The kneecap (patella) is normally positioned over the front of the
knee joint at the base of the thighbone (femur). A kneecap can be dislocated,
or moved out of its normal position, when:
- The kneecap is out of place (patellar tracking disorder) and force is applied, causing dislocation.
foot is firmly planted pointing outward, and the knee is bent with the thigh
turned inward. This kind of injury is common during many sports
- The inner edge of the kneecap is hit, pushing it toward
the outer side of the leg.
- The knee is swollen and force is
applied, causing dislocation.
Symptoms of a dislocated kneecap may include:
- Severe pain.
- A misshapen knee that
looks like a bone is out of position.
- A popping sensation, followed
by a feeling that something is out of place.
- Inability to bend or
straighten the knee.
- Knee swelling.
- Cool, pale skin or
numbness and tingling in or below the affected knee.
A dislocation can cause other problems even if the bone pops back
- If the dislocation was due to a preexisting
malalignment, the knee may dislocate again.
- Ligaments, tendons,
muscles, and cartilage in or around the joint may stretch or
- A piece of bone may break off somewhere in the knee