Knee ligament damage is a common injury, and can occur from a wide range of mechanisms. A ligament is a short band of connective tissue that attaches from bone to bone. Ligaments are in the joint to stop and limit mobility, this is why they are injured often due to outside forces. This can happen during a collision, a change in direction or a bad landing. When the knee is forced into a movement range that the ligament restricts, there is trouble. Usually these injuries happen at a higher speed, as the forces generated are much greater.
Knee Ligament Classifications
There are four major ligaments that stabilize the knee and we can group them into two separate groups.
- Collateral Ligaments
- Cruciate Ligaments
Check out this diagram to see exactly where the four major ligaments are.
The medial and the lateral collateral ligaments make up this group. The lateral strengthens the outer side of the knee and runs between your thigh bone and the top of your fibula. The medial ligament strengthens the knee joint on the inner side and runs between your femur and tibia. They both resist the side to side movement of the knee and prevent rotation. The lateral ligament is commonly damaged when your knee twists, or you are hit on the inner side of the knee. This is hard to occur on its own and usually happens due to outside forces.
The medial is a more common ligament to injure, and can also happen because of a direct hit to the outside of the knee or twisting of the knee.
These basically cross each other and both join your tibia to your femur. The anterior cruciate ligament runs from the front of the tibia, to the base of your femur. It stops your shin bone from moving in front of your thigh bone. A tear in the ACL is quite a common injury amongst athletes, and it can happen when you change direction rapidly, decelerate when running, landing, or from receiving a hit to the knee. This is quite a serious injury as your stability is affected greatly. Surgery is often necessary to repair it.
The posterior cruciate ligament runs from the rear of your tibia to the base of your femur. It stops your shin bone moving backwards in relation to your thigh. It is stronger than the ACL. Tearing it is less common than other ligaments of the knee, and it can occur when your knee is hyper extended, or over flexed and the shin is forced backward. This will often heal with a rehab program and an injury to the PCL alone does not usually require surgery.
Different Grades Of Knee Ligament Damage
Although different ligaments are affected differently, they are graded the same. There are three grades of injuries that will help to classify what has actually occurred to the ligament that is injured. The symptoms and treatments vary according to the different ligament that you have damaged, however this system makes it easier to grade knee ligament damage.
Grade 1: This is a mild injury, and usually the ligaments have been stretched, but not torn at all. This is not a serious injury, and you may not have a lot of pain or swelling, but left untreated and you will be predisposed to a repeat of the injury.
Grade 2: In a grade 2 injury, the specific ligament will have a partial tear. It is common to experience both swelling and bruising, and using and moving the joint through a range of motion can be quite painful.
Grade 3: A grade 3 injury is the most severe, and the ligament will be completely torn. This will cause swelling and often bleeding under the skin. You will find that your joint is very unstable and weight bearing proves very painful.
We will look at and discuss the various treatments for the different knee ligament damages in a later post.