The patella (or kneecap) normally moves up and down in a groove on the front of the femur (thigh bone) as we bend and straighten our knee. The patella will sometimes come out of its groove during an injury. This is known as a dislocation of the patella or a patellar dislocation. It occurs most commonly in teenagers when the knee twists a specific way. Patients who sustain this injury may recover and do well or may have dislocations continue to occur from time to time. On some occasions, as the patella dislocates it scrapes cartilage off the side of the groove creating a loose piece that needs to be removed.

Causes & Triggers

  • Typically a result of injury
  • Occurs commonly in teens when knee twists a specific way
  • Specific patient anatomy may contribute to dislocation

Signs & Symptoms

  • Patella dislocates to outside of knee
  • Knee pain or tenderness
  • Swelling
  • Difficulty straightening knee

Tips & Treatments

Not all patellar dislocations are the same. We can better appreciate the individual nature of a patellar dislocation to help determine if the optimal treatment may be rehab with no surgery, surgery to reconstruct the MPFL (ligament) or more involved surgery to correct a flat or convex groove.