One day you felt a click or pop in your knee.  A few days later you can barely walk.  You are usually between 45 and 75 years of age.  After kneeling down, or squatting to pick something up you felt a pop inside your knee. You have some pain in the knee, but immediately after the pop it wasn’t terrible pain. The next day the pain is worse, and the pain on the inner part of your knee continues to worsen to the point that you can not walk.  Now your knee starts to swell.  Why has the pain on the inside of your knee worsened over the last few days?

Although not described as a terrible triad in the scientific literature, over my 20 years of experience I have heard this story enough to know what the list of diagnoses will be in this situation after talking with you for a few minutes. This is a very common cause of medial knee pain, or pain on the inner side of your knee in people between 45-75 years of age.

Your MRI will often show a:

Those three findings on your MRI are related to one another… one caused the next to occur and so on.  This is what I refer to as the Terrible Triad of (medial) knee pain. It is often over-treated, under-recognized and poorly understood by patients I see for second opinions.

The Terrible Triad: Part I – Meniscus Root Tear

function of the meniscusThe meniscus plays a very important role as a cushion inside the knee.  It distributes the stresses of walking very efficiently.  A meniscus root is where the meniscus is actually attached to the bone.  The meniscal root attachment degenerates (or wears out) in our knee just like many other tissues in our body.  That’s why it will pop while simply squatting down or twisting while walking.  That was the straw that broke the camel’s back.  This post goes into more detail about root tears of the medial meniscus.  

The Terrible Triad: Part II- Osteoarthritis of the knee

knee arthritisThe degeneration of the meniscus root causes it to “tear”.  When the tear occurs the function of the meniscus is lost. That loss of cushioning function causes an increase in stress on the bone.  In the terrible triad you also have osteoarthritis.  Osteoarthritis of the knee implies that you have lost some of the articular cartilage which covers the ends of the bones in the knee.  That cartilage also cushions the knee.

The Terrible Triad: Part III- Insufficiency fracture

So… if you tear the root of the meniscus the stress in the knee increases.  You already have arthritis so the cartilage cushion was thin and less protective.  All of this causes an increase in the stress within the bones in the knee.  In many of you that will lead to a stress fracture or an insufficiency fracture.  Those insufficiency fractures of the knee cause a ton of inflammation which shows up on an MRI as bone marrow edema.  It takes 1-3 days or more for the stress fracture to occur following a root tear. That’s why the pain worsens over the next few days after you felt the pop.

The bone marrow edema caused by the insufficiency fracture causes severe pain.  The meniscus is not the most likely cause of pain in this situation.  Bone is a confined space, it can not expand.  If you have inflammation and swelling in the bone then the pressure in the bone will increase.  That’s why an infected tooth hurts so much… that infection is confined to a tight space, so the pressure rises and it is the pressure that hurts so much.

The terrible triad hurts a lot.  That usually leads to a visit to your doctor or an Orthopedic Surgeon.  An MRI is obtained and the findings I mentioned earlier are identified.

Treatment of The Terrible Triad of Medial Knee Pain

Most of you who have all three of the findings I mentioned above will usually have very severe pain.  For some of you, your Doctor will focus only on the meniscus and recommend surgery to remove the torn meniscus. That is not recommended as the best way to proceed if you have a degenerative root tear in the presence of osteoarthritis and bone marrow edema. If your doctor recommends surgery to “clean out” the knee, again the research shows that the surgery often fails to alleviate your pain, and increases your risk of needing a knee replacement.

It is often the bone marrow edema from the stress reaction or insufficiency fracture which is causing your pain.  Usually time and limiting weight bearing can improve that pain.  It can take 1-3 months for the pain to subside. A subchondroplasty for bone marrow edema can help a limited number of people feel better.  In a knee with mild arthritis and persistent pain then a root repair (not removal of the torn piece) in combination with a subchondroplasty might be and an option to discuss with your doctor.  Make sure that your Orthopedic Surgeon knows how to perform meniscus root repairs.  They are not easy to perform, and most surgeons still remove these torn pieces.  Focusing on meniscus preservation and repair will offer your the best chance of long term success.

If the arthritis is moderate to severe and your pain persists despite rest, and limited weight bearing, then a knee replacement might prove to be your best option.

Bottom line is that treatment recommendations need to be individualized to improve your chance of success, and minimize the risk of worsening arthritis or the risk of having an unnecessary surgery.

Disclaimer

About the author:

Howard J. Luks, MD

A Board Certified Orthopedic Surgeon in Hawthorne, NY. Dr Luks specializes in the treatment of the shoulder, knee, elbow, and ankle. He has a very "social" patient centric approach and believes that the more you understand about your issue, the more informed your decisions will be. Ultimately your treatments and his recommendations will be based on proper communications, proper understanding, and shared decision-making principles --- all geared to improve your quality of life. Please read our Disclaimer

19 comments on “Severe Medial Knee Pain Explained: The Terrible Triad

  1. This was so helpful, my knee pain is so severe. Your symptom checker convinced me to see my Dr., I have OA. & Had spinal, & cervical fusions. Metal plates & screws.

  2. How bad are stairs in a home with these knee conditions (age 68)? I am thinking of buying a stair lift, as advertised on tv, to ride up the stairs. I am concerned that the moderate osteoarthritis and meniscus tear will be exacerbated by the stairs. Thanks!!

    1. Without examining someone or assessing their abilities I can not tell you if that purchase is worthwhile or not.

  3. Good Morning Dr. Luks,
    Thanks for your excellent articles. Surgeon wants to do surgery to repair/remove partial meniscus. Previous meniscus repair in USMC. Pain has worsened over past 6 months. Biggest complaint is sleeping or lack thereof. From reading your articles my concern is the marrow edema. Any recommendations? Do you recommend a second opinion? X-Ray shows moderate osteoarthritis, MRI comments below. About 25-30 pounds overweight. Thank You.
    Findings: Osteophyte formation and cartilage loss are identified in
    the medial compartment. There are several large defects in the
    articular cartilage of the medial femoral condyle with marrow edema in
    the medial tibial plateau. Abnormal signal within the posterior horn
    of the medial meniscus extends to the inferior articular surface on
    series 3 images 9-10. It also extends into the meniscal body. The
    lateral meniscus is unremarkable.

    1. Definitely seek a second opinion… you have a highly degenerative knee. A straightforward arthroscopy is not usually successful in the long term in these instances.

      It would depend on your exam … but you might be correct. Bone marrow edema is often the cause of pain, and an arthroscopy will not address that since it is due to the arthritic changes.
      Good Luck

  4. Aloha Dr. Luks,
    I am 67 and have run for over 30 years. Three years ago a surgeon said I needed a knee replacement. I didn’t have it and now have a new problem. I had an X-ray, then an MRI of my left knee. I went back to the surgeon who told me I had a bruised bone? The MRI showed some subchondral degenerative signal in the distal femur. Also small partial-thickness cartilage fissure, Tear of the free margin of the mid body of the medial meniscus. Indistinct tear versus meniscal contusion at the junction of the mid body and posterior horn of the medial meniscus. The surgeon said I didn’t have a tear? Why would the MRI findings say other? Thank you in advance for your very informative website, and all your help!!
    Sincerely,
    Sue Hahn

    1. HI Sue…
      THose degenerative tears are rarely a problem and often do not respond well to surgery. There is also a fairly high risk of becoming worse after meniscus surgery in a degenerative knee. Sometimes if docs use the term bruised bone they mean bone marrow edema. I also elaborate on it further on this post. That may or may NOT be the source of your pain… I can only tell after a good examination.

  5. The pain described in the beginning of this article almost exactly described what I have experienced. The only exception being instead of a initial click or pop in the knee it was more of a feeling of a bad cramp in the back of the knee that would not go away. After this the next day the knee pain was worse, swelling followed and the pain moved to the inside of the knee. I have dealt with it in the hopes that it would eventually heal itself but it has been difficult. Just curious how often you have heard the initial pain described as a cramp like feeling.
    Thanks for the information, greatly appreciated.

    1. HI John…
      I have heard patients describe the initial event in many different ways. A good exam and perhaps an Xray and MRI will tell you if the root of the meniscus is torn, and if there is bone marrow edema (inflammation) present.

      Good luck !

  6. Sure appreciate your article and your responses to the comments. Also appreciate your philosophy about educating patients so that they can actively participate in decisions about their health care… wish more medical providers felt same way :>) Thank you!

  7. Dr. Howard J. Luke, can’t thank you enough for sharing such excellent professional information and opinions which one must pay lots of money for in our time. You make me feel there’s still hope in humanity.

  8. I had surgery for 2 meniscus tears on August 17th. It was awesome for the first two weeks. I tripped and fell directly on top of the knee that had the surgery. Now I cannot walk without a limp and severe pain. I have had a cortisone shot and 4 weeks of physical therapy. The swelling will not go down and the pain will not ease up. I have a snap on the inside of the knee that is constant and sharp pain. I was given a different antiinflammotory shot today and told to give it 4 weeks. I was told an MRI would be a waste because it is so swollen and so soon after surgery.

    1. Sounds like a new MRI might be a good idea. Swelling in the knee might actually highlight the important structures better.

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