Dislocated Knee

Kneecap dislocation at a glance

  • The kneecap (patella) is the part of the knee that most commonly dislocates, or moves out of its natural position.
  • In rare cases, the ligaments that connect the thighbone (femur) and the shinbone (tibia) can both become torn, causing the entire knee to become dislocated.
  • Knee dislocation is often caused by direct force, such as sports injuries, falls, or car accidents.
  • If the kneecap is already partially dislocated (subluxated) from the ligaments and tendons around the kneecap becoming weakened, it is more likely to dislocate completely when force is applied.
  • Symptoms of a dislocated knee include intense pain, swelling, visible deformity of the knee joint, and loss of joint mobility.
  • Treatment for a dislocated kneecap includes reduction (putting the bone back into its correct location), immobilization with a brace, and physical therapy.
  • Depending on the extent of the nerve, cartilage, ligament, and tendon damage from a knee dislocation, reconstructive knee surgery may be necessary, followed by rehabilitation.

Causes of kneecap dislocation

The kneecap (patella) normally moves up and down when the knee bends. Abnormalities in a person’s walking or running form (gait) can cause the kneecap to move out of its natural track over time, causing it to become partially dislocated, or subluxated.

Complete dislocation of the kneecap occurs when the patella moves to the outside of the knee, causing visible deformity of the knee joint and significant pain and swelling.

In rare cases, the entire knee can become dislocated. In a knee dislocation, the ligaments that connect the thighbone and the bones of the shin (the anterior cruciate ligament, or ACL, and the posterior cruciate ligament, or PCL) are both torn.

Symptoms of knee dislocation

A dislocated knee or kneecap is a serious, painful injury. Symptoms include severe pain, swelling, and difficulty walking or bearing weight on the affected leg. The joint will become visibly misshapen, and it may be impossible to bend or straighten the knee. The kneecap may feel loose, and the knee may feel unstable or give out.

Treatment for dislocated knee

Treatment for a dislocated kneecap includes reduction, or moving the patella back into place. The knee may then be placed in a brace to keep it from moving for several weeks. After the kneecap has healed, physical therapy will help restore strength and functionality to the knee.

If the kneecap continues to dislocate over time, surgery may be necessary.

In the case of a full knee dislocation, surgical repair and reconstruction is usually required.

Contact us to schedule an appointment with our orthopedic surgery specialists to begin treatment for your dislocated knee.