Knee Pain Causes

Knee pain causes — what are they? In this article, Knee Doctor J. Michael Bennett, MD, discusses knee anatomy and the symptoms and causes of knee pain.  Dr. Bennett is regarded by his peers as one of the best orthopedic surgeons and sports medicine specialists in Metro Houston TX.  He was recently named to the Texas Super Doctors® List based on recommendations from other orthopedic surgeons and physicians in the Houston, Katy and Sugar Land areas.

Doctor J. Michael Bennett is a Board Certified Orthopedic Surgeon and a Fellowship Trained Sports Medicine Physician with a Certificate of Added Qualification (CAQ) in Sports Medicine. For an appointment at our Sugar Land office please call 281-633-8600, and for an appointment at our Houston office please call 713-234-3152.

In this video, Doctor Bennett discusses the anatomy of the knee and some of the main knee pain causes; including meniscus tears, anterior cruciate ligament injuries and patellofemoral pain syndrome.

This information is for educational purposes only.  It’s not intended as a substitute for professional medical advice, diagnosis, or treatment.  You should not act upon any information provided here without first seeking medical advice from a physician.

Summary of the Knee Pain Causes Video

Hello, my name is Dr. J. Michael Bennett. I am an orthopedic surgeon and specialist in sports medicine.  My specialties include minimally invasive surgery and arthroscopic surgery of the shoulder, elbow, and knee.  I’m CAQ (Certificate of Added Qualification) certified in sports medicine, and I’m with the Fondren Orthopedic Group.

Today we’re going to talk about knee pain, particularly knee pain in younger patients or younger individuals with arthritic issues or even older active patients who have knee pain.  I want to go over what the knee looks like and what common symptoms are associated with knee pain and how you can determine the real causes of knee pain based on the types of symptoms that you’re experiencing.

Anatomy of the Knee

[Referring to the knee model]  So first off starting with the anatomy, this is a knee model.  The standard knee is stabilized by four ligaments — you have a medial collateral ligament on the inside of the knee, you have a lateral collateral ligament on the outside of the knee, and they give you stability with what we call varus and valgus stress.  That means stressing from side to side on the knee. 

In the central portion of the knee, you have two ligaments that are called the cruciates — they are the anterior cruciate ligament and the posterior cruciate ligament.  They crisscross each other in the middle of the knee and these give you stability with rotation as well as with anterior and posterior stability.

Knee Pain Causes – Ligament Injuries

The anterior cruciate ligament is the one you hear about and read about.  It’s the most commonly injured ligament that we see, particularly in high contact or full contact sports.  Another ligament which is commonly injured is the medial collateral ligament, which is here on the inside of the knee.

Knee Pain Causes — Meniscus & Cartilage Injuries

Within the knee itself, this yellow portion of the knee is bone and this blue portion is cartilage, and these two discs within the knee are also cartilage, but they are a different type of cartilage.  They’re actually more of a softer cushion type of cartilage, which makes them a little more mobile than this type of cartilage here, lining the bone.  These are called meniscus.  You have one on the inside of the knee and one on the outside of the knee.  They are disc shaped and you can see the difference in their sizes.

This is a very common area to be injured, particularly in high impact athletes, runners, and patients that do a lot of twisting and turning activities.  But I’ve had patients who’ve injured their meniscus just by bending down and picking their children up.  It depends on the patients and it depends on their predisposing type of anatomy, to determine who gets a meniscus tear and who doesn’t.  It also depends on the mechanism of injury.

Typically if you’re running or you’re doing your activities, if you feel any painful locking sensation or catching sensation with the knee, particularly with a twist or turn or cut, often times this can mean that you have a cartilage injury in the knee.  Most often this is a meniscus tear.  Now this needs to be verified with an orthopedic surgeon, who also needs to do an exam and often times get an MRI to correlate with this.  But the symptoms are very much classic symptoms that are associated with meniscus tears.  Usually the patient will come in and describe their pain on one side of the knee or the other.  It’s not in the front of the knee, it’s usually on the inside of the knee or the outside of the knee, right along the joint line.  They can usually pinpoint where the pain is, and often times they’ll say, sometimes the pain is there and sometimes it’s not.  It’s usually exacerbated with this activity or that activity and I first noticed it when I was playing basketball with my friends, I did a twisting movement and I felt a pop.

Now it’s important that the orthopedic surgeon evaluate you because you need to make sure that you don’t have a ligament injury as well as a meniscus injury.  But if your knee feels stable and if it doesn’t feel like it’s sliding on you, but it does catch and it does hurt when you twist or turn, then more than likely it might be a meniscus injury.

ACL Injuries as Causes of Knee Pain

Now that same patient that felt a pop while they were playing basketball and doing twisting mechanism, may describe it as, “my knee gave out and ever since then I don’t feel I can put weight on it because it feels unstable.”  That may be an anterior cruciate ligament injury or ACL injury and that, once again, needs to be evaluated by an orthopedic surgeon who can confirm this.  Because if it is an ACL injury, the one test we do is called Lachmans Test — we flex the knee at about 30 to 45 degrees of flexion, and actually stress the knee joint.  And if you have significant laxity with the knee on this exam, it tells us that the anterior cruciate ligament is disrupted or injured.  Usually you compare it to the opposite side because some patients have a little bit more lax ligaments than others.  So if it is definitely different on one side compared to the other and you have significant swelling of the knee, and the patient describes that sense of instability, then it’s probably an ACL and an MRI is indicated to confirm this.

In addition, we usually like to evaluate for the meniscus tear and when we do that, we usually see if the patient has pain on the joint line where this disc is located, and then we do a McMurray’s Test where we rotate the knee and see if that disc is caught with rotation.  If that little flap of the disc is caught in the joint, it will cause pain in that position and that will confirm our suspicions about the meniscus tear.

Knee Pain Causes — Patellofemoral Pain Syndrome

Now other types of knee pain that you might experience — one very common type of knee pain is called patellofemoral pain syndrome, which is also known as anterior knee pain.  It’s commonly seen in runners and we also see it in patients, that for whatever reason have a weaker vastus medialis, which is the inner aspect of the quad.  If the inner aspect of the quad is weak, the kneecap starts to drift a little.  The quadriceps is four muscles that all insert right on top of the kneecap to help stabilize the kneecap and keep it within this groove here.  If one of those muscles is imbalanced or if one of those muscles is weak, the other muscles override that muscle.  Typically it’s the largest muscle which is the VMO, vastus medialis oblique, which is this inner quad muscle.  If that quad muscle is weak, the kneecap likes to drift out, and it starts rubbing up against this condyle on the outside here.  It will bother you when you do stairs, when you squat and kneel, when you do an excess of jumping or running.  Some patients describe it as a tightness sensation.  Some patients will say they feel popping and clicking as they stand up from a seated position.  And that just means that this kneecap is rubbing up against this outside area and irritating the cartilage, and that’s called patellofemoral pain syndrome.

The good news is that the majority of these are treated non-operatively — treated with balancing the muscles out, building up the vastus medialis or inner quad muscle, and getting in a good stretching regimen.  So that’s anterior knee pain or patellofemoral syndrome.

If you have any questions or comments, please feel free to visit my website,, or feel free to call my office at 281-633-8600.  Thank you!

Don’t Ignore Your Knee Pain

There are many knee pain causes and you should seek the help of an orthopedic surgeon or sports medicine physician when you experience knee pain that is severe or that lasts more than a few days.  Dr. J. Michael Bennett is a knee specialist and he’s very familiar with the range of knee pain causes and treatments.  Call our Sugar Land office at 281-633-8600 or our Houston office at 713-234-3152 today!

Dr. J. Michael Bennett

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