by James Hubbard, MD, MPH

It’s football season and prime time for knee injuries. But truth be told, I see them all year long—in athletes and the rest of us.

They happen at home, at work, and during any recreation at any age. Sometimes they happen when you’re just standing still and twist the wrong way.

When you hurt your knee, it may be evident you’ve done major damage. Often, though, it’s not so clear. Knee-sprain symptoms can be the same as symptoms from something more serious.

Even we doctors sometimes have a tough time telling a sprain from a tear. One reason is it’s hard to try to move a swollen, painful knee.

So what can you do when no one medical is around? There are a few things, but first, it helps to know the anatomy.

An Inside Look at Your Knee

In this plastic replica of the right knee, the kneecap, muscles, and tendons have been removed. The femur (thighbone) sits on top of the tibia (big bone of the lower leg.) You can see the fibula (smaller outside bone, lower leg) has little to do with supporting your weight. Now here are the parts of the knee you’ve probably heard about being injured in sports: Between the femur and the tibia are the cushioning left (lateral) and right (medial) meniscuses, also called cartilage. The lateral collateral ligament (LCL) is brown and to the extreme left. The medial collateral ligament (MCL) is to the extreme right. The brown piece in the middle is the anterior cruciate ligament (ACL.)

The knee is a hinge joint. It uses tendons attached from muscles to bones to flex and extend your lower leg.

Ligaments connect bone to bone, and the knee has four. Without them, your knee would buckle with the least little shift in weight.

A thick cartilage, called meniscus, separates and cushions the thighbone (femur) and lower leg bone (tibia) so they won’t crunch together and wear down.

Both how you get injured and your symptoms help indicate which part of the knee you’ve damaged.

A twisting of the knee or a direct hit on the side can tear the cartilage. This can cause pain and swelling. Walking may be difficult. Sometimes the torn cartilage can twist out of position and cause your knee to lock.

Tearing a ligament usually takes more force, either with a direct hit or falling awkwardly. It, too, can cause pain and swelling, and sometimes the knee feels unstable.

In addition, with any of this trauma, you can fracture a bone. The most common fracture would be a crack in the upper tibia.

And of course, you can sprain a knee ligament, tendon, or muscle without tearing it.


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Fracture Vs. Tear Vs. Knee-Sprain Symptoms


Symptom/Sign Possible Injury
One area aches, knee feels stable, there’s no swelling. Sprain.
Knee feels unstable. Torn ligament (the stabilizing bone-to-bone connection).
Knee locks up. Torn meniscus (the cartilage cushion between your upper and lower leg bones).
Area has a lot of swelling (especially if it comes on quickly). Something serious (fracture, tear, or dislocation; probably not a sprain).
You feel a lot of pain with weight bearing, even when the leg is straight. Fracture.
Bone or joint looks distorted. Fracture, dislocation, or both.
Area looks distorted and you can’t feel a pulse in the foot. Injury to an artery. This is an emergency. Get help immediately. If that’s impossible, at least put the joint or bone back in place, or you may lose a limb. (I’ll need to do a separate post sometime to show how to do that.)

Any time you have these symptoms or the pain is bad even without weight bearing, you need to see a doctor. (See “When Should I Get to a Doctor?”)

Treatment for When There Is No Doctor
How to Stabilize a Knee

Here are four ways to stabilize a knee when you have a tear, break, or dislocation:

  1. Use a brace (preferred).
  2. Use an elastic bandage.
  3. Make a knee immobilizer with two Sam Splints, one on the outside and one on the inside of the knee. Bandage them in place with the leg straight. If you don’t have two Sam Splints, you could use sticks.
  4. Wrap the knee with a sweater or a blanket or anything that will keep it extended.

If getting to a doctor is impossible, here are some things you can do until it is possible.

1. Get off your knee. Sit or lie down where you are. The first steps with any sprain or tear are RICE (rest, ice, compression with an elastic bandage, and elevation).

Next, evaluate what may be wrong.

2. Look at the injury. If the area looks distorted, you’ve broken a bone or dislocated your knee joint, and you’re going to need to stabilize and stay off of it. Get to a doctor if at all possible.

3. Feel around the joint and the bone. If there’s one spot of exquisite tenderness there’s a good chance you’ve broken or torn something.

4. Move the knee around by flexing it and extending it. If you can’t or it hurts really badly, you’ve probably got a significant injury.

In these next steps, you’ll keep evaluating the injury but also deal with your mobility.

5. If the leg is not distorted, slowly get up to see if weight bearing hurts badly or the knee feels unstable. If it does, don’t try to walk. You’re going to need help or a makeshift crutch or cane.

6. If you’ve stabilized the knee in the straight position (per step 2) and it still hurts to bear weight, a bone may be broken. You need a crutch or crutches so you can walk without bearing weight on the injured leg. (Putting weight on it may make things worse.)

7. If it only hurts badly when you try to walk with the knee flexing, and the knee seems stable, something still may be torn. (A lot of swelling is another sign of a possible tear.) It’s not as essential, but a brace, even an ace bandage may help.

8. If you’ve stabilized the knee and it doesn’t hurt to bear weight, you may still benefit from some sort of cane. Use it in the hand of the unhurt side, swinging the hurt leg forward and bracing with the cane on the opposite side to keep your balance as you walk.

Tearing a cartilage or ligament is not in itself an emergency. Most people end up having surgery, especially if the knee is unstable or severe pain continues, but I know many who do just fine without ever succumbing to the scalpel.

What’s been your experience with knee injuries? How did you injure your knee? What were your symptoms? What was the treatment? What was the outcome?

** UPDATE: Got Questions? I’ve answered four FAQs here. **

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Photo of knee splint by Andrea Lofthouse on Flickr. Photo of plastic knee by April J. Gazmen on Flickr.