What Causes Knee Pain?

Here’s 3 common knee pain causes and strategies for relief, because there’s no one answer to what causes knee pain. Knees are not only the largest joints in the human body, but also the most easily injured.

In fact knee pain is one of the most common complaints doctors hear. And that’s because the joint is actually made up of several components, all susceptible to pain and injury.

diaphragm of the parts of knee joints that can cause pain

Why Does My Knee Hurt?

The joint itself requires require multiple supporting muscles and tendons to operate smoothly.  So your own pain, soreness, stiffness, or immobility could be caused by injury, or wear to any one of these several components.

The components needed to make a knee operate properly and smoothly:

  1. Bones.  3 different bones meet to make up your knee joint. The thighbone, shinbone, and kneecap. The femur, tibia, and patella- respectively.
  2. Cartilage.  To keep the femur and tibia ends from making contact and rubbing together, the ends of both leg bones and the back of the knee cap are covered with a slippery cartilage. As long as the cartilage stays present and healthy we can expect the bones to slide smoothly over one another as we bend and twist our knees.
  3. Meniscus.  There are two wedge shaped pieces of cartilage between the femur and tibia that absorb the shock. The meniscus cartilage is different in that it is more rubbery and tougher than the articular cartilage covering the ends of the bones. When you tear, or hear of someone tearing cartilage in their knees, it’s torn meniscus.
  4. Ligaments.  Ligaments are the material that connect bones to bones somewhat like ropes lashing the femur and tibia together. There are 2 different ligaments making up a knee joint. The Collateral ligaments are for sideways motion, and the Cruciate ligaments control the back and forth movement.
  5. Tendons.  Tendons connect muscles to bones. There are quadricep tendons on the front side from the thigh to the kneecap and a patellar tendon that joins the kneecap to the shin.
  6.  Muscles. Several muscle groups are necessary for a mobile knee joint. There’s the quadriceps which are a set of 4 muscles on the front of your thigh, the calf muscle, and the hamstrings which are 3 muscles in the back of your thigh.

Looking at all the different elements that make up a knee and keep it in motion makes it easy to see that there’s a lot of areas that can cause knee pain.

3 Common Conditions That Cause Knee Pain

(1) Osteoarthritis

You can see from this image how osteoarthritis is the wearing away of cartilage that leaves bone exposed to rub on bone.

Osteoarthritis is the most common cause of chronic pain of the joints, especially knees. The cartilage degeneration sets you up for pain and inflammation caused from normal wear and tear or injury. The main symptoms of OA are:

  • Pain and soreness. Pain can be either as you use and move your knees or after you sit down.
  • Stiffness. Stiffness is usually noticed after waking up from a nights sleep, or even after sitting for long periods of time.
  • Tenderness. Arthritic joints and surrounding muscles can feel tender to the touch.
  • Loss of full range of motion. Losing the full range of motion of knee joints is common to osteoarthritis sufferers.
  • Feeling or hearing a grating sensation when moved. You can hear or feel a grating and or popping sensation when moving the joint.
  • Bone Spurs. Bone spurs are lumps or bumps that form on and around the knee joint.  Bone spurs can make it difficult to move your knee without pain, or may go completely undetected without an x ray.

What Causes Osteoarthritis

There are four main causes of Osteoarthritis in knees or any other joints:

∙ Normal Use

The simple truth is that age is a risk factor when it comes to OA. Normal use of your body can cause cartilage to wear out, break down, and degenerate over time as we age. This is probably the most common cause of Osteoarthritis, as over 20% of the US population over 6o are suffering with arthritis in one form or the other.

∙ Injury

Fractures, surgeries, or tears in the ligaments are know to lead to osteoarthritis of the knees. Athletes, professional, or hobbyist, often damage joints, muscles, tendons, ligaments, cartilage, and tear the meniscus, repeatedly — which leads to arthritis.

∙ Obesity

In the US we are in an obesity crisis! Our knees and hips are not designed to carry what has become the normal weight. The excess strain and stress on these joints causes the cartilage to break down and wear away prematurely, leaving us with OA and inflammation in the joints.

∙ Genes

There are several genetic traits to make a person more susceptible to OA. In fact it can occur in a person’s 20s and cause an untimely breakdown of cartilage in joints.

What You Can Do for Osteoarthritis of the Knee

So, Osteoarthritis is the wearing away and disappearance of cartilage on the ends of the femur and tibia bones.

The bad news is that cartilage has no blood supply, so that it has no way to repair itself. Once it’s gone, it’s gone.

However, there are definite methods to continue on with life with OA in your knees.

∙ Lose Weight

We really take our bodies for granted! When you stop to think about it, you know your knees were designed to carry the weight you were designed to weigh. Each of us has a perfect weight based on age, height, body frame, and gender.  No matter what you weigh now, every pound you can lose will substantially decrease the pressure on your knees and supporting muscles.

Not sure about your perfect weight? See if you need to lose weight with this ideal weight calculator.

∙ Regular Exercise

It certainly seems counterproductive to walk on sore knees. But, the number one remedy for pain from Osteoarthritis in the knees is exercise. The reason is simple: When you exercise you strengthen all the muscles supporting the knee joint itself. Exercise also tends to increase synovial fluid in a the joint that reduces friction during motion.

Walking for 30 minutes a day 4-5 times a week can strengthen your knees and all muscles supporting them, keep them flexible, increase joint lubrication, and decrease pain.

∙ Wear Knee Sleeves

To tell you the truth I was surprised at the difference a knee sleeve made for my bad knee. Compression Knee Sleeves increase blood flow to the joint and surrounding muscles, which provides heat to help with pain and range of motion.

Whether you’re making a trip to the mall, or getting in your regular walking activities, a good knee sleeve for arthritis will add the additional support to muscles and the joint itself to substantially increase your confidence and sense of balance.

∙ Pain Relievers

Common over the counter pain relievers and anti inflammatory drugs such as Tylenol, Advil, and Aleve are the most common go to medicines for arthritis. These may provide the relief you want, however there are definite side effects from each of these.

You should find yourself depending on them for more than a few days, see a physician. Doctors can take a closer look to determine the cause of your pain, and prescribe drugs to manage the inflammation in your knee.

∙ Supplements for Knee Pain

Glucosamine and Chondroitin are two natural ingredients known to give many people relief from joint pain. You can find these as separate items or a combination of the two places like Walmat, Walgreens, and others.

However, unless you’re taking supplements for knee pain, you’re not likely to find any real pain relief. On the other hand these supplements are designed for knee pain relief and supports everything connected with the joint.

(2) ACL Injuries

ACL is the more common terminology for Anterior Cruciate Ligament, and people who play soccer, basketball, and football are all too familiar with the ACL injuries and tears. In fact ACL ligament injuries are one of the most common knee injuries and effect athletes more than anyone.

As you can see from the acl injury diagram image above, there are two ligaments inside a knee joint that cross each other diagonally to make an X. They are in the middle of the joint and serve to prevent the lower leg bone (Tibia) from sliding forward and away from the upper bone (femur.  The Anterior Cruciate Ligament (ACL) is the one in the front, and close to half of these injuries come with meniscus, and articular cartilage damage also.

ACL Injuries in Sports

ACL injuries including tears and sprains are more prevalent with soccer, football, and basketball due to the excessive and quick maneuvers such as:

  • Cutting
  • Sidestepping
  • Pivoting from side to side

I don’t know if ACL injuries are more common than 50 years ago, but I am sure there are more due to more people of all ages engaging in sports today. Not only that, but athletes are bigger and faster today than ever before which makes it easier to tear ligaments.

What Causes ACL Sports Injuries?

  • Sudden slowing while changing direction
  • Making sudden stops
  • Having one foot planted and pivoting hard from side to side
  • Landing from a jump
  • Direct blows to a knee

Symptoms Include:

Loud popping noise or sensation. In fact you may be surprised at the volume of the pop.

  • The pain will be severe either immediately or within a few hours, especially when you try to put weight on it
  • Swelling
  • Range of motion is severely limited
  • Instability, loss of balance and stableness

Treatment for ACL Injuries

See a physician immediately! Medical professionals will determine how severe the injury is and the next step. Just because you have ACL ruptures doesn’t mean you will need invasive surgeries of any kind, but only medical people can decide.

 3 types of ACL injuries and probable treatments:

  1. Sprain. This is when the ligament stays completely intact with a stable knee joint. The ligament will be stretched and have small tears in it. An acl injury grade 1 usually doesn’t require surgery, but rest and probably some sort of therapy.
  2. Sprain with tearing and separation. This is when there is a definite tear in the ligament, but the tear is not a complete separation like the image above. This type of tearing may or may not require surgery, but definite acl injury rehabilitation and rest either way.
  3. Complete tears. This is a total separation and rupture of the ACL ligament and requires surgery in most instances.

7 prevention methods and techniques for avoiding painful sports related knee injuries.

  1. Don’t play without warming up. Warm muscles, joints, tendons, and ligaments are much less likely to sustain injuries than cold ones.
  2. Stretches. Make stretches part of your warm up exercises and include thighs, calves, and your hips.
  3. Get Strong. The stronger your legs, calves, and hips are the more your knees can withstand the sudden movements and twisting motions that causes knee pain and injuries.  Do squats, lunges, and build core strength.
  4. Practice quick direction changes. Practice running to a particular spot like a line or cone and quickly changing directions by planting your outside foot and not letting the that knee collapse as you change direction. Practice running diagonal and front to back patterns and maintaining good body position. Practicing technique that involves keeping your hips over your knees and ankles will help you avoid injury.
  5. Take a break. Rest is an essential component of any exercise, sports, or physical activity that requires a lot exertion. Ensuring that you have rest days will always give your body a chance to mend itself, build new and stronger muscles, and generally aid in avoiding injury.
  6. Practice your balance. Did you know that many sports related knee damage starts with simply being off balance? No matter how good you think your balance might be, you can always improve it with practice. Make a habit of doing things like standing on one leg, standing on one leg while reaching for the floor, juggling a soccer ball in the air with one foot, and reading this post on balance exercises for seniors.
  7. Practice Jumps. Spending time jumping will definitely help. Practice jumps that include side to side with feet together and with feet apart about the width of your shoulders. Jump forwards and backwards, and change directions while in the air. When you practice remember you are building form and technique so never let your knees turn in.
  8. Bonus. Even though research indicates that wearing a acl knee brace or knee sleeve doesn’t do much for prevention, there are plenty of people who would argue the point. Knee sleeves help with being aware of where your knee is at all times, adds support to the joint and surrounding muscles, and warms the joint by increasing the blood flow. All of these knee sleeve benefits can help you avoid knee injuries, knee pain, and soreness.

To prevent ACL problems and avoid knee knee pain, being aware of your body, body and especially leg and thigh strength, and good balance are the keys. Lean to keep your knees directly over your ankles and feet, and never let your knees collapse to the inside. Make stretches, warm ups, drills, and strength part of your lifestyle.

(3) Meniscus Tears

To tell you the truth — there’s a lot of “most common knee injuries”, and Meniscus tears is certainly one of them.

Each knee joint comes with two menisci to work as cushioning between the thigh bone and shin bone. The two are referred to as meniscus and are somewhat different than the cartilage on the end of the femur, or thigh bone.

Each of the menisci are C shaped, thicker, and more rubbery and tougher than the articular cartilage.  They absorb the shock coming up from landing your feet as you move, walk, run, jump, etc. Looking at the image below you can see that they have a ridge around the outside of the C which is to help stabilize the knee and keep the joint in place.

What Causes Meniscus Tears?

  • These tears most often occur with a forceful twist and rotation movement of a knee while all your weight is on it.  When you consider that, it’s easy to see why athletes playing contact sports are at the highest risk for Meniscus tears. However, these knee injuries don’t have to be on the playing field, and can happen at any age.
  • All cartilage wears and degenerates as we age, so that includes the menisci.  As they begin to wear thin with age they can weaken and be more prone to tears.  Senior citizens can often tear a meniscus with only a sudden or cumbersome twist when getting up or down.

More often than not, anytime you hear about someone with a torn cartilage in their knee, it’s a torn meniscus.

Symptoms of a Meniscus Tear

You might feel a “pop” when you tear a meniscus, or feel nothing at all for a few hours. . Most people can still walk after this injury.  In fact, many athletes keep playing with a torn or injured meniscus.

Even if you are not aware of the damage when it actually occurs, over the next 2 to 3 days, your knee will gradually become more stiff and swollen.

In either case, like all knee injuries, the most important thing to do is see a physician. Only a qualified medical professional can properly evaluate the situation and recommend the proper solutions.

The most common symptoms of meniscus tear are:

  • Pain
  • Stiffness and swelling
  • Catching or locking of your knee
  • The sensation of your knee “giving way”
  • You are not able to move your knee through its full range of motion

When you tear a meniscus it’s fairly common for a piece of it to come a lose and wind up inside the joint. When that happens it can lodge behind the patella, or just start causing your knee to slip, pop, or lock up entirely.


Treatment will vary depending on the location and the size of the tear.

Unlike the articular cartilage that has no blood supply, about a 1/3 of the meniscus does get blood. That means that if the outer 1/3 is injured, it stands a good chance of healing itself over time. The inside 2/3 gets no blood so that a tear here usually means some sort of surgical intervention.

If your tear is pretty small and on the outer 1/3, there’s a good chance that rest, ice packs, a compression knee sleeve, and keeping your leg elevated for several hours a day will be your treatment plan.

Of course the best option here is going to be the non surgical method, but if that doesn’t provide knee pain relief, then your doctor will likely advise surgery.

Depending on the location of the injury and the severity there are two different possible surgical procedures:

1. Meniscectomy 

A partial meniscectomy is when part of the damaged meniscus is removed. The recovery time from a partial meniscectomy is usually between 4 and 6 weeks.

In the image you can see that the meniscus is torn on the inner edge which has no blood supply to heal itself, and can’t be sutured. In this case the tear will need to be trimmed away.

2. Suture Repairs

Sometimes the tears can be repaired with sutures — if it’s in the outer part with blood flow. Recovery from actual repairs can take as long as 3 months.

Suture repairs are made with arthroscopic surgery which a common surgery in the US. It involves inserting a very small camera into a knee then operating and viewing the procedure on a computer monitor as he/she works.

After surgery, you’ll have a rehabilitation period, that could be physical therapy at a rehab center or at home, depending on recommendations from the doctor. Either way all joint surgeries routinely involve exercises for improving range of motion and strength.


Meniscus tears usually happen with no warning. They tend to occur from making sudden turns with a lot of weight on knees.

The two best ways to avoid the pain of meniscus tears are:

  • Use leg exercises to ensure your legs stay strong to aid in stabilization of the knee joints
  • Use knee sleeves for the compression that adds extra support to the knee and surrounding joints.

Wearing one of these open patella knee sleeves can help you avoid the knee pain caused from meniscus tears.

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