A dislocated knee is a serious injury where the thighbone (femur) loses contact with the shinbone (tibia), often caused by a significant force pushing or bending the knee beyond its limits. This injury is very painful, causes swelling, and makes it impossible to walk. It also frequently damages the ligaments, tendons, arteries, and nerves around the knee, sometimes requiring urgent surgery to restore blood flow and prevent tissue death or amputation. Diagnosis is done by physical examination and confirmed with x-rays and CT angiography, especially to check for artery damage. Treatment involves repositioning the joint (often under sedation), splinting, and usually surgical repair later. This type of knee dislocation is different and much more serious than a kneecap (patellar) dislocation, which involves the kneecap sliding out of its groove on the thighbone and tends to have less severe complications though it also requires medical assessment and sometimes surgery.
Symptoms of a Dislocated Knee
- Visible deformity of the knee
- Severe pain and swelling
- Inability to walk or bear weight on the leg
- Possible numbness or pale appearance of the lower leg, indicating nerve or artery damage
Risk and Causes
- High-impact trauma such as car accidents
- Twisting injuries or falls, sometimes even minor in obese individuals
- Often damages multiple knee-support structures
Diagnosis and Treatment
- Clinical exam with confirmation by x-rays and CT angiography
- Immediate reduction (putting the joint back in place) under sedation
- Checking and repairing artery injuries urgently when present
- Surgical repair of ligaments typically needed afterward
This injury requires emergency medical attention due to risks of blood vessel damage and permanent joint instability.
