Knee Dislocation

ExitCare ImageKnee dislocation occurs when two or more linked knee bones shift out of alignment, and no longer touch. For this to happen, an injury must also occur to more than one of the four major ligaments of the knee. A ligament is soft tissue that holds bones together, across a joint. In the knee, ligaments hold the thigh bone (femur) and the shinbone (tibia) in place. When a ligament is stretched farther than it is designed to stretch, the ligament is at risk for sprain. Knee ligament sprains can be a disabling injury.

SYMPTOMS

  • One or more "pops" heard or felt, at the time of injury.

  • Inability to continue activity after injury.

  • Knee swelling, noticed within 6 hours after injury. Possibly, deformity of the knee.

  • Loss of knee motion.

  • Knee giving way or buckling. Often, swelling with repeated giving way.

  • Sometimes locking, when there is also injury to the meniscus cartilage in the knee.

  • Rarely, injury to nerves (numbness, weakness, paralysis), discoloration, or coldness (due to artery injury) of the foot and ankle.

CAUSES

Knee dislocation is the result of a force on the joint that is greater than the ligaments can withstand. This is often caused by a direct hit (trauma). It may also result from a non-contact injury (stepping in a hole in the ground, over extending the knee, twisting).

RISK INCREASES WITH:

  • Sports that involve pivoting, jumping, cutting, or changing direction (basketball, gymnastics, soccer, volleyball). Contact sports (football, rugby, lacrosse). Sports on uneven ground (cross country running, soccer).

  • Poor leg strength and flexibility.

  • Improper equipment.

PREVENTION

  • Warm up and stretch properly before activity.

  • Maintain physical fitness:

  • Thigh, leg, and knee flexibility.

  • Muscle strength and endurance.

  • Learn and use proper exercise technique.

  • Wear proper equipment (correct length of cleats for the surface).

PROGNOSIS

If treated properly, which may require surgery, knee dislocations can be healed. Returning to sports is possible, but not guaranteed. Untreated knee dislocations often result in recurring injury or instability of the knee joint.

RELATED COMPLICATIONS

  • Frequently recurring symptoms, such as knee giving way, instability, and swelling.

  • Injury to meniscal cartilage, resulting in locking and swelling of the knee.

  • Injury to other structures of the knee (bone, articular cartilage), resulting in knee arthritis.

  • Injury to other ligaments of the knee.

  • Knee stiffness (loss of knee motion).

  • Permanent injury to nerves (numbness, weakness, paralysis) or arteries.

  • Removal (amputation) of the leg, due to nerve or artery injury.

TREATMENT

Knee dislocations require immediate realigning of the bones (reduction), if they are displaced. This should be followed up with artery and nerve function tests. The knee should then be treated with ice and medicine, to reduce pain and inflammation. Walking with crutches is advised, to keep weight off the injury. Your caregiver may advise that you wear a brace, at first. Rehabilitation will be needed, to regain strength and control of knee function. A physical therapist may teach you techniques to avoid further knee injury. Surgery that is properly timed after the injury is often the best way to achieve a full recovery. Surgery involves replacement (reconstruction) of one or more of the injured ligaments. If it has been determined that you have an injury to an artery, this will also require surgery.

MEDICATION

  • If pain medicine is needed, nonsteroidal anti-inflammatory medicines (aspirin and ibuprofen), or other minor pain relievers (acetaminophen), are often advised.

  • Do not take pain medicine for 7 days before surgery.

  • Prescription pain relievers are usually prescribed only after surgery. Use only as directed and only as much as you need.

HEAT AND COLD

  • Cold treatment (icing) should be applied for 10 to 15 minutes every 2 to 3 hours for inflammation and pain, and immediately after activity that aggravates your symptoms. Use ice packs or an ice massage.

  • Heat treatment may be used before performing stretching and strengthening activities prescribed by your caregiver, physical therapist, or athletic trainer. Use a heat pack or a warm water soak.

SEEK MEDICAL CARE IF:

Any of the following occur after injury or surgery:

  • You experience pain, numbness, coldness or blue, gray, or dark discoloration in the foot or toenails.

  • You develop signs of infection: fever, increased pain, swelling, redness, drainage of fluids, or bleeding in the affected area.

  • New, unexplained symptoms develop. (Drugs used in treatment may produce side effects.)