Knee dislocations usually occur once the end of the femur is no longer in contact with the tibia or shinbone. The knee can end up dislocated once the lower leg is driven forward beyond the normal range of the knee joint. In such cases, the shinbone is thrusted in the front part of the thighbone. The shinbone might also be driven behind the thighbone or to either side. Most cases of knee dislocations stem from significant force such as during high-speed vehicular accidents. Oftentimes, minimal jarring such as stepping in a hole can lead to dislocation of the knee if it is twisted at the same time.
What are the indications?
In most cases, the knee is evidently out of place. The knee is swollen, painful and the individual has difficulty walking.
The joint can oftentimes slip back into place on its own before a doctor can be seen but the knee stays swollen and unstable. The lower leg might feel numb and appear pale. These symptoms might indicate that an artery is impaired while the blood supply is interrupted or the nerve is damaged.
Diagnosing knee dislocations
If a knee dislocation is suspected, the individual must be taken to the nearest emergency department right away.
The doctor can identify a dislocated knee upon assessment of the joint. Nevertheless, an X-ray is taken from different angles. Unless the joint has slipped back into place on its own, an X-ray can confirm a diagnosis as well as determine the presence of any fractures.
When checking if the arteries are damaged, the doctor will check for a pulse in the lower leg usually several times over a period of time. If the arteries are not damaged, the doctor will gently move the joint to check how badly the ligaments are impaired.
Additionally, the doctor will also check for nerve damage. This is done by asking the individual to move the foot up and down as well as turning the foot in and out as well as testing for numbness.
The doctor will position the joint back in place. Prior to this procedure, the individual is given a sedative and pain medication, but he/she remains conscious. After the procedure, the knee is immobilized using a splint.
If there are damaged arteries, they are surgically repaired right away. The procedure is carried out to fix the joint and any other damaged structures.
In case the joint is very unstable, an external fixator can be applied. The device is usually a frame of rods that are affixed to the exterior of the leg by stainless steel pins inserted via the skin into the bone.