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Knee Anatomy

The knee is a complex joint that consists of bone, cartilage, ligaments, and tendons that help in your joint’s movements.

The knee is a hinge joint made up of two bones, the thighbone (femur) and shinbone (tibia). Ligaments are tough bands of tissue that connect one bone to another bone. The ligaments of the knee stabilize the knee joint. There are two important groups of ligaments that hold the bones of the knee joint together, cruciate and collateral ligaments.

Cruciate ligaments of the knee joint:

  • Anterior Cruciate Ligaments (ACL)
  • Posterior Cruciate Ligaments (PCL)

Collateral ligaments of the knee joint:

  • Medial Collateral Ligament (MCL)
  • Lateral Collateral Ligament (LCL)

Symptoms of Knee Ligament Injuries

The symptoms vary with the severity of the injury. They include:

  • A loud popping sound occurring during injury
  • Knee swelling
  • A feeling of looseness in the knee joint
  • Knee pain that may be sudden and severe
  • Pain with weight bearing on the injured knee

Types of Knee Ligament Injuries

ACL Injury or Tear

An ACL injury is a sports-related injury that occurs when the knee is forcefully twisted or hyperextended. An ACL tear usually occurs with an abrupt directional change with the foot fixed on the ground or when the deceleration force crosses the knee. Changing direction rapidly, stopping suddenly, slowing down while running, landing from a jump incorrectly, and direct contact or collision, such as a football tackle, can also cause injury to the ACL.

PCL Injury or Tear

PCL injuries are very rare and are more difficult to detect when compared to the other knee ligament injuries. Cartilage injuries, bone bruises, and ligament injuries often occur in combination with PCL injuries.

Injuries to the PCL can be graded as I, II or III depending on the severity of the injury. In grade I, the ligament is mildly damaged and slightly stretched, but the knee joint is stable. In grade II, there is a partial tear of the ligament. In grade III, there is a complete tear of the ligament and the ligament is divided into two halves, making the joint unstable.

The PCL is usually injured by a direct impact, such as in an automobile accident when the bent knee forcefully strikes the dashboard. In sports, it can occur when you fall to the ground with a bent knee. Twisting injury or overextending the knee can cause the PCL to tear.

MCL Injury or Tear

The MCL is the ligament that is located on the inner part of the knee joint. It runs from the femur (thighbone) to the top of the tibia (shinbone) and helps in stabilizing the knee. MCL injuries can result in a stretch, partial tear or complete tear of the ligament. Injuries to the MCL commonly occur because of pressure or stress on the outside section of the knee.

LCL Injury or Tear

The LCL ligament is located on the outer part of the knee joint. It runs from the femur (thighbone) to the fibula (the smaller bone in the lower leg). The LCL helps in stabilizing the knee against unusual movement. LCL injuries can result in a stretch, partial tear or complete tear of the ligament. Injuries to the LCL commonly occur because of pressure or stress on the inside section of the knee.

Treatment of Knee Ligament Injuries

It is important to seek your doctor’s advice if you hear a popping noise or feel as if your knee has given way at the time of injury and if you are unable to move your knee because of severe pain.

Your doctor will suggest various non-surgical methods to treat knee ligament injuries. Surgery is an option if you do not respond to conservative treatment measures.

Immediately following a knee injury, before being evaluated by a doctor, you can initiate the R.I.C.E. method of treatment:

  • Rest: Rest the knee, as more damage could result from pressure on the injury.
  • Ice: Ice packs can be applied to the injured area to reduce swelling and pain. Never place ice directly over the skin. Ice should be wrapped in a towel and applied to the affected area for 15-20 minutes, four times a day for several days.
  • Compression: Wrapping the knee with an elastic bandage or compression stocking can help minimize the swelling and support your knee.
  • Elevation: Elevating the knee above the heart level will also help reduce swelling and pain.

Non-Surgical Treatment

You may respond to non-surgical treatment and recover from the injury if the damage occurs to the collateral ligaments on the outside and inside of your knee.

Icepacks may be used every 3-4 hours to reduce pain and swelling.

Stabilize your knee joint with a compression bandage and wearing a brace.

Your doctors may prescribe medications to reduce pain and swelling.

Strengthening exercises are necessary to stabilize your joint. Your physiotherapist will plan the types of exercise based on the severity of your injury.

Surgical Treatment

Damaged cruciate ligaments will need surgery. Usually, reconstruction surgery is performed. A diagnostic arthroscopy is performed by your surgeon to view the injured parts. A graft tissue is used from your body or a donor to perform the reconstruction.

Post-operative Rehabilitation

Post-surgery rehabilitation involves the immobility of the joint for about 3 weeks. Partial weight bearing exercises may be started early with the weight gradually increased. A physiotherapist will plan your exercise strategy. Complete recovery and return to usual activities may take up to 9 months.

Prevention of Knee Ligament Injuries

Injuries to the knee are common in sports. The stability of the knee joint is completely dependent on the ligaments and the muscles. People involved in sports may prevent knee injuries by following these simple measures:

  • Practice strengthening exercises to improve knee stability.
  • Always maintain good flexibility of your legs with stretching exercises.
  • Slowly increase the intensity of your workouts as excess stress may damage the knee ligaments.

Doctors Performing Knee Ligament Injury Care