Weak Knees - Causes, Diagnosis, Treatment, and Prevention

Introduction:

The knee is a complex joint that allows a wide range of motion. There are a lot of knee muscles to control the movements while walking, running, squatting, and going up or down the stairs. As we use our knees to work all day long for the daily chores, there is no surprise in experiencing knee weakness or instability. Weak knees are otherwise known as knee buckling. However, if the knees become weak, it can raise the risk of falling or seriously injuring yourself, so it is very important to address the underlying cause and treat it.

How Does the Knee Work?

The knee is typically a hinge joint that connects the thigh bone to the lower leg bones. There are certain connective tissues called ligaments that connect the bones and stabilize the joints. Some of the ligaments include:

• Collateral ligaments.

• An anterior cruciate ligament (ACL).

• A posterior cruciate ligament (PCL).

Collateral Ligaments:

The collateral ligaments are present on either side of the knee. There are two types of collateral ligaments:

• Medial collateral ligament - which is located on the inner side of the knee.

• Lateral collateral ligament - located on the outer side of the knee.

Anterior Cruciate Ligament (ACL):

The anterior cruciate ligament runs through the middle of the knee. It connects the shinbone and the thigh bone. This ligament limits the rotation and the forward motion of the shinbone.

Posterior Cruciate Ligament:

The posterior cruciate ligaments connect the top and rear of the shinbone to the thigh bone. This ligament limits the backward motion of the shinbone.

All four ligaments carry out specific functions.

What Are the Major Causes of Weak Knees?

Here are some of the major causes of weak knees:

• Injuries or tears.

• Nerve damage.

• Plica syndrome.

• Other medical conditions.

1. Injuries or Tears:

Often weak knees or knee instability is caused due to injuries or ligament tears resulting from high-impact activities like running accidents. Some of the common injuries include:

• Ligament tears.

• Meniscus tears.

• Patellar dislocation.

a. Ligament Tears:

Ligament tears could be a major cause of weak knees or knee instability. There can be partial or complete ligament tears. These ligaments often get injured during any athletic activity. Even simple daily activities can result in overuse or sprain. The extent to which the ligaments get damaged determines the need for medical attention. The types of ligament tears include:

• Anterior Cruciate Ligament (ACL) Tears: ACL tear occurs with sudden movements, such as changing direction during sports or during a car accident.

• Posterior Cruciate Ligament (PCL) Tears: PCL tears generally occur when an individual suddenly lands on the front of the knee. This type of tear occurs along with other injuries rather than on its own.

• Medial Collateral Ligament (MCL) Tears: MCL tears when the outer side of the knee gets hit. If there is knee instability, then it indicates an MCL tear.

• Lateral Collateral Ligament (LCL) Tears: When the LCL tears, there will be pain in the outer part of the knee.

b. Meniscus Tears:

Menisci are cartilage pads. They are basically the shock absorbers of the knee and help stabilize it. There are two menisci per knee. Meniscus tears occur during activities like twisting, turning, or pivoting. This meniscus tear is common in people around the age of 30 and above because the meniscus weakens during that time.

The symptoms of a meniscus tear include:

• Swelling.

• Pain.

• Popping or locking feeling.

• Stiffness.

• Difficulty with movement.

c. Patellar Dislocation:

A direct blow to the kneecap from an accident or sports injury can dislocate it from the groove resulting in patellar instability. There are two types of patellar instability:

• Patellar Dislocation - the kneecap is totally moved outside of its groove.

• Subluxation - in the case of subluxation, the kneecap is partially out of its groove.

2. Nerve Damage:

The femoral nerve is one of the two major nerves of the lower leg. This femoral nerve is located in the pelvis and goes down the thigh and the shinbone. When the femoral nerve gets damaged, it can make it feel like the knee is giving out. This also causes tingling or burning pain around the knee. The femoral nerve gets damaged when the individual gets injured or when the nerve experiences a lot of pressure.

3. Plica Syndrome:

Plica syndrome refers to a condition where the inner lining of the knee joint is inflamed. It usually occurs during movements like bending. The symptoms of plica syndrome include:

• Knee pain.

• Clicking or popping feeling when moving.

• Difficulty with movement.

4. Other Medical Conditions:

The medical conditions that can cause weak knees include:

a. Arthritis: Arthritis refers to an inflammatory condition of the joints. There are multiple types of arthritis. Among all the types, weak knees or knee instability is a common symptom of osteoarthritis and rheumatoid arthritis. The symptoms of arthritis include:

- Swelling.

- Stiffness.

- Pain.

- Difficulty with movement.

b. Multiple Sclerosis: Multiple sclerosis is a condition that causes the immune system to affect the protective covering of the nerves. The symptoms of multiple sclerosis include,

• Tremors.

• Fatigue.

Who Is More Likely to Develop Weak Knees or Knee Instability?

There are certain conditions that can increase the risk of developing weak knees. Here are a few:

• People who are engaged in sports, particularly football or skiing.

• People who ignore knee pain.

• People with a history of torn ligament surgery.

• Arthritis.

• People with a history of knee replacement.

How Are Weak Knees or Knee Instability Diagnosed?

The diagnosis of weak knees or knee instability is made with a detailed medical history, physical examination, and imaging studies.

Physical Examination:

A physical examination is performed to see for the following signs:

• Bruise.

• Tenderness.

• Any sounds while pushing or moving the knee cap.

• Any deformities in the knee.

There are a few tests done to examine ligament and meniscus tears:

• McMurray’s test- the patient is asked to rotate their knees to identify tears.

• Ege’s test- The doctor asks the individual to squat to look for clicking sounds.

Imaging Tests:

Imaging studies such as X-rays are performed to look for dislocation and ligament injuries.

What Are the Ways to Treat Weak Knees or Knee Instability?

The treatment for weak knees or knee instability depends on the underlying cause. The general treatments include:

• RICE Method.

R- Rest.

I- Ice.

C- Compression.

E- Elevation.

• Nonsteroidal anti-inflammatory drugs (NSAIDs) are prescribed for pain.

• Knee rehabilitation exercises.

In case of torn ligaments, knee surgery may be required.

Can the Weak Knees Be Made Stronger?

There are certain knee exercises that are recommended by doctors for weak knees or knee instability. These knee strengthening exercises do not directly affect the knee joint but rather strengthen the muscles around the knee by increasing the blood flow to the muscles and making them more flexible. Here are a few knee strengthening exercises:

• Leg lifts.

• Standing hamstring curls.

• Hamstring curls on a weight bench.

• Step exercises.

• Single-leg dip.

• Wall squats.

Can We Prevent Our Knees From Getting Weaker?

• Firstly, do not neglect knee pain. If you have any knee-related symptoms, immediately seek medical attention.

• Do some knee strengthening exercises.

• Wear a knee brace.

• Try avoiding overuse injuries.

• And wear a seat belt while driving to minimize the risk of a dashboard-related knee injury.

Conclusion:

If you are having any knee pain or knee-related symptoms, do not neglect to seek medical care. Exercises are a noninvasive and healthiest way to help prevent injuries and to keep the knees strong. However, it is wise to consult the doctor before planning any exercise program or treating the condition on your own.