December 21st, 2011
We all have had our fair share hearing about a famous American football player or basketball player tearing their ACL and having to quit their season. The words “ACL tear” have such a stigma attached to them, people cringe just at the sound of it. Luckily for us uphill skiers, we don’t have to worry about tearing our knee ligaments too often, but don’t rule it out.
In case some of you didn’t know, there are four major ligaments of the knee: ACL, PCL, LCL, and MCL. To help you understand why these ligaments are so important, I’ll explain them all.
ACL: The ACL, also known as the Anterior Cruciate Ligament is found in between the menisci of the knee and crosses (hence the word cruciate) with the PCL. The ACL itself is made up of three bands: the anteromedial, intermediate, and posterolateral. The ACL prevents the femur (thigh bone) from moving posteriorly (backwards) when you are putting full weight on your leg. It also limits your tibia (shin bone) from anteriorly (forward) when non weight-bearing. One of the ACLs biggest supporters is the hamstring tendon group. Commonly if someone chooses not to get a skin graft to repair their ACL, they have to go through extensive rehabilitation to regain stability of their knee. Strengthening the hamstrings is one way to help add stability to the knee again.
PCL: The PCL, or posterior cruciate ligament, isn’t often completely torn because it is stronger than the ACL. It’s main function is to help prevent hyperextension of the knee. Often times tearing of the PCL is referred to as a “dashboard” injury because people who are involved in car accidents are prone to tear their PCLs when their knees hit the dashboards of their car on impact. Be careful skiing with your knees bent going into the trees!
MCL: The MCL, or Medial Collateral Ligament, attaches on the medial (towards the center of the body) epicondyle (bony protusion) of the femur (thigh bone) to the tibia (shin bone). The MCLs main function is to stabilize the knee when in a valgus position. To explain this, imagine you just took a step forward with your right foot, and someone kicked your ankle from the inside. Your foot goes out to the right at a funny angle. Most likely the next day you will feel some soreness on the inside of your knee, which was from your MCL possibly being torn from the valgus force that was produced.
LCL: The LCL, or Lateral Collateral Ligament, can be felt the easiest out of all the ligaments. Athletic trainers will often put athletes into the “Figure 4” position to palpate the LCL. Either sitting or standing, bring your foot up and try to touch your opposite knee. Almost like you are sitting with one leg crossed. With practice, you can palpate your own LCL! The LCLs main function is to protect the knee from varus forces. (Imagine the same scenario from before, but someone kicking you from the outside, and pain presenting on the outside of the knee). Other structures that support the LCL include the IT band.
Most commonly, an injury to these ligaments occurs when the knee is forced into a position it isn’t naturally supposed to go into. The sports with high impact have this occur more often than cross country skiers do, but our relatives aren’t as lucky. Injuries to these ligaments is more common in downhill skiing because of the falls that can occur. Basically, if you can stay on your feet and are striding and gliding normally, you shouldn’t be at risk!