Knee Dislocation

Dislocation of the knee usually is caused by motor vehicle accidents, sports injuries, or falls. Dashboard injuries cause posterior dislocations (i.e., posterior translation of tibia), and hyperextension injuries cause anterior dislocations. Popliteal artery injury is common after knee dislocation and requires emergent vascular surgical consultation for repair.

Causes

Knee dislocations are rare. They usually happen only after major trauma, including falls, car crashes, and other high-speed injuries.

• The knee is dislocated, it will look deformed. The usual straight line of your leg will be crooked.
• Sometimes, knee dislocations relocate on their own. In this case, the knee will be very swollen and painful.
• The knee is a very stable joint requiring high-energy trauma to produce dislocation. At least 3 major ligaments must rupture for dislocation to occur. Common mechanisms of injury include the following:
• Motor vehicle collisions
• Auto-pedestrian impact
• Industrial injuries
• Falls
• Athletic injuries

Signs

• May be obviously dislocated or grossly unstable, which may indicate dislocation with spontaneous reduction
• Popliteal fossa may be fullowing to vascular injury or may appear normal if decompressed by capsular tear
• Diminished pulses or neurologic deficit

Treatment

If your doctor will need to properly 'reduce,' or reorient, the position of the kneecap. Early treatment of patellar subluxation includes:

• Physical Therapy with an emphasis on quadriceps strengthening, specifically the VMO muscle group as described above.
• Bracing and Taping- Special knee braces are designed to control the motion of the patella.
• Better Footwear - Motion control running shoes may control your gait while running and decrease the pressure on the kneecap.

Surgical treatment:

• Perform before weight bearing
• Ant-medial approach
• Inverted V in rectus femoris or tongue flap
• Medial and lateral parapatellar incision
• Free fibrosed quads, patella and tendons from bone
• Possible release anterior knee capsule, IT band and lateral septum