliced into two pieces straight across the width of the bone. The ends of the bone may be jagged, and there is often soft-tissue damage.
Comminuted. In this type of fracture, the bone is smashed into little pieces like a shattered eggshell. A comminuted fracture may occur in a car accident if the knee smashes into the dashboard, and the patella gets broken up into tiny splinters.
Oblique. In an oblique fracture, the bone is broken on a slant, which is often a result of rotational force.
Spiral. In a spiral fracture, the break literally spirals around the bone, creating a long, curved fracture.