What is a Dislocated Knee?
A dislocated knee is an extremely serious knee injury in which the thigh bone and shin bone completely lose contact with each other. It is not the same as a patellar dislocation, also called a “kneecap dislocation,” in which the kneecap slips out of its groove at the end of the thigh bone.
A dislocated knee typically occurs as the result of high-energy trauma, such as an automobile accident, sports injury, or severe fall. When the knee dislocates, a great deal of tissue damage occurs around the knee joint, as well as to the ligaments. In most cases, both the anterior cruciate ligament (ACL) and posterior cruciate ligament (PCL) are torn, and cartilage and meniscus also can be damaged. Of particular concern is damage to the vascular and nerve structures around the knee, which can be so severe that a patient may need emergency vascular surgery.
Symptoms of a Dislocated Knee
Individuals who have a dislocated knee will experience a great deal of pain in the knee, and may have no feeling below the knee joint. They may also be unable to feel a pulse in their foot.
Treatment of a Dislocated Knee
X-rays are performed to determine that the individual truly has a dislocated knee. The main concern is immediate treatment of any nerve or vascular injuries, so doctors typically order special tests of the blood vessels (an angiogram) to evaluate them. Once the blood vessels and nerves are determined to be healthy, surgery is usually necessary to reconstruct the damaged ligaments, usually both the ACL and PCL. Any damaged cartilage and meniscus tears are also repaired.
A course of physical therapy is necessary after surgery to minimize knee stiffness and chronic instability of the knee joint.