Patella (Kneecap) Dislocation

Jeffery Housner, M.D.


  • Occurs when the patella comes out of place. An obvious visual deformity of the knee is noted.
  • Usually the result of a trauma. Sometimes the kneecap reduces on its own or the patient is able to reduce it. Other times this need to be reduced at an Emergency Department.
  • Associated with pain, swelling, and inability to weight bear.
  • The cartilage behind the patella can be damaged.


  • X-rays are obtained to evaluate for fracture. It is common to see a small fracture on the medial side of the patella, called an avulsion fracture.
  • MRI can be used to evaluate injury to the cartilage or ligaments in the knee.


  • First time dislocations without significant fracture are treated with rest, bracing, and physical therapy.
  • Large fractures often require surgical reduction and fixation.
  • Recurrent patellar instability is treated with surgery. Surgical procedures to stabilize the patella include: medial patellofemoral ligament reconstruction, medial retinacular repair, and tibial tubercle osteotomy.

Post-operative Care:

  • Most patients are able to go home the day of surgery. In some cases, patients stay in the hospital overnight.
  • Crutches and a brace (or splint) are needed for about one month after surgery.
  • Range of motion is restricted for 4-6 weeks to protect the repair.
  • Physical therapy is necessary for 3-6 months to regain full motion and strength.
  • Full recovery with return to sports at about 6 months after surgery.