Why Is My Knee Buckling?

Overview

Knee buckling—often described as the knee “giving way”—is a symptom of knee instability in which the knee suddenly feels weak and may fail to support the body during weight bearing. It can occur once or repeatedly and, when frequent, is associated with a higher risk of falls and injuries.

Understanding the underlying cause is important because evaluation and treatment depend on what is driving the instability.

What Is Knee Buckling?

Knee buckling refers to episodes of instability during weight bearing, commonly described as a sudden loss of postural support across the knee. Medical literature and clinical sources describe this sensation as the knee “giving way” and classify it as a symptom rather than a standalone diagnosis.

Causes of Knee Buckling

Knee Injuries

• Anterior cruciate ligament (ACL) injuries:
  ACL tears are a well-established cause of knee instability, particularly during turning or pivoting movements. Symptoms may include popping, swelling, pain, and difficulty bearing weight.
• Meniscus tears:
  The meniscus cushions the knee joint. Tears can cause mechanical symptoms such as locking and may contribute to instability or giving way.

Plica Syndrome

Plica syndrome is another possible culprit behind knee buckling. The plica is a small fold of synovial tissue inside the knee joint—essentially, a natural part of your knee’s inner lining. When this tissue becomes irritated or inflamed, often as a result of overuse or trauma, it can contribute to instability and the sensation of the knee unexpectedly giving way.

In addition to episodes of buckling, plica syndrome may present with:

• Clicking or snapping sensations within the knee
• Discomfort along the inner side of the knee
• Tenderness or pain around the kneecap

Plica syndrome frequently arises after repetitive knee movements or an abrupt injury. Management is usually conservative: physical therapy focused on strengthening the muscles around the knee and improving stability is often effective. Occasionally, corticosteroid injections are used to calm inflammation. In persistent cases where symptoms don’t resolve, minor surgical removal or adjustment of the irritated plica may be considered.

Plica Syndrome

Plica syndrome occurs when the medial plica—a fold in the lining of the knee joint—becomes irritated or inflamed. This condition can contribute to sensations of knee buckling, as well as other distinctive symptoms such as:

• Clicking or snapping sounds with knee motion
• Discomfort or pain along the inner side of the knee
• Tenderness around the kneecap, especially after activity

Plica issues are often triggered by repetitive knee use or following an injury that leads to inflammation.

Treatment options focus on reducing irritation and restoring knee stability. Conservative measures typically include physical therapy to strengthen surrounding muscles, activity modification, and anti-inflammatory strategies like corticosteroid injections. In rare cases, if symptoms persist despite non-surgical treatment, minimally invasive surgery may be considered to remove or reshape the irritated plica.

Arthritis

• Osteoarthritis and rheumatoid arthritis:
  Arthritis is associated with knee buckling. Cartilage loss and joint changes can lead to pain, stiffness, and instability, making the knee more likely to give way.

Muscle Weakness

• Quadriceps weakness:
  Weakness in the muscles above the knee is associated with an increased risk of knee buckling. Strengthening and rehabilitation are commonly used non-surgical approaches in related instability.

Nerve-Related Conditions

• Femoral neuropathy:
  Dysfunction of the femoral nerve can cause weakness, numbness, or tingling in the leg, increasing susceptibility to knee buckling. This nerve is one of the two major nerves in the lower leg, and when it’s affected, you may also experience burning sensations, pain, or a sense of instability around the knee. Other signs may include numbness or tingling in parts of your thigh or lower leg.
• Several factors can contribute to femoral neuropathy, such as:
• Diabetes
• Certain medications
• Arthritis
• Heavy alcohol consumption
• Neurological disorders (like fibromyalgia)
• Direct injuries to the nerve
• If you notice persistent weakness or sensory changes in your leg, consider consulting a healthcare provider to identify the underlying cause and discuss appropriate treatment options.
• Multiple sclerosis (MS):
  Some people with MS report knee buckling as a symptom related to leg weakness or sensory changes.

Multiple Sclerosis and Its Related Symptoms

Multiple sclerosis (MS) is a neurological condition in which the immune system damages the protective covering of nerves, affecting nerve signals throughout the body—including those that control the muscles around the knee. When MS impacts the nerves serving the leg, the result can be muscle weakness, numbness, or altered sensation, all of which contribute to knee buckling or instability.

Apart from weakness and sensory changes in the legs, individuals with MS often experience:

• Vision disturbances or loss
• Persistent fatigue
• Episodes of dizziness or lightheadedness
• Involuntary muscle tremors

These symptoms may vary widely in severity and presentation from person to person. While there is no cure for MS, treatment options such as corticosteroids may help reduce nerve inflammation, and muscle relaxants may alleviate issues like stiffness or muscle spasms that could worsen instability.

Symptoms That May Occur With Knee Buckling

Knee buckling may occur alone or with other symptoms, including:

• Knee pain or swelling
• Locking, popping, or grinding sensations
• Difficulty bearing weight
• A feeling of looseness or instability

These symptoms are commonly reported in knee injuries and arthritis and help clinicians assess possible causes.

When Knee Buckling Happens Most Often

Clinical sources indicate that knee buckling may occur:

• During walking or changing direction
• When standing up from a seated position
• During squatting, running, or sports activities
• While going up or down stairs

How Knee Buckling Is Evaluated

People with frequent knee buckling are advised to seek medical evaluation.

There is no high-quality evidence defining a single, standardized diagnostic sequence (such as a required order of physical examination, imaging, or neurologic testing) specific to knee buckling alone. Evaluation is individualized based on symptoms and suspected causes.

What to Do While Waiting for Medical Evaluation

If you’re experiencing frequent knee buckling and have a medical appointment scheduled, taking certain precautions can help protect your knee and minimize the risk of falls or further injury before you see a healthcare provider.

• Limit aggravating activities:
  Try to avoid movements or activities that trigger buckling, such as sudden turns or prolonged standing.
• Use support as needed:
  Consider using a cane, walking stick, or knee brace to provide stability and reduce your risk of falling during daily activities.
• Apply ice or heat:
  Applying an ice pack can help with swelling or discomfort, while gentle heat may ease muscle stiffness—choose whichever offers you more relief.
• Rest and elevation:
  Give your knee a chance to recover by minimizing strain. Elevating your leg when sitting may also help reduce swelling after episodes of giving way.
• Gentle strengthening exercises:
  If you are able, performing basic, pain-free leg exercises—such as straight leg raises or gentle quad sets—may help support the knee. Avoid any exercises that worsen symptoms.

If your symptoms suddenly worsen—such as marked swelling, severe pain, or inability to bear weight—seek prompt medical attention.

Treatment Options

Treatment depends on the underlying cause rather than the symptom alone.

• Physical therapy:
  Used to improve strength and stability in many non-surgical cases.
• Bracing or assistive devices:
  Knee braces or supports may reduce fall risk and improve confidence during movement.
• Medications and injections:
  Pain medications or corticosteroid injections are used in some conditions, such as arthritis or nerve inflammation.
• Surgery:
  Reserved for specific structural problems, such as significant ligament tears or advanced arthritis. Not all cases require surgery, and many improve with conservative care.

Managing Knee Buckling in Multiple Sclerosis

When knee buckling is related to multiple sclerosis (MS), treatment is aimed at addressing the underlying muscle or nerve symptoms. Corticosteroid injections may be used to reduce nerve inflammation, especially during flare-ups. For those experiencing persistent stiffness or muscle spasms, muscle relaxant medications are sometimes prescribed to improve mobility and help manage sudden episodes of weakness. As with other causes of knee buckling, management plans are individualized and often include physical therapy or targeted rehabilitation to enhance strength and stability.

Treatment of Femoral Neuropathy

Management of femoral neuropathy is tailored to the underlying cause and may involve several approaches:

• Medications: Pain relievers, anti-inflammatory drugs, or medications targeting nerve pain are often prescribed to help manage symptoms.
• Physical therapy: Rehabilitation can help restore strength and mobility, reduce discomfort, and support functional improvement.
• Lifestyle modifications: Addressing contributing factors such as blood sugar control in diabetes or avoiding activities that aggravate symptoms can be beneficial.
• Surgical intervention: In cases where nerve compression or injury is identified, surgery may be considered to relieve pressure or repair damaged structures.

While a complete cure is not always possible, especially if nerve damage is advanced, treatment is focused on improving symptoms and preventing further progression.

When to See a Doctor

Medical evaluation is recommended if knee buckling:

• Happens repeatedly
• Occurs after a knee injury
• Is accompanied by pain, swelling, or difficulty bearing weight
• Interferes with daily activities

Frequent knee buckling can range from a mild annoyance to a serious health hazard, especially if it leads to falls. If you notice your knee giving out more than once, or if the episodes are linked with pain or swelling, don’t wait to get it checked out. This is particularly important after an injury or if the buckling makes everyday tasks—like walking up or down stairs—difficult or unsafe.

While you’re waiting to see your healthcare professional, rest your knee as much as possible. Applying a hot or cold compress may help with discomfort or swelling. For added support and to lower your risk of falling, consider wearing a knee brace or using a cane when you walk.

Key Takeaways

• Knee buckling is a symptom, not a diagnosis.
• It is associated with injuries, arthritis, muscle weakness, and some nerve-related conditions.
• Frequent knee buckling is linked to a higher risk of falls and injuries.
• Treatment focuses on the underlying cause, not the sensation alone.
• Medical evaluation is recommended when buckling is recurrent, post-injury, or interferes with daily activities.

Remember: working with your healthcare professional is the best way to determine what’s causing your knees to give out—and to find an effective treatment plan.

Frequently Asked Questions

APA Reference List

American Academy of Orthopaedic Surgeons. (n.d.). Anterior cruciate ligament (ACL) injuries. OrthoInfo. https://orthoinfo.aaos.org/en/diseases–conditions/anterior-cruciate-ligament-acl-injuries/

American Academy of Orthopaedic Surgeons. (n.d.). Meniscus tears. OrthoInfo. https://orthoinfo.aaos.org/en/diseases–conditions/meniscus-tears/

Cleveland Clinic. (2025, January 30). Knee osteoarthritis: Symptoms, stages, causes & treatment. https://my.clevelandclinic.org/health/diseases/21750-osteoarthritis-knee

Healthline Media. (2024, October 22). Knee buckling: 5 causes and how to treat them. https://www.healthline.com/health/knee-buckling

Houston Sports Orthopedics. (n.d.). Knee popping, locking, buckling, and giving out. https://houstonsportsortho.com/locking-popping-buckling-knee-specialist-houston-tx/

Mayo Clinic. (2022, December 1). ACL injury: Symptoms and causes. https://www.mayoclinic.org/diseases-conditions/acl-injury/symptoms-causes/syc-20350738

National Institute of Arthritis and Musculoskeletal and Skin Diseases. (2023, September 1). Osteoarthritis. https://www.niams.nih.gov/health-topics/osteoarthritis

National Library of Medicine. (2024, June 17). Anterior cruciate ligament (ACL) injury. MedlinePlus Medical Encyclopedia. https://medlineplus.gov/ency/article/001074.htm

National Library of Medicine. (2025, June 4). Meniscus tears—Aftercare. MedlinePlus Medical Encyclopedia. https://medlineplus.gov/ency/patientinstructions/000684.htm

National Library of Medicine. (2025, June 23). Knee injuries and disorders. MedlinePlus. https://medlineplus.gov/kneeinjuriesanddisorders.html

Nevitt, M. C., Tolstykh, I., Shakoor, N., Nguyen, U.-S. D. T., Segal, N. A., Lewis, C., Felson, D. T., & the Multicenter Osteoarthritis Study Investigators. (2016). Symptoms of knee instability are risk factors for recurrent falls. Arthritis Care & Research, 68(8), 1089–1097. https://doi.org/10.1002/acr.22811

Patel, R. M. (2023, March 21). Why is my knee buckling? https://www.drronakpatel.com/blog-munster-hinsdale-westmont-elmhurst-il/why-is-my-knee-buckling-17317/