A patella fracture is a break in the small bone that sits at the front of your knee, commonly known as your kneecap. It is among the least likely knee injuries but can be extremely painful and debilitating. The cause is usually a direct blow to the knee from a fall or collision. Common symptoms of a patellar fracture include pain and swelling at the front of the knee. You may also see bruising and experience difficulty straightening your knee and walking.
Patella fractures can be categorised as displaced or nondisplaced. Displaced fractures occur when the fracture causes bones to misalign. These are more difficult to treat. Nondisplaced fractures are vertical fractures that allow the bones to remain aligned.
There are four types of patella fractures:
- Stable fracture. A vertical, non-displaced fracture in which the pieces of the bone remain in contact with each other or separate only marginally. The bones usually stay aligned during healing.
- Displaced fracture. A break in which the ends of the bone become misaligned and disrupt the normally smooth joint. Reassembling the pieces of bone requires surgery.
- Comminuted fracture. The bone shatters into three or more pieces. Can be stable or nonstable.
- Open fracture. The break is such that the bone sticks out from the skin or the wound cuts down to the bone. This type of fracture usually involves damage to the soft tissues that surround the bone. Recovery is prolonged.