Knee ligaments are the tough, flexible strips of tissues that connect the bones in the knee joint. They play an important role in stabilizing the knee, and allowing the knee joint its full range of movement..
Anatomy of the Knee
There are four bones that constitute the knee joint:
- the femur (thigh bone),
- tibia (main shin bone),
- fibula (outer shin bone), and the
- patella (knee cap).
The femur and tibia are the main bones involved in the knee’s movement, and the patella sits in front of the knee joint to offer protection to the joint. At the ends of the bones, there is thick articular cartilage that helps to reduce the friction between the bones in the joint as they move. As the knee joint suffers from constant impact during running and walking, there is also a natural shock- absorber called the meniscus, which is a thick, rubbery cartilage located in between the thigh bone and the shin bone.
To help the bones in the knee joint to work properly in a coordinated fashion, there are four ligaments that hold the bones together like thick elastic bands, and stabilize them during any movement.
There are two main types of knee ligaments based on how they connect the bones to each other.
Cruciate Ligaments: These are located in the interior of the knee joint, and connect the centers of the femur and tibia in a cross like manner. There are two cruciate ligaments, and they control the back and forth motion of the knee.
- Anterior Cruciate Ligament (ACL): diagonally connects the front of the tibia to the back of the femur. This ligament controls the rotation and front-back movement of the knee. It also prevents the shin bone from moving too far forward.
- Posterior Cruciate Ligament (PCL): diagonally connects the back of the tibia to the front of the femur, crossing over the ACL. It also controls the forward and backward motion of the knee.
- Collateral Ligaments: These ligaments are located outside the knee joint on the sides, and connect the bones sideways. There are two collateral ligaments, and these stabilize the knee during any sideways movements, and limit the amount of sideways movement of the knee
- Medial Collateral Ligament (MCL): It connects the femur and the tibia on the inner side of the knee (medial). It protects the knee joint against impact directed to the outer side of the knee.
- Lateral Collateral Ligament (LCL): It connects the femur and the fibula on the outer side of the knee (lateral). It protects the knee joint against impact directed to the inside of the knee..
What are Knee Ligament Injuries?
While the ligaments are strong and fibrous tissues, they can get damaged or injured due to the below reasons:
- Direct blow to the knee
- Sharp pivoting movements
- Sudden stops or twisting at high speed.
- Awkward landing during a jump or fall
- Muscle weakness can also lead to ligament injuries
When injured, the ligament can get stretched, leading to a sprain, or it can get completely ruptured, leading to a ligament tear. Most knee ligament injuries are sprains, however athletes and high impact sports players are at higher risk for ligament tears.
The anterior cruciate ligament (ACL) is the most common knee ligament that gets injured, and it is common in sports involving sudden twisting or pivoting movements, such as basketball, skiing and football.
What are the Symptoms of Knee Ligament Injuries?
Knee ligament injuries can sometimes manifest without any symptoms, but generally the below symptoms are common:
- Pain and swelling of the knee
- Tenderness at the knee joint over the injured ligament area
- Reduced range of movement of the knee.
- The knee may feel unstable, and unable to support any weight
- The knee may pop and give away suddenly
The treatment options for injuries to knee ligaments will depend on the nature and extent of the injury and also on the specific ligament affected.
For more on knees go to this article on sore knees