What are the biggest causes of fracture of knee cap?

Direct trauma... Direct trauma, either from a fall or a car accident are the most common causes of a patella (knee-cap) fracture.
Trauma to the knee: Direct injury to the kneecap will mostly result in a shattered bone (comminuted fx); a fall after catching your foot on something (indirect injury) will cause a transverse fx (mostly 2 fragments, maybe 3).
Patella fracture. Mechanism of injury is usually direct trauma. Less common is eccentric pull from a fall, which may cause avulsion injury.

Related Questions

What are some of the symptoms of fracture of knee cap?

Pain and deformity. Fractures of the kneecap are uncommon as it takes quite a bit of force to break the kneecap - if you do break it then you will have severe pain, swelling, tenderness and feeling of crepitus (like rice krispies under the skin). Read more...
Pain is #1. Hi, pain is the big one. Pain in the anterior aspect of the knee. Look for swelling, redness, and warmth over the patella or knee cap. If the fracture is bad enough and displaced there can be fracture gap and dysfunction of the extensor mechanism. In other words, it may be hard to straighten (or extend) your knee. After your doc checks you out, x-ray is the place to start the imaging evaluation. Read more...

What can happen years after fracture to the knee cap?

Arthritis. The biggest concern would be the development of secondary arthritis. This can cause pain, limit mobility and cause problems walking or being physically active. Appropriate fracture care is very important to try to prevent this. Read more...
A recent study shows. If the fracture was operated on: up tp 50% will need hardware removal, 40% will have knee pain, %40 will have restricted range of motion, 20% will not have full extension of their leg and %30 will have some weakness in their knee extension. Read more...

How would you know if a knee cap was fractured?

If it healed. Already may be more difficult but xray is the first line of diagnostic testing... Read more...
Patellar fracturw. The kneecap can crack just slightly, or can be broken into many pieces. A direct fracture occurs due to a fall or direct blow. An indirect fracture occurs when the thigh muscle contract so strongly that the patella breaks. If you have a patellar fracture you may have bruising swelling, inability to straighten the knee and inability to walk, After examination, an X-ray can be ordered. Read more...

I hit the top of my knee cap and it is swollen. It hurts when I bend or touch it. It has been aching for a day 1/2.Is it fractured or dislocated?

Xray to assess fx. Depending upon the degree of trauma and force imparted upon the patella (kneecap) determiness the risk for fracture. Bony tenderness to palpation would indicate a need for X-rays. Seek evaluation by an orthopaedic surgeon for persistent symptoms. Read more...