Ligament Injuries of the Knee

Knee injuries are common, especially when taking part in physically strenuous activities or sports. Injuries to the soft tissues, such as ligaments, cartilage and tendons are the most likely.

Pain and instability from knee ligament injuries can substantially reduce the joint’s range of motion, making movements like walking or taking stairs painful and even impossible sometimes. One major cause of concern is the loss of neuromuscular control, preventing muscles from working in coordination to stabilise the knee.

Types of Knee Ligament Injuries

Your knee ligaments help to keep your knee stable by holding the bones together. You have two sets of ligaments in your knee. The collateral ligaments run down either side of your knee, while the cruciate ligaments lie inside your knee. Either one of them can get damaged.

  • Collateral ligament injuries – The medial collateral (MCL) is on the inner side of your knee and the lateral collateral ligament (LCL) is on the outer side. They limit the amount your knee can move from side to side. You can sprain or tear your MCL if your lower leg gets forced outwards. Both ligaments may also be damaged if your knee twists too far outwards.
  • Cruciate ligament injuries – Cruciate means cross-shaped. Your anterior cruciate ligament (ACL) and posterior cruciate ligament (PCL) form a cross inside your knee. They help to keep your knee stable by controlling its movement backward and forward. ACL injuries are one of the most serious types of knee injury. They often happen when you twist your knee, for instance when you land on your leg, then quickly turn. People who play football or basketball are usually the ones who suffer this type of injury the most. Your PCL may get damaged if you fall on your knee while it’s bent. Another typical way of damaging the PCL is when your knees hit a hard surface in front of you during a car accident.

If you’ve injured one or more of your knee ligaments, a doctor will investigate and will categorize your injury according to the extent of the damage.

  • Grade 1 is a stretch of the ligament without tearing.
  • Grade 2 is a partial tear of the ligament.
  • Grade 3 is a complete tear through the ligament.

The knee ligaments that you’re most likely to damage are your MCL and your ACL. The other structures that can be injured are medial and lateral meniscus (These are the shock absorbers/washers in the knee. They can cause sharp pain/locking of the knee and stiffness in the knee.)