Patellar Fracture

By Ashley Henshaw. May 7th 2016

You may be playing tag with your friends, when you trip on a rock as you are being chased. When you land on your knee, you feel a sharp pain around your knee cap, and you can no longer straighten your leg. What you are most likely experiencing is a patellar fracture.


Patellar fractures are known in common terms as simply, a broken knee. The patella is the bone that creates the knee cap bone, which shields the meeting point of the thigh bone and shin bone. There is a thin shield of cartilage beneath the patella (so it can be moved around) as the bone also connects the muscles and tissues of the upper and lower leg.

A broken kneecap is a common injury that can be caused by a direct blow or excessive pressure on the bone. It should be treated immediately and may require surgery. If treated improperly it can lead to stiffness, weakness, or arthritis in the long run.

Some common causes of patellar fracture include:

  • Sharp blow to the knee, such as that from a fall or from a car accident
  • Over exercising on a knee that is not completely healed
  • Weight lifting that causes stress on the knee
  • Stair climbing (more commonly in older people)

Types Of Fractures

There are several ways to break or fracture a bone. Here are the most common types of patellar fracture:

  • Stable (non-displaced) fracture. This is a fracture that looks like a straight crack across the bone, so that the broken ends are still aligned. The bones can stay in place for proper healing.
  • Displaced fracture. This type of fracture involves broken bones that have moved from their original place, so it does not line up with the original bone. Surgery will be required to fix this fracture.
  • Comminuted fracture. The patella is shattered into three or more pieces, and is extremely unstable. Surgery is required to realign all the bones for proper healing.
  • Open fracture. In this type of fracture, the broken bone fragments pierce the skin so that it becomes exposed. Usually, the surrounding tissues and tendons are also damaged, and will take a longer time to heal with higher risk for infections and complications.

Signs And Symptoms

Typically, it becomes very evident for affected individuals that they’ve broken their kneecap. For open fractures, the bones will obviously be seen from the torn knee. For smaller fractures, it may not seem or feel as evident. Here are some signs and symptoms of a patellar fracture:

  • Extreme bruising at the knee
  • Inability to walk
  • Inability to straighten the knee
  • Swelling and tenderness
  • Sudden, excruciating pain on the knees
  • Sometimes, a cracking sound can be heard as the bone fractures

Risk Factors

Some individuals are at higher risk than others for a patellar fracture. They include:

  • The elderly
  • Postmenopausal women (who have decreased bone mass)
  • People with decreased muscle mass
  • Men (higher incidents of patellar fracture than women)
  • Active individuals between ages of 20 to 50
  • Individuals with osteoporosis
  • Individuals who participate in contact sports
  • Obese individuals (which strains knee ligaments and muscles)

Always be sure to take precautions when putting pressure on the knees, and be sure to wear protective knee gear as appropriate.


Depending on your situation and your x-rays, the orthopaedic surgeon may choose either a surgical or non-surgical approach to heal the fracture.

  • Non-surgical approach. If the x-ray pictures indicate a stable fracture, your doctor may choose to place the knee in a cast to heal. Pain medication may be prescribed for the healing process.
  • Surgical approach. If the fractures are not aligned, the doctor may use the surgical approach. He or she may either use metal pins and screws to piece the patella back together, or remove the kneecap completely and install a new, artificial cap. Surgery recover takes a few weeks to a few months, depending on the seriousness of the injury.

Whether the treatment method is of surgical or non-surgical in nature, physical therapy will almost always follow to ensure full recovery of the knee. Be sure to not strain or use the healing knee until a physician says it is ok to do so, or you may face more serious complications of the knee down the road.

Rather than treating any potential knee injury as a sprain or mild dislocation, it is best to seek medical care to make sure you don’t need further medical treatment, like surgery. It is always better to be safe than sorry.


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