A true knee dislocation (tibiofemoral dislocation) is an extremely rare and severe orthopedic injury where the thigh bone (femur) and the shin bone (tibia) lose all contact. This is fundamentally different from a common kneecap (patellar) dislocation. The answer to whether an individual can walk on a truly dislocated knee is clear: they cannot. The structural damage is so profound that weight-bearing is physically impossible and risks catastrophic harm to the leg.
The Extreme Severity of a Knee Dislocation
A true knee dislocation is a complete separation of the tibiofemoral joint, the main hinge of the leg. This injury requires immense force, resulting in the tearing of multiple major stabilizing structures. These often include all four primary ligaments:
- Anterior cruciate ligament (ACL)
- Posterior cruciate ligament (PCL)
- Medial collateral ligament (MCL)
- Lateral collateral ligament (LCL)
This extensive ligamentous damage compromises the entire joint structure. The lower leg segment becomes wholly unstable and unable to support the body’s weight. The leg often presents with a dramatic and obvious deformity, making weight-bearing physically impossible.
Critical Associated Vascular and Nerve Damage
The severity of this injury extends beyond the bones and ligaments, as a knee dislocation places the leg’s main artery in immediate jeopardy. The popliteal artery runs directly behind the knee joint. When the tibia and femur separate, the artery can be stretched, torn, or completely severed.
Popliteal artery injury is a limb-threatening complication. If blood flow to the lower leg is not restored within six to eight hours, the risk of tissue death and eventual amputation rises significantly. This vascular injury may still be present even if the joint spontaneously reduces, which occurs in about half of all cases before medical attention.
Damage to the nerves is also common, particularly the common peroneal nerve, which wraps around the outside of the knee. Injury to this nerve can cause “foot drop,” leading to the inability to lift the front part of the foot. Damage to the peroneal or tibial nerve can result in loss of sensation and significant long-term functional impairment of the foot and ankle.
Immediate Emergency Protocol
Given the high risk of catastrophic neurovascular complications, a suspected knee dislocation demands immediate emergency action. The single most important step is to call for emergency medical services (911 or local equivalent) without delay. This is a time-sensitive, potentially limb-threatening injury that must be managed by professionals.
The injured leg should be kept completely still and supported in the position in which it was found. It is crucial to avoid attempting to move the limb or straighten it. Moving the joint can worsen an existing vascular or nerve injury. Until help arrives, the person should be kept calm and warm to manage shock.
A bystander can monitor circulation by checking for a pulse below the injury or by assessing capillary refill time in the toes. Any change in the color, temperature, or sensation of the foot should be noted and communicated immediately to emergency responders. The injured person must not be allowed to attempt to bear any weight.
Hospital Treatment and Recovery
Once the patient arrives at the hospital, the immediate priority is to realign the joint through a procedure called closed reduction. This relieves pressure on the popliteal artery and minimizes further soft tissue damage. Following reduction, a comprehensive vascular assessment is performed, typically using a Computed Tomography Angiography (CTA).
If a vascular injury is confirmed, an emergency operation is performed to repair the damaged artery, often within the critical six-to-eight-hour window to save the limb. After the initial emergency is addressed, extensive surgery to reconstruct the torn ligaments is almost always required to restore stability. Recovery is prolonged, involving several weeks of immobilization followed by intense physical therapy and rehabilitation.