injuries and poisoning
Knee Dislocations
Diagnosis of a Dislocated Knee
X-rays Physical examination Evaluation of arteries and nerves, usually with computed tomography (CT) angiography If people suspect that their knee is dislocated, they should go to an emergency department right away. People who may have a dislocated knee should go to an emergency department immediately. Doctors can usually identify a dislocated knee when they examine the joint. However, X-rays are taken from several angles. Unless the knee has slipped back into place on its own, x-rays can confirm the diagnosis. X-rays can also identify fractures. To determine whether arteries are damaged, doctors check for a pulse in the lower leg, usually several times over a period of time. They may also compare blood pressure in the affected leg with that in the arm or the other leg. However, CT angiography is the best way to check for damage to arteries after the knee is dislocated. If any symptoms and findings suggest that tissues are not receiving enough blood, doctors consult with a surgeon about repairing the damaged arteries. Identifying damaged arteries promptly is essential because if the tissues in the lower leg are deprived of oxygen for more than 8 hours, amputation is much more likely to be needed. If arteries are not damaged, doctors gently move the joint to determine how badly the ligaments are damaged. Doctors also check for nerve damage—for example, by asking the person to move the foot up and down and to turn the foot in and out and by testing for numbness. 