A dislocated knee, also known as a tibiofemoral dislocation, occurs when the bones of the knee joint—the thigh bone (femur) and the shin bone (tibia)—are completely displaced from their normal alignment. This injury is distinct from a dislocated kneecap (patellar dislocation). A true knee dislocation is a severe and uncommon injury, often resulting from high-energy trauma such as car accidents, significant falls, or certain sports injuries. It is a medical emergency that requires immediate attention due to the potential for serious associated damage.
Immediate Care at the Scene
Upon suspecting a knee dislocation, immediately contact emergency services. While waiting for professional medical help, keep the injured person still and avoid any attempts to move the knee or force it back into place. Manipulating the joint can worsen existing injuries to surrounding tissues, nerves, or blood vessels.
The injured leg should be immobilized in the position it was found, using padding and bandages to provide support above and below the knee. Applying ice packs wrapped in a cloth to the area can help reduce swelling and discomfort. Elevating the leg, if possible without causing more pain, can further assist in managing swelling.
Check for signs of potential nerve or blood vessel compromise. Assess the foot for a pulse, normal sensation, and a healthy color. Changes like numbness, tingling, coolness, or pallor suggest a possible neurovascular injury and should be immediately communicated to emergency responders.
Emergency Medical Intervention
At a medical facility, healthcare professionals will conduct a thorough assessment, including imaging studies. X-rays confirm the dislocation and identify any associated fractures. Magnetic resonance imaging (MRI) is often used to evaluate soft tissue structures like ligaments, menisci, and cartilage, providing detailed information about the extent of the injury.
Damage to the popliteal artery, a major blood vessel behind the knee, is a significant concern. Vascular status is carefully assessed, sometimes through an ankle-brachial index (ABI) or computed tomography (CT) angiography, especially if pulses are diminished or absent. Prompt diagnosis of vascular injury is important, as delayed treatment can lead to serious complications.
Closed reduction, the process of manually returning the knee bones to their correct position, is performed only by trained medical professionals. This procedure often requires sedation or anesthesia to relax muscles and manage pain, allowing the healthcare provider to gently guide the bones back into alignment.
Immediately following reduction, the neurovascular status of the limb is reassessed to ensure blood flow and nerve function have not been compromised. If a vascular injury is confirmed or suspected, an urgent consultation with a vascular surgeon is typically required. Surgical intervention may be necessary to repair damaged blood vessels, with time being important for limb preservation.
Post-Reduction Management
After the knee is successfully reduced, the joint is typically immobilized to protect it during the initial healing phase and prevent re-dislocation. This often involves a brace or splint, which may hold the knee in a slightly flexed position. The duration of immobilization varies, typically for several weeks, depending on injury severity and physician recommendations.
Pain management is a key part of post-reduction care, often involving prescription pain medication or over-the-counter anti-inflammatory drugs. Elevating the leg and applying ice packs help reduce swelling and discomfort. Protecting the joint from undue stress is important for optimal healing.
Initial follow-up appointments are scheduled to monitor the knee’s stability and healing progress. These may include further imaging to assess the integrity of ligaments and other soft tissues. Decisions regarding further treatment, such such as surgical repair, are often made based on these evaluations.
Rehabilitation and Long-Term Recovery
Rehabilitation following a knee dislocation is a comprehensive process to restore the knee’s full function, strength, and stability. Physical therapy typically begins with exercises focused on regaining range of motion, gradually increasing flexibility as healing progresses. Early, controlled movement helps prevent stiffness.
Strengthening exercises are introduced to rebuild muscles around the knee, particularly the quadriceps and hamstrings, which support the joint. Balance and proprioception exercises improve the knee’s ability to sense its position and movement, which helps prevent future injuries.
The timeline for recovery varies significantly depending on the extent of the initial injury. While some individuals regain function within several weeks, a full return to activities, especially sports, can take many months. Consistent adherence to the prescribed physical therapy program is important for achieving the best possible long-term outcomes.
Recognizing Potential Complications
Despite immediate and appropriate treatment, knee dislocations can lead to several complications. Injury to the popliteal artery is a serious complication, potentially resulting in compromised blood flow to the lower leg and foot. Signs include a cool foot, changes in skin color, or a diminished pulse, warranting immediate medical re-evaluation to avoid irreversible damage, including the potential for amputation.
Nerve damage, such as to the peroneal nerve, can also occur, leading to numbness, tingling, or weakness in the foot. While some nerve injuries may recover, others can result in lasting functional deficits. Prompt identification allows for appropriate management and monitoring.
Long-term issues such as chronic instability of the knee joint can develop due to significant ligamentous damage. Post-traumatic arthritis may also occur years after the injury, as joint surfaces can be affected. Arthrofibrosis, characterized by excessive scar tissue formation leading to joint stiffness, is another complication that can limit range of motion.