What is knee dislocation?
It is a problem in the knee in which the patella (bone that we feel in the front part of the knee) is displaced and does not maintain its correct position (dislocation).
Normally it is displaced towards the external zone of the knee. In addition it can be recurrent, that is to say, new episodes of this dislocation can exist.
Why does knee dislocation occur?
This problem is more frequent in girls or adolescent women. There are numerous factors that contribute to suffer them:
1- Alterations in the formation, development and shape of the bone.
- Genu valgus or “X” legs.
- Alterations in the rotation of the bones of the leg.
- High patella.
2- Alterations in the muscle and ligaments.
- Weak quadriceps muscle (in the anterior part of the thigh).
- Rupture of the ligaments that hold the patella to the femur (medial patellofemoral ligament) by direct trauma.
- Increased joint laxity. The child has more motion than normal.
How does knee dislocation present?
- The knee appears to be deformed.
- The knee is bent and cannot be straightened.
- The kneecap (patella) dislocates outward from the knee.
- Knee pain and swelling.
What do the symptoms look like in the future?
- The patella appears “loose”: it may move excessively from right to left (patellar hypermobility).
- The first few times the dislocation occurs you will feel pain and be unable to walk. However, if they keep occurring and are not treated, you may feel less pain and have less immediate ability.
- Dislocation of the kneecap damages the knee joint causing problems in the adult.
What tests should I have?
- X-rays: to examine all sides of the joint.
- Magnetic resonance imaging (MRI) or computed tomography (CT): to evaluate the cartilage or bone of the knee.
What is the treatment?
When the patella is dislocated, you should go to the emergency department for evaluation by a physician. The patella will be manipulated by trained personnel and the knee will be placed in an immobilizer or cast to prevent movement (usually for 3 weeks).
It will then be evaluated by an orthopedic surgeon who may order physical therapy to help restore muscle strength and improve range of motion. In addition, treatments such as knee braces may be helpful. Finally, surgery is indicated when dislocations are frequent and the patient is disabled.