Knee Instability: The Problem and How to Prevent It

As an Amazon Associate I earn from qualifying purchases.


If you have knee problems, then you understand that shaky, unstable feeling. Knee instability may feel like your knees could give way, or they might actually pop out of place from time to time. Either way, the pain involved is not too much fun.

What Is Knee Instability?

Knee instability is also known as knee buckling or weak knees. Sometimes it is painful. However, this is not always the case. If it has happened to you once or twice, then you may have only stumbled.

If it continues to occur, then you might have another condition. The result of your knees buckling may be a serious fall. So, you want to get to the bottom of what the problem is before this happens.

What Are the Causes of Knee Instability?

Healthline lists the following causes of knee instability:

1. Injury

Many times, knee instability is the result of an injury. This could come about from high impact sports activities or accidents.

Typical knee injuries include:

  • ACL tears
  • Meniscus tears
  • Loose bodies

Besides instability, knee injuries can result in pain and be swelling in the injured knee.

If you have instability from an injury, treating the injury will resolve the issue. Possible treatments include physical therapy and surgery. During the process of recovery, you should not put pressure on the knee more than you have to.

2. Nerve Damage

The femoral nerve is an important nerve in the lower part of your leg. Femoral neuropathy is a problem in the functioning of this nerve. When there are issues with this nerve, it can result in knee instability.

The other symptoms of this neuropathy include:

  • Pain
  • Tingling
  • Burning
  • Numbness

The causes of femoral neuropathy include:

  • Diabetes
  • Some drugs
  • Arthritis
  • Too much alcohol
  • Neurological disorders
  • Injuries

Healthline gives a list of treatment options for this condition:

When you have femoral neuropathy, you must deal with the underlying cause. If the problem is compression on the nerve, then you will need to relieve the compression. If the problem is diabetes, then bringing blood sugar within normal range may resolve the problem.


You have a few options here: You may go for corticosteroid injections in the leg to inhibit inflammation and swelling. Pain medications can aid in relieving pain and discomfort. Your doctor may also prescribe a medication such as gabapentin or pregabalin.


Physical therapy works by building the strength in your leg muscles. Your therapist can instruct you in exercises that will strengthen your muscles. The therapy can aid in reducing pain and increasing mobility.

You may need an orthopedic device. This may be a brace. A knee brace can aid in stopping knee buckling.

You may also need occupational therapy. This therapy will help you to do regular tasks like bathing. Your doctor might also advise you to pursue vocational counseling if you need to find some other kind of work.


Your doctor may recommend surgery if you have a growth blocking the nerve. Taking away the growth will relieve the pressure on the nerve.

3. Plica Syndrome

Plica syndrome is the result of inflammation of the medial plica. This is a fold in the center of the membrane that lies over the knee joint.

This condition may cause:

  • Clicking sounds in the knee
  • Pain on the inside of the knee
  • Pain and tenderness in the kneecap

Most instances of plica syndrome are the result of injury or overuse of the knee.


Plica syndrome usually gets better without surgery, according to WebMD. You will need to rest the knee and apply ice to it.

Your doctor might recommend pain medications. These may include ibuprofen or naproxen. You should also stretch your leg muscles, particularly the quadriceps and hamstrings.

You can do some exercises to prevent the problem. These include straight leg presses, mini-squats, walking, or swimming. You may want to see a physical therapist to help you develop a specific regimen.

If the pain doesn’t go away, then you might need surgery. This may be arthroscopic surgery. In this procedure, the surgeon makes small incisions and inserts a camera and thin tool to remove the damaged tissue. You will probably need physical therapy after the operation.

4. Arthritis

Arthritis is inflammation of the joints. It can happen in the knees. There are many kinds of arthritis, but knee buckling many times results from osteoarthritis and rheumatoid arthritis. Rheumatoid arthritis will usually occur in both knees, and osteoarthritis may only affect one knee.

Both kinds of arthritis may result in:

  • Pain
  • Stiffness
  • A locking or sticking sensation
  • A grinding or clicking noise

Treatment for Arthritis


These are pain relievers, such as acetaminophen or tramadol. They relieve pain but don’t relieve inflammation or swelling.

Topical Analgesics

These are creams that can be applied to the skin over the affected area. The active ingredients in these creams are typically counterirritants.


These are non-steroidal anti-inflammatory drugs. They include aspirin, ibuprofen, and naproxen. These drugs help with inflammation and swelling.

Physical Therapy

Physical therapy uses exercises that aid in maintaining the ability to perform everyday tasks.


Steroid Injections

These are administered if the pain is moderate to severe. They are used especially if the pain interferes with the patient’s ability to do exercises. If they are combined with physical therapy, then they may make the therapy more feasible.

Hyaluronic Acid Injections

This is another type of injection that is designed to help lubricate the joint and reduce its pain and inflammation.


For most patients, surgery is not necessary. However, if the pain is regular and severe, then surgery may be a viable option.

5. Multiple Sclerosis

Some people who have multiple sclerosis have knee instability as a symptom. MS is a condition that causes the immune system to destroy the protective covering of the nerves.

There is no cure for MS, but corticosteroid injections can aid in reducing nerve inflammation in the legs. Muscle relaxants can also help with stiffness or spasms in the legs.

6. Patellofemoral Pain Syndrome

The kneecap or patella is located directly in front of the thigh bone or femur. Normally, it should glide freely up and down. In patellofemoral pain syndrome, the patella rubs against the femur. This causes damage and pain.

If you have this problem, then you should see your primary care physician. He or she will coordinate care with a physical therapist to restore normal function of the knee and to reduce the pain. Mayo Clinic has more information about this condition.

7. Meniscal Injury

A common injury is the torn meniscus. An activity that results in twisting of the knee can lead to a torn meniscus.


Rest, ice, and medication are many times enough to take care of a torn meniscus. Sometimes, however, surgery is needed to repair it. Your doctor will need to make this determination.

8. Dislocated Kneecap

The kneecap connects the muscles in the front of the thigh to the shinbone or tibia. When the kneecap moves out of the groove, it can cause pain.

For this issue, you should see your primary care physician. He or she will return it to its proper place. This is called reduction.

9. ACL Injury

The ACL is a tendon that connects the femur to the tibia. This tendon can tear in an accident.

For this problem, you should seek immediate care at an ER. This tear requires surgery.

10. Baker’s Cyst

This is also known as a popliteal cyst. It is a fluid-filled mass that results in a bulge and a feeling of tightness behind the knee. The pain can worsen when the knee is fully flexed.

Treating the underlying problem will usually provide relief. Surgery is sometimes needed, but not usually.

11. Osteochondritis Dissecans

This condition is one where a piece of cartilage with a thin layer of bone detach from the larger bone.

You should see your primary care physician. Rest and physical therapy is the first line of treatment. Surgery is necessary if other treatments fail.

12. Pigmented Villonodular Synovitis

The synovium is a thin layer of tissue that surrounds joints. In this condition, the synovium thickens and overgrows.

You should see your primary care physician who will coordinate care with an orthopedic surgeon. The treatment for this condition is surgery and radiation therapy.

When Should You See a Doctor?

In general, with knee pain, you should see a doctor if you:

  • Can’t bear weight on your knee
  • Have marked knee swelling
  • Can’t fully extend or flex your knee
  • Notice a deformity in your leg or knee
  • Have a fever
  • Feel as if your knee is unstable or your knee gives out.

What Are Other Types of Things that Can Cause Knee Pain?


The bones of the knee can be broken during car accidents or falls. People who have osteoporosis can sometimes get a knee fracture just by taking a misstep.

Knee Bursitis

Certain knee injuries result in inflammation in the bursae. These are the small sacs of fluid that cushion the outside of your knee joint. They allow tendons and ligaments to glide smoothly over the joint.

Patellar Tendinitis

Tendinitis is a condition of the tendons. These are the tissues that bind muscles to bones.

Iliotibial Band Syndrome

This condition happens when the band of tissue that runs from the outside of the hip to the outside of the knee gets so tight that it rubs against the outer part of the femur. People who run distances are particularly prone to this condition.

Hip or Foot Pain

When you have hip or foot pain, you might alter the way that you walk. This altered way of walking can place stress on the knee joint.


This condition occurs when uric acid crystals build up in the joint. Gout usually affects the big toe, but it can also affect the knee.


Similar to gout, pseudogout occurs when calcium crystals develop in the joint fluid.

Septic Arthritis

The knee joint may get infected. It often occurs with a fever.

Risk Factors

There are certain factors that can increase the risk of getting knee problems. These include:

Excess Weight

Extra weight puts stress on all of the joints in the body. It also puts you at increased risk of osteoarthritis by speeding up the breakdown of joint cartilage.

Lack of Muscle Flexibility or Strength

A lack of strength and flexibility are among the main causes of knee problems. Tight or weak muscles provide less support for the knees.


Certain sports put more stress on the knees than others do. Skiing, basketball, and running increase your risk of knee injury.

Previous Injury

If you injure your knee, then it is likely that you will injure it again.

How Do You Prevent Knee Pain?

Maintain a Healthy Weight

This is one of the best things that you can do for your knees. Even a little extra weight can put stress on your knees and possibly cause arthritis.

Stay in Shape for Your Sport

You need to train to properly develop your muscles to practice your sport. You should work with a coach or trainer to ensure that your technique and movement are the best that they can be.

Practice Your Form

Your form is very important to prevent injury. You should consult a professional to help with this.

Get Strong and Flexible

Mayo Clinic recommends that you should build up your muscles that support the knee. These include your quadriceps and hamstrings.

Be Careful about the Way that You Exercise

If you have knee problems, then you need to change the way that you exercise. You can switch to swimming or other low impact exercises.


Knee instability is a kind of knee problem that can make everyday activity a real problem. Fortunately, there are things that you can do to prevent the issue. For exercises that can help stabilize the knee, look at the following YouTube video.