What should you know about patellar dislocation injury?

The kneecap normally glides in a channel at the front of the thighbone. A twist, change of direction, fall, or direct impact can push it sideways. The supporting soft tissues may stretch or tear, and a small piece of bone or cartilage can sometimes be injured.

Pain, swelling, a visibly altered knee shape, and difficulty bending or straightening are possible. Some people later notice the knee giving way or fear that the kneecap will move again. A clinician uses the injury story and examination, with imaging when needed, to plan safe recovery.

Stop the activity, support the leg, and avoid trying to force the kneecap back into place yourself. Keep weight off the leg if walking is painful. A healthcare professional can reduce the dislocation safely and check circulation, nerve function, and associated injuries.

After the acute phase, care may include a brace, gradual range-of-motion work, and physiotherapy to rebuild control of the quadriceps and hip. Read about [Knee Bracing](/treatments/non-surgical-orthopedics/knee-bracing/) and [Physiotherapy](/treatments/physiotherapy-and-rehabilitation/physiotherapy/). Recurrent instability or a structural injury may lead to discussion of [MPFL Reconstruction](/treatments/sports-and-arthroscopic-surgery/mpfl-reconstruction/).

Seek emergency care if the kneecap remains out of place, the leg looks deformed, the foot becomes cold or numb, or you cannot move the knee. Prompt assessment is also needed after a first dislocation, even if the kneecap seems to have returned, because swelling and internal injury can be missed.

Ask whether the kneecap reduced completely, whether the ligaments or cartilage were injured, how long a brace is needed, and which exercises are safe. Discuss warning signs during recovery and what would change the plan if the knee gives way again.