A knee dislocation happens when the bones that form your knee are out of place. The bones of your calf (tibia and fibula) get moved compared to the bone of your thigh (femur). The knee bones are held together by strong bands of tissue called ligaments. For a dislocated knee, these bands have to tear. Knee dislocations are rare. They usually happen after a major trauma including falls, car crashes and other high speed injuries.
- If the knee is dislocated, it will look deformed. The usual straight line of your leg will be crooked.
- Sometimes, dislocated knee can relocate on their own. In this case, the knee will be very swollen and painful.
Specifically, there will be a large amount of pain in the knee. Sometimes, there will be no feeling below the knee. You may not be able to feel a pulse (your heartbeat) in your foot. Seek care if:
- Extreme pain or swelling after a serious injury
- A deformity of your knee
- Numbness in foot
- No pulses in foot
Depending on how your knee looks, you can expect the doctor to check injury in the following ways:
- X-rays will be taken to make sure there are no breaks in the bone.
- Examination of pulses: Injury to the knee arteries is common with this injury. The doctor will make sure there are pulses in your foot.
- Arteriogram (x-ray of artery): This may need to be done to make sure there are no injuries to the artery. Some medical centers may also use special ultrasound or Doppler machines (sound wave) to assess the blood flow in your arteries.
- Nerves also run through your knee, so it is possible that they may have been damaged. The ability to feel, touch and move certain muscle groups are the main ways nerves are tested. Specifically, the ability to move your foot up and down and to turn your foot inside and outside are important muscle movements to check for. Any feeling of numbness is concerning for nerve injury.
Placing ice on the injured area may help some pain control and decrease some swelling. But the most important treatment is to have a doctor assess the injury and relocate or put the knee back in place. The pain and injury of a knee dislocation can lead to patellar tendonitis later.
- Relocation: The doctor will move your lower leg back into position.
- Immobilization: To avoid further injury and to help with the beginning of healing, the entire knee joint will be kept in a splint or immobilizer. This will keep the knee from bending and help the tissues to start healing.
- Referral: A dislocated knee always has severe tears of ligaments and sometimes has breaks in the knee bones. After swelling is reduced, the knee may need surgery to regain function. You will have to see a bone specialist (orthopedist) after this injury.
- Attempt to avoid major accidents.
- Avoid risky activities such as skiing, motorcycle riding or jumping from high places.
- Almost all knee dislocations require surgery because major injury to the artery occurs in 21-32% of all knee dislocations.
- After appropriate treatment and surgery, however, results have been good. Knees return close to normal in most cases. Chronic pain is a common problem occurring in 46% of cases.