Lateral Collateral Ligament (LCL) Anatomy and Function 

Thanks for the question. The fibular collateral ligament (FCL) and the lateral collateral ligament (LCL) are the same thing. These two terms are used interchangeably. The ligament attaches to the fibula thus "fibular collateral ligament". It is on the lateral side of the knee which is where the "lateral" comes from. "Conjoined tendon" is likely the radiologist using terminology to describe the biceps femoris (there is a "short head" and a "long head" which sort of blend together at the knee). The biceps femoris is one of the hamstring tendons that also inserts onto the the fibular head right next to the LCL/FCL attachment. It is common to injure both at the same time and I have repaired / reconstructed complete tears of this type of injury (Usually reconstruction of the ligament and repair of the ruptured biceps femoris tendon from the bone). Often the FCL/LCL and biceps femoris can actually pull off a piece of bone of the fibula with it during the injury. This is called an "avulsion". You are correct regarding sprain vs strain. The popliteus tendon is a small muscle that start/inserts along the back of the tibia and wraps around to attach on the femur near the FCL/LCL. It provides rotational stability to the knee. The combination of the FCL/LCL and the popliteus is often termed the "posterolateral corner" (PLC). In severe injuries with complete tears (not sprains or strains) the knee can have significant instability requiring surgery. PLC injuries are often combined with ACL and PCL injuries so the physician needs to do a careful clinical exam and often special X rays to accurately diagnose the injury. ___________________________________________________________________________ Please understand that this does not represent the formation of a formal doctor patient relationship and is for educational purposes only. All comments should be considered as informal suggestions regarding any matters of medical care. Please also be aware that this is a public forum and any information you share is not secure.

Good question. Actually, complete LCL tears likely do not heal on their own. If it is more of a small partial tear, that may heal but a complete tear can cause problems. MCL tears on the other hand have a high capacity to heal on their own. Not all MCL tears are the same, however. A MRI is very beneficial to make that determination before deciding on non surgical vs surgical treatment for a MCL injury. Complete ACL tears can cause instability to the knee that requires surgery in active and physiologically young patients. Older patients with less activity demands often go through a trial of rehab before deciding if surgery is needed. PCL tears can also come in varieties. Isolated, partial injuries can heal well with therapy and a special PCL brace that helps keep tension off the PCL. Complete PCL injuries and those with associated ligament injuries of the LCL or MCL often need surgery to stabilize the knee (again, in more active patients) _________________________________________________________________________ Please understand that this does not represent the formation of a formal doctor patient relationship and is for educational purposes only. All comments should be considered as informal suggestions regarding any matters of medical care. Please also be aware that this is a public forum and any information you share is not secure.

James, I'm really sorry to hear about your injury. I am unable to provide you a diagnosis just from your description. There are many potential injuries that can occur from the way you described your injury. A LCL injury is certainly one of them but even if that's the case, there are very often other associated injuries to the knee that occur at the same time. You mentioned a "scan" and a MRI scan is a very good way to help clarify the situation. An evaluation by a physician such as an orthopaedic surgeon is typically needed to appropriately figure out what is going on and determine the best treatment. I would highly encourage you to do this. Good luck! _______________________________________________________________________ Please understand that this does not represent the formation of a formal doctor patient relationship and is for educational purposes only. All comments should be considered as informal suggestions regarding any matters of medical care. Please also be aware that this is a public forum and any information you share is not secure. All patients have been consented for use of any imaging, video, or other media.

Kay, Your injury sounds quite severe. Whenever more than one ligament is torn in the knee we call it a multiple ligament knee injury (MLKI). These can cause significant disability depending on one's activity level etc. It sounds like you have seen the ortho surgeon and are set up for surgery. My advice would be to keep a close relationship with your surgeon and his /her team, ask a lot of questions, stay informed, be diligent with your physio, and take it one week at a time. Rehab is a lengthy process so don't get discouraged. You can do it! ___________________________________________________________________________ Please understand that this does not represent the formation of a formal doctor patient relationship and is for educational purposes only. All comments should be considered as informal suggestions regarding any matters of medical care. Please also be aware that this is a public forum and any information you share is not secure.

Good morning, It's a little challenging to determine exactly the source of your troubles. A few things come to mind. 1) A good physical examination will often accurately diagnose a LCL tear and resulting instability. 2) MRI is very helpful to determine acute injuries to the LCL but chronic injuries are often difficult to see on a MRI because the scar that forms and you don't have the usual "look" of a new injury on MRI to help determine the injured structure - this is where a good physical exam comes in 3) In challenging cases, special x rays called stress x rays can help determine instability from a LCL tear. This type of x ray compares the uninjured side to the injured side. 4) In patients who are bow legged (Varus), walking will cause an outward thrust to the knee. Again, special x rays that look at the whole alignment will typically help rule this in or out. 5) Uncommonly, you can in fact have instability to the fibula where it joints at the knee. This is called the proximal tib-fib joint. Again, physical exam is very helpful to confirm this. I hope this helps with some of your questions. Be sure to check in with your physician about all of this. Good luck! ______________________________________________________ Please understand that this does not represent the formation of a formal doctor patient relationship and is for educational purposes only. All comments should be considered as informal suggestions regarding any matters of medical care. Please also be aware that this is a public forum and any information you share is not secure.

One last thing... there are other injuries to the knee that can cause "locking". These include meniscal tears and cartilage injuries to the knee. A MRI is good to look for these problems.

John, I had to look up that position but according to the google images I saw, one could definitely injure their LCL. If you are worried about it, check in with an ortho surgeon. A good physical exam will likely be able to pick it up. MRI can be confirmatory. ___________________________________________________________________________ Please understand that this does not represent the formation of a formal doctor patient relationship and is for educational purposes only. All comments should be considered as informal suggestions regarding any matters of medical care. Please also be aware that this is a public forum and any information you share is not secure.

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