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Lump On Knee

A knee lump is a deformity caused by a chronic inflammatory condition like arthritis, or it can be a deformity caused by any type of joint damage. Knee lumps can also be caused by a variety of different illnesses, such as infections or bone or soft tissue cancers. Lumps can be solitary or many, soft or hard, painful or painless, depending on the reason. They may grow quickly or stay the same size for a long time.

Local infectious causes of lumps might manifest as boils or abscesses. Bug bites to severe traumas, such as bone fractures, can result in blood clots in the tissues, which can generate knee lumps (hematoma). Also, knee lumps are a major risk factor for a meniscus tear.

Tumors of the skin, soft tissues, or shinbone (tibia) can occasionally feel like lumps, both benign and malignant. A biopsy or surgical excision of the lump can be used to evaluate whether cancer is present in these circumstances. Cysts are fluid-filled sac-like structures that can occur in various regions of the body. They might feel lumpy. Baker’s cyst is a collection of fluid on the back of the knee.

What does a lump on a knee feel like?

You may feel bruising of the knee lumps. This occurs as a result of internal bleeding within the lump. You will notice skin darkening and pain at the site of the knee lump if the blood vessels in the knee lump rupture.

Your knee joint will be distorted and you will be unstable while walking if the knee lump is hard and firm. It also puts pressure on the muscles and tendons, making it difficult to walk and run properly. You should consult a doctor right now to correct the situation.

On the surface of the knee lump and in the surrounding area, you will notice redness and warmth. This is a symptom that the knee lump is inflamed. Apply topical treatments or take them orally if the region is irritated.

If the knee lump is due to a knee injury, you should seek professional medical advice from orthopaedic doctor. X-rays and other diagnostic procedures are done if the range of motion is reduced to avoid future knee problems or any serious condition.

Causes of knee lump

Bursitis(1) is a medical condition in which the bursa becomes inflamed. A bursa is a fluid-filled sac that cushions a joint and allows it to move freely. Bursitis of the kneecap occurs when the bursa between the front of the kneecap and the skin becomes inflamed. Kneeling for an extended period of time can result in kneecap bursitis, which manifests as an egg-shaped bulge on the front of the kneecap.

Gout can cause a bump to form on your knee. It’s a condition in which uric acid crystals build up in your joints and cause inflammation. Swelling develops at the site of the inflammation, resulting in a hump on the skin. This kind of bump hurts, and you’ll require therapy to get rid of the discomfort and inflammation.

Rheumatoid arthritis(2) is a chronic autoimmune disease of the knee joint that causes nodules or lumps on the joint. In this illness, your body damages its own joints, resulting in skin pimples. Osteoarthritis develops if your joint ligaments are damaged which results in knee swelling.

Benign tumors can also show up on your skin as lumps that are hard and stiff to the touch. The majority of the time, these masses do not produce any systemic symptoms. A fibroma is a tumor-like development consisting largely of fibrous or connective tissue that is benign. Uncontrolled cell proliferation occurs for unexplained reasons, or as a result of injury or local irritation, resulting in tumor-like growths like fibroma. Fibromas can appear anywhere on the body and are rarely treated or removed.

Types of lumps on the knee


Warts are tiny, rough, spherical growths on the top layer of the skin that are sometimes known as common warts or verrucae. They can be found individually or in groups. The human papillomavirus (HPV) causes common warts(3), which are spread through direct contact, often through a breach in the skin. They can be transmitted from one part of the body to another merely by touching.

Warts can affect anyone, but they are more common in people who have a weaker immune system as a result of sickness or chemotherapy. Warts can affect children and teenagers as well.

Synovial chondromatosis

Synovial chondromatosis is a condition that affects the synovium, a thin flexible membrane that encloses the synovial fluid in the joint. It’s easy to mix it up with tendonitis and arthritis. Joint swelling, discomfort in one knee, pain in one hip, swollen knee, and spontaneous knee pain are some of the most common symptoms.

Skin cyst

A cyst is a tiny sac or lump that grows in the body for no obvious cause and is filled with fluid, air, fat, or other material. A skin cyst is a cyst that develops just beneath the surface of the skin. Skin cysts form when keratinocytes – the cells that make up the skin’s relatively strong outer layer – become trapped.

A skin cyst can affect anyone, although it is more common in people over the age of 18, those who have acne, and those who have had their skin harmed.

Dermatofibroma lumps on a knee

A dermatofibroma is a type of skin growth that typically develops on the lower legs but can occur anywhere on the body. These mole-like growths are completely harmless (noncancerous.)

Although the aetiology is unknown, dermatofibroma can develop after a minor injury. The growths aren’t infectious. A hard, elevated growth that is red, pink, or brown and less than half an inch wide is one of the symptoms. They’re normally harmless, but they might be sensitive or irritating, and they come in groups or alone.

Baker’s cyst (popliteal cyst)

A Baker’s cyst(4), also known as a Popliteal cyst, is a fluid-filled lump behind the knee that creates a protrusion and tightness. When the knee is fully flexed or extended, the pain can become more severe.

Although a Baker’s cyst can cause swelling and discomfort, treating the underlying disease (such as knee arthritis) usually alleviates the symptoms. Your doctor will be able to tell you if surgery is necessary, which is unlikely.

Osgood Schlatter

This can occur when the lower aspect of the patella tendon pulls on its attachment into the tibia.

A photo of a lump on a knee

Care and treatment for a lump on a knee

Following are the treatment options if you have knee swelling:

  • For 10 to 20 minutes at a time, apply ice or a cold pack to your kneecap. Place a small towel between your skin and the ice.
  • After three days of ice, you can apply heat to your kneepads. You can use a warm, moist towel, a hot water bottle, or a low-heat heating pad.
  • When icing the injured leg or sitting or lying down for the following three days, prop it up on a pillow. Try to maintain it above your heart’s level. This will aid in the reduction of oedema.
  • Allow your knee to rest. Put an end to any hobbies that give you pain. Change your activities to ones that are less taxing on your knee.
  • Take your medications exactly as directed by your doctor. If you think you’re having a problem with your medicine, call your doctor or the nurse hotline.
  • Ask your doctor if you can use acetaminophen (Tylenol), ibuprofen (Advil, Motrin), or naproxen (Naprosyn) as an over-the-counter pain reliever (Aleve). You can also use steroids(5) like cortisone to eliminate inflammation rapidly.


A lump on the knee represents a tumor or any other soft tissue defect. If this is painful, you will feel difficulty walking. You should also worry about it even if the knee lump is not painful. You need to see your doctor if the knee lump does not reduce by itself. If you have a medical history of knee lumps, you should consult a healthcare provider for physical examination and health information.

Frequently asked questions

What can a lump on your knee mean?

A knee lump can be a deformity caused by a chronic inflammatory condition like arthritis, or it can be a deformity caused by any type of joint damage.

Is knee bursitis a hard lump?

Bursae, small squishy sacs that surround your joints, become inflamed. It’s possible that you’ll feel stiff and that moving the joint normally will cause pain. Despite the fact that it is linked to particular accidents and diseases, the exact cause of each occurrence is frequently unknown. It could be a short-term difficulty or a long-term issue. Drugs, physical therapy, and lifestyle modifications can all be used by your doctor to help you treat it.

What do Baker’s cysts look like?

A Baker’s cyst is a fluid-filled cyst behind your knee that causes a bulge and tightness. When you fully flex or extend your knee, or when you’re active, the discomfort can get worse. 

How do you reduce swelling on the side of your knee?

Inflammation is indicated by swelling on the side of the knee. To reduce swelling, you should take anti-inflammatory medications such as ibuprofen and naproxen. If the swelling doesn’t go away, talk to your doctor about it.

What is the lump on the outside of my knee?

A meniscal cyst is most often a bump on the outside of the knee. A meniscal cyst is a collection of viscous fluid that develops when the meniscal cartilage, which cushions the knee, tears.

What is a housemaid’s knee?

The prepatellar bursa is a tiny fluid-filled sac that resides beneath the skin, above the patella, and on the front of the knee (kneecap). Bursitis is characterized by a large and painful prepatellar bursa, which is known as Housemaid’s knee(6).

Does fluid on the knee go away by itself?

The fluid in the swelling goes away once the source of the swollen joint is treated. Fluid on the knee, on the other hand, does not always go away. Treatment for many illnesses consists of managing your symptoms rather than eradicating them.


  1. Four Common Types of Bursitis: Diagnosis and Management : JAAOS – Journal of the American Academy of Orthopaedic Surgeons. (2019). LWW. https://journals.lww.com/jaaos/Abstract/2011/06000/Four_Common_Types_of_Bursitis__Diagnosis_and.6.aspx
  2. Gabriel, S. E. (2001). THE EPIDEMIOLOGY OF RHEUMATOID ARTHRITIS. Rheumatic Disease Clinics of North America, 27(2), 269–281. https://doi.org/10.1016/s0889-857x(05)70201-5
  3. Gross, G., Pfister, H., Hagedorn, M., & Gissmann, L. (1982). Correlation between Human Papillomavirus (HPV) Type and Histology of Warts. Journal of Investigative Dermatology, 78(2), 160–164. https://doi.org/10.1111/1523-1747.ep12506324
  4. Validate User. (n.d.). Academic.oup.com. Retrieved May 30, 2022, from https://academic.oup.com/cid/article/29/2/276/274211?login=true
  5. Kruse, D. W. (2008). Intraarticular cortisone injection for osteoarthritis of the hip. Is it effective? Is it safe? Current Reviews in Musculoskeletal Medicine, 1(3-4), 227–233. https://doi.org/10.1007/s12178-008-9029-0

Martyn, R. W. (1861). Treatment of “Housemaid’s Knee.” British Medical Journal, 2(47), 565. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2288112/

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