Why Is My Knee Swollen? Common Causes, Treatments, and PT-Approved Exercises

Your knee is your largest joint. When you injure or irritate it — whether it’s from playing basketball or smacking it into the coffee table — it can be alarming to see how much it can swell up. But rest assured, swelling in the knee is very common. In many cases, knee swelling is due to an injury or simply doing more than your body is ready for at that time. As one Hinge Health member told us recently, their knee would swell up after a long day at work. “A routine of standing and walking for hours, along with going up and down stairs frequently, would have my left knee swollen and painful for hours,” they said.

But there are plenty of ways to manage knee swelling. One sure bet: doing exercise therapy to strengthen and support your knee and surrounding muscles. The Hinge Health member mentioned above, for example, shared that their knee is feeling better as they do more gentle knee stretches and strengthening exercises. “Now, my knee might ache a bit after getting home but it normally goes away quickly with no intervention. Overall the stretches seem to be working and my knees are feeling much better,” they said. 

Here, we’ll explain what causes knee swelling and pain and what you can do to relieve it and prevent having a swollen knee in the future.

What Is Knee Swelling?

Knee swelling, also known as knee effusion, simply means that there’s a buildup of fluid in your knee joint. Your knee joint is made up of three bones: the femur (thigh bone), the tibia (shin bone) and the patella (kneecap). Your knee normally contains 2-3 mL (about half a teaspoon) of synovial fluid, which helps to lubricate the joint. If it’s injured or inflamed, it can produce more. When this happens, your knee may feel stiff and tight. It may be hard to move around as well as you normally do. It may also hurt or feel warm to the touch.

Common Causes of a Swollen Knee

There are two main classifications of knee swelling, explains Justin Melson, PT, DPT, a physical therapist at Hinge Health: swelling from repeated stress and swelling from episodic stress. 

Repeated Stress 

Overuse. This type of knee swelling develops after you do more activity than your knee can presently handle. For example, increasing your running mileage rapidly (e.g., running 10 miles when you typically do three) or going on an hours-long hike on the weekend when you’ve been sedentary all week can put extra strain on your knee joint, leading to inflammation and swelling. 

Knee arthritis. When you have knee osteoarthritis, the cartilage on the ends of your knee bones changes over time. Everyone experiences changes in their cartilage over their lifetime. For some people, it wears down and reduces the amount of space between bones, which can lead to pain, stiffness, and swelling. Inflammatory forms of arthritis (like rheumatoid or psoriatic arthritis, where your immune system attacks your joints) are also known for causing knee swelling.

Bursitis. Bursae are small, jelly-like sacs that act as cushions to help reduce friction between your tendons and bones. If a bursa in your knee becomes irritated, often from muscle imbalances, says Dr. Melson, it causes them to overproduce fluid, which leads to knee swelling, (known as knee bursitis).

Episodic Stress 

Sprains. A knee sprain refers to an injury to one of the knee ligaments (strong bands of tissue that connect bones to each other). A sprain typically occurs when the ligament is stretched beyond its normal range, sometimes due to sudden twists, falls, or impact. The injury triggers an inflammatory response from the body as part of the healing process, which can lead to swelling along with other symptoms such as pain, bruising, instability, and reduced range of motion.

Tears. If you’ve ever skied or played basketball, you may have seen a teammate sidelined by an injury like an anterior cruciate ligament (ACL) tear. “These are more likely to occur if you play a sport where you have to cut or pivot a lot,” says Dr. Melson. You can also injure other knee ligaments, such as the posterior cruciate ligament (PCL) or the medial collateral ligament (MCL). “These sorts of injuries are pretty significant,” says Dr. Melson. If you have a recent history of trauma to your knee, notice your knee buckling, cannot bear weight through your knee, or suspect something more serious is going on with your knee, see a doctor. 

Note that in rare instances, knee swelling can be the result of an infection. Such causes of knee swelling can require urgent treatment (such as surgery). If you are concerned that the swelling might be associated with infection, you should see a medical provider right away.

Swollen Knee Treatment

Treatment for your swollen knee depends, in part, on what’s causing it. If the swelling is due to a serious injury or an infection, you should seek immediate medical attention. But for other causes of knee swelling, consider the following:

• Ice, ice baby. Apply a cold compress or ice packs wrapped in a thin towel to your knee a few times a day for 15 minutes at a time for as long as there is swelling. “Once the swelling goes down, heat may feel better, but ice is the best thing to help calm inflammation and get swelling down,” says Dr. Melson. 

• Elevate. Prop your knee and leg up above your heart as much as possible. This will help drain excess fluid from your knee joint, which can help healing and reduce swelling. 

• Consider a brace or knee sleeve. You can use braces and sleeves temporarily for additional compression and stability until the swelling resolves.

• Over-the-counter (OTC) medication. Non-steroidal anti-inflammatories (NSAIDs) such as ibuprofen (Advil, Motrin) and naproxen (Aleve) can help relieve knee swelling. Talk to your doctor before you use them, however, to make sure you can take them safely.

• Physical therapy. It’s a good idea to consider physical therapy to treat a swollen knee. A PT can address underlying causes of swelling, and work with you on a strengthening and stretching regimen to help prevent it from recurring. This is especially important if your swollen knee is from a tendon or ligament sprain or tear, notes Dr. Melson. “Many patients are afraid that if they use their knee, they’ll damage it even more,” he explains. “We work with them to get them moving safely in a way that works for them.” You can see a physical therapist in person or use a program like Hinge Health to access a PT via telehealth/video visit.

Afraid to Move or Exercise? Don’t Be

If you have a swollen knee, you may be worried about moving it, exercising, or even doing your usual daily activities. But moving is exactly what your physical therapist wants you to do. “The more you move it and use it, the more fluid you’ll push out and the more you’ll increase blood flow to the joint to encourage healing,” points out Dr. Melson.

These exercises recommended by Hinge Health physical therapists engage the muscles in your lower extremities, which helps pump fluid out of your knee and reduces swelling. 

Les physiothérapeutes de Hinge Health recommandent de renforcer les muscles des jambes et des hanches qui soutiennent tes genoux pour les garder en bonne santé et prévenir les blessures ou les irritations qui peuvent contribuer au gonflement. 

Les informations contenues dans ces vidéos sont destinées à une utilisation à des fins éducatives uniquement et ne constituent pas un conseil ou un traitement médical pour un problème de santé précis. Hinge Health n'est pas ton prestataire de soins de santé et n'est pas responsable des blessures ou de toute aggravation de blessures que ton application de ces exercices pourrait causer. Consulte ton prestataire de soins pour toute question concernant ton état de santé ou ton traitement.

Plus de conseils sur le Bien-être

En plus de faire régulièrement des exercices pour renforcer et étirer tes genoux et tes jambes, ces conseils peuvent t'aider à éviter les épisodes de genoux gonflés à l'avenir.

• Change d'activités. Si ton genou gonflé est lié au fait que tu fais plus d'activités que ton corps n'est prêt à en faire, pense à mélanger tes mouvements et tes activités. Essaie de faire des activités variées comme la marche, le vélo, la natation et tes sports et loisirs habituels. Cela fait travailler différents muscles et aide tes genoux à devenir plus sains et plus forts.

• Incorpore des "collations de mouvement" dans ta journée. Faire de courtes pauses tout au long de la journée pour changer de position permet de garder tes muscles forts et tes articulations souples tout en réduisant les gonflements. 

• Fais un échange de nourriture. Les aliments inflammatoires tels que les boissons et les en-cas riches en sucre, les aliments frits et les viandes transformées peuvent aggraver le gonflement. Envisage de troquer un aliment inflammatoire de ton régime alimentaire contre un aliment anti-inflammatoire (par exemple, les fruits, les légumes, les poissons gras) pour aider à modérer l'enflure. 

Conseil de physiothérapeute : Étire-toi 

Faire des étirements doux du genou régulièrement (tous les jours si possible) aide à garder tes muscles souples et prêts pour l'activité. Cela peut aider tes genoux à rester prêts à faire face à tes activités habituelles sans s'irriter. Les étirements constituent également un parfait "en-cas de mouvement" pour aider à interrompre une longue journée de travail ou toute situation où tu es resté sédentaire pendant un certain temps.

Comment Hinge Health peut t'aider

Si tu as des douleurs articulaires ou musculaires qui t'empêchent de bouger, tu peux obtenir le soulagement que tu cherchais grâce à la Thérapie par le mouvement Cheminement en ligne de Hinge Health. 

Le meilleur : Tu n'as pas besoin de quitter ton Accueil car notre Cheminement est numérique. Cela signifie que tu peux facilement obtenir les soins dont tu as besoin grâce à notre appli, quand et où cela te convient.  

Grâce à notre Cheminement, tu auras accès à des exercices thérapeutiques et à des étirements adaptés à ton état. De plus, tu auras une équipe personnelle de soins cliniques pour Guide, te soutenir et adapter notre cheminement à tes besoins. 

Vois si tu as droit à Hinge Health et confirme la couverture gratuite par ton employeur ou ton régime d'avantages sociaux ici.

Cet article et son contenu sont fournis à des fins éducatives et informatives uniquement et ne constituent pas des conseils médicaux ou des services professionnels spécifiques à toi ou concernant ton état de santé.

References

1. Gerena, L. A., Mabrouk, A., & DeCastro, A. (2023). Knee Effusion. PubMed; StatPearls Publishing. https://www.ncbi.nlm.nih.gov/books/NBK532279/#:~:text=effusions%20indicate%20pathology.-

2. Role of Body Weight in Osteoarthritis. (n.d.). John Hopkins Arthritis Center. Retrieved from https://www.hopkinsarthritis.org/patient-corner/disease-management/role-of-body-weight-in-osteoarthritis/

3. Bennell, K. L., Lawford, B. J., Keating, C., Brown, C., Kasza, J., Mackenzie, D., Metcalf, B., Kimp, A. J., Egerton, T., Spiers, L., Proietto, J., Sumithran, P., Harris, A., Quicke, J. G., & Hinman, R. S. (2022). Comparing Video-Based, Telehealth-Delivered Exercise and Weight Loss Programs With Online Education on Outcomes of Knee Osteoarthritis. Annals of Internal Medicine, 175(2), 198–209. doi:10.7326/m21-2388