Dislocated Patella Symptoms & Causes

LIke ThisLIke ThisLIke ThisLIke ThisLIke This

Contact the Lower Extremity Program

  • 1-617-355-6021
  • International: +01-617-355-5209
  • Locations

Who is at risk for a dislocated patella?

•   Active teenagers and young adults from the ages of 14-20 years old
•   Participants of contact sports, such as football
•   Those suffering simple falls from a wide variety of activities such as
    gymnastics, dancing, or cheerleading
•   More girls experience knee dislocations than boys do
•   A family history of knee instability that leads to dislocation occurs in one
    fourth of patients with this problem.

What causes a dislocated patella?

The kneecap connects all the muscles in the thigh to the shinbone (tibia). As you bend or straighten your leg, the kneecap is pulled up or down. The thighbone has a V-shaped notch (femoral groove or sulcus) at one end to accommodate the moving kneecap.

In a normal knee, the kneecap fits nicely in the groove.

•   If the groove is uneven or too shallow, the kneecap could slide off, resulting in a partial or complete dislocation.
•   Laxity of the ligaments surrounding the knee
•   A sharp blow to the kneecap, as in a fall, could also pop the kneecap out of place, but this occurs in only a
    minority of cases.

What are the symptoms of a dislocated patella?

The following are the most common symptoms of a dislocated knee. However, each child may experience symptoms differently. Symptoms may include:   

•   pain in the front of the knee that increases with activity
•   swelling and/or stiffness
•   kneecap slips off to the side
•   difficulty using or moving the leg in a normal manner
•   deformity of the dislocated area
•   warmth, bruising, or redness in the injured area
•   creaking or cracking sounds during movement.

The symptoms of a dislocated knee may resemble other conditions or medical problems. Always consult your child's doctor for a diagnosis.

We are grateful to have been ranked #1 on U.S. News & World Report's list of the best children's hospitals in the nation for the third year in a row, an honor we could not have achieved without the patients and families who inspire us to do our very best for them. Thanks to you, Boston Children's is a place where we can write the greatest children's stories ever told.”
- Sandra L. Fenwick, President and CEO

Boston Children's Hospital 300 Longwood Avenue, Boston, MA 02115 617-355-6000 | 800-355-7944