Orthopedics Hip & Knee Causes of Pain What Causes a Stiff Knee After Sitting? By Kimberly Charleson Kimberly is a health and wellness writer with 8 years of experience in healthcare and a special passion for mental health awareness. Learn about our editorial process Kimberly Charleson Published on January 14, 2021 Print Table of Contents View All Causes of Knee Stiffness Diagnosis Treatment You may experience knee stiffness with pain, especially after sitting or being inactive. Injury and conditions that affect the knee joint like osteoarthritis and rheumatoid arthritis can also be reasons why your knees feel stiff. Knee stiffness is characterized by difficulty moving the knee and a feeling of tightness in and around the joint. Other symptoms like muscle weakness and swelling may also occur alongside a stiff knee. What Can Cause Your Knee to Give Out? PeopleImages / Getty Images Causes of Knee Stiffness Most people experience knee stiffness after sitting for a long period of time. Stiff knees are a result of inflammation and fluid build-up in the knee joint, which causes tightness and inability to move it freely. A number of conditions can lead to inflammation and subsequently knee stiffness. Bursitis Bursitis occurs when the bursa becomes inflamed. Bursae are fluid-filled sacs that help reduce friction in the joints as they move, and there are several bursae in the knee joints. Overuse is the most common cause of bursitis. Sitting for long periods of time can often cause the knee to feel stiff for people with this condition. Arthritis Osteoarthritis, also known as wear-and-tear arthritis, can also cause stiff knees. It is the most common form of arthritis, affecting 10% of men and 13 % of women in the 60-and-over demographic. However, if the knee joint is overused or injured frequently, osteoarthritis can affect young people as well. Arthritis of the Knee Joint: Symptoms, Causes, Diagnosis and Treatment Rheumatoid arthritis (RA), an autoimmune disease, is also commonly associated with joint stiffness. If you experience knee stiffness along with additional symptoms like fever and fatigue, your may have RA. A hallmark feature of RA is morning stiffness. Pain and Swelling Could Mean Rheumatoid Arthritis Injury Injury to the knee joint can happen to athletes playing sports or to anyone during everyday activities. Ligament injuries can happen from hyperextension of the knee or trauma. Along with stiffness, you may experience swelling and pain from the injury. Another common injury is a tear of the meniscus, which is the cartilage of the knee. This often happens when twisting the knee, and is common in sports that require a lot of squatting, twisting, and changing positions. You will feel a pop when your meniscus is torn. Similarly, this injury will cause knee pain, swelling, and stiffness. Understanding Different Knee Injury Symptoms Patellofemoral Pain Syndrome Patellofemoral pain syndrome (PFPS) describes pain in the front of the knee and around the kneecap (patella). PFPS is often the result of overuse or malalignment of the kneecap. It's also referred to as runner's knee or jumper's knee because it's most common in people who play sports. It affects women at a higher rate. PMPS causes stiffness as well as pain in and under the kneecap. Sitting for long periods of time will result in increased pain and stiffness. Physical Therapy Exercises to Treat Runner's Knee Surgery Surgery often results in some level of knee stiffness post-op. Arthrofibrosis, also called stiff knee syndrome, can happen after surgery on the knee. The body's natural response to trauma, such as from injury or surgery, is to make scar tissues. Arthrofibrosis is when there is too much scar tissue around the knee joint, causing the knee to tighten and resulting in knee stiffness. Arthrofibrosis can occur after common knee surgeries, including: Total knee replacementACL reconstructionKnee arthroscopyKnee ligament replaceTendon repairPlica excision What Types of Surgery Are Used to Treat Knee Injuries? Low Flexibility or Strength Maintaining flexibility (the ability of joints to move through an unrestricted range of motion) throughout the body is beneficial in the long run for minimizing knee stiffness. Having the support of strong muscles around the knee joint also makes it less prone to injury. To avoid stiffness from tight muscles, add stretching to your fitness routine and prioritize strength-building exercises for the legs to support the knees. Knee Stretches You Should Be Doing for Maximum Health Benefits When to See a Doctor While knee stiffness is common, it can also be the sign of a serious condition. Call your doctor immediately if you experience the following symptoms:Increased swellingParalysisLoss of sensationComplete inability to move the knee jointAbsent pulses in the feetColdness of the feetHigh feverSevere bleedingUncontrollable pain Diagnosis Your doctor will take a full history, take note of all symptoms, and ask about any recent injuries. Tests to diagnose the underlying cause of stiff knees include blood tests to look for signs of arthritis, x-ray to investigate a possible fracture, or a CT scan to look for tears. Rheumatoid Arthritis: Blood Tests for Diagnosis Treatment Treatment will depend on the cause of your knee stiffness. Conditions like osteoarthritis and rheumatoid arthritis will require long-term treatment and follow-up with your doctor. Whether your knee stiffness is the result of a chronic disease or an injury, however, there are ways you can get relief for your stiff knees. Self-Care Strategies Self-care can be done at home to prevent or alleviate knee stiffness. These strategies include: RICE (rest, ice, compression, and elevation)Warming up before stretchingStretching before working outTaking non-steroidal anti-inflammatory drugs like aspirin or ibuprofenWearing a knee braceStrengthening the surrounding musclesIncorporating walks and a standing desk into your work routineChoose low-impact exercise like yoga Above all, listen to your body. Don't overdo it, and if the stiffness came from an injury, seek medical help. The Benefits of Yoga for Bad Knees Medical Treatment If your knee pain is serious and requires medical attention, your doctor will move forward with a treatment plan depending on your diagnosis. Treatment options include: Prescription pain medicationCortisone injectionsLubricant injectionsKnee surgeryDisease-modifying antirheumatic drugs for conditions like rheumatoid arthritisPhysical therapyReferral to an orthopedic surgeon Keep in mind that self-care strategies can be done alongside medical treatment for best results. What to Expect From Physical Therapy for Knee Pain A Word From Verywell Stiffness in the knee joint can be alarming and interfere with daily life. Whether this symptom comes from an injury or underlying condition, doctors see it often and can help you create a treatment plan that works for you and alleviates your symptoms. The earlier you identify what is causing your knee stiffness, the better your outlook will be. Practice self-care and choose exercises that keep your knees healthy and range of motion intact. Was this page helpful? Thanks for your feedback! Dealing with joint pain can cause major disruptions to your day. Sign up and learn how to better take care of your body. Click below and just hit send! Sign Up You're in! Thank you, {{form.email}}, for signing up. There was an error. Please try again. What are your concerns? Other Inaccurate Hard to Understand Submit Article Sources Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy. Zhang Y, Jordan JM. Epidemiology of osteoarthritis. Clin Geriatr Med. 2010;26(3):355-369. doi:10.1016/j.cger.2010.03.001 American Academy of Orthopedic Surgeons. Patellofemoral Pain Syndrome. Updated October 2020. Healthgrades. Stiff Knee. Updated November 30, 2020.