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.
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. - Multiple sclerosis (MS):
Some people with MS report knee buckling as a symptom related to leg weakness or sensory changes.
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.
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.
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
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.
Frequently Asked Questions
What causes a knee to buckle while walking?
Verified sources associate knee buckling with injuries (such as ACL or meniscus tears), arthritis, muscle weakness, and some nerve-related conditions.
Is knee buckling serious?
Knee buckling ranges from a mild nuisance to a serious health concern. Frequent episodes are associated with an increased risk of falls and injuries.
Can arthritis cause knee buckling?
Yes. Osteoarthritis and rheumatoid arthritis are associated with knee buckling, pain, stiffness, and instability.
Can physical therapy help knee buckling?
Physical therapy is commonly used for conditions involving muscle weakness, arthritis, and some injuries. Effectiveness depends on the underlying cause.
Can nerve problems cause knee buckling?
Yes. Femoral neuropathy and multiple sclerosis are associated with knee buckling due to weakness or sensory changes.
Does knee buckling always mean ligament damage?
There is no high-quality evidence supporting this. Knee buckling can occur with ligament injuries, arthritis, muscle weakness, or nerve-related conditions.
How long does knee buckling last?
There is no high-quality evidence supporting a specific duration. Duration depends on the underlying cause and treatment.
Can knee buckling be prevented?
There is no high-quality evidence supporting specific prevention strategies exclusively for knee buckling. Management focuses on treating underlying conditions.
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/