Swollen Knee Causes and Treatment

Table of ContentsView AllTable of ContentsSymptomsCausesDiagnosisTreatment

Table of ContentsView All

View All

Table of Contents

Symptoms

Causes

Diagnosis

Treatment

Removing the fluid may also reduce pain and stiffness. Once the underlying cause is found, treatment can be administered. This may involve rest, knee immobilization, antibiotics, painkillers, steroid injections, and possibly surgery.

This article looks at the symptoms and causes of a swollen knee, including how the underlying cause is diagnosed and treated.

Verywell / Brianna Gilmartin

Swollen Knee Symptoms

A knee effusion can vary in severity and, depending on the underlying cause, may involve:

In some cases, fluids seeping from the joint space can form a fluid-filled sac on the back of the knee called aBaker’s cyst(popliteal cyst). A Baker’s cyst is painless and often feels like a water-filled balloon. However, if the cyst break opens, there may be pain, swelling, and bruising.

Knee Effusion or Edema?

Edema can occur alongside knee effusion as inflammation in the joint space causes fluids to build the overlying tissues of the knee, making the skin look and feel spongy.

Peripheral edema can cause puffiness, warmth, and a feeling of heaviness, typically without pain. Both knees are generally affected.

When to Seek Urgent Care

Causes of Knee Pain and Treatment Options

What Causes Knee Swelling?

The causes of knee effusion can be broadly categorized as traumatic injuries, overuse injuries, infections, inflammatory conditions, and tumors.

The knee is comprised of many different tissues and structures, including:

Knee effusion can occur when any of these structures are damaged, infected, or diseased.

Traumatic Injury

A traumatic injury like a blow to the knee, a crush injury, a severe fall, or the twisting of the knee can damage the knee and cause effusion.

Examples include:

Overuse Injury

Overuse injuries, also known as repetitive use injuries, are those in which long-time stress on a joint causes inflammation, pain, and the loss of joint movement. Overuse knee injuries are commonly associated with sports like running or occupations that require heavy lifting or squatting.

Infections

These most commonly include:

Inflammatory Conditions

Many of the inflammatory conditions affecting the knee areautoimmune, meaning that the immune system mistakenly targets normal tissues with inflammation. Other conditions cause knee inflammation due to knee joint deterioration, causing bone to rub against bone.

Tumors

These include:

The first step in treating aneffusionis to pinpoint the cause. Your healthcare provider will first review your medical history, including recent accidents or history of trauma, and conduct a physical exam.

The physical exam can reveal a lot about the underlying cause. For instance, when the swelling is within the knee joint, the kneecap will usually be well-defined and easily felt under the skin (although it may seem pushed out). When the swelling is in the overlying soft tissues, the kneecap may hidden beneath the swelling.

A “straight leg raise” may also be performed in which you sit on an examining table and straighten your leg as far as you can. The range of motion of the knee (or lack of) can suggest whether an acute injury or other disease mechanism is involved.

Based on the outcome of the physical exam, the healthcare provider may order different tests and procedures, including:

How to Treat Knee Swelling

The treatment of knee swelling varies based on the underlying cause, whether it be an injury, infection, inflammatory condition, or tumor.

RICE Protocol

Aknee braceand a mobility device like a pair of crutches may be needed if the injury is severe.Physical therapymay be recommended to restore strength and range of motion after an injury, fracture, or period of prolonged immobilization.

Medications

Different medications may be prescribed to treat different causes of knee swelling. These include:

Other drugs may be prescribed to manage chronic conditions, such asdisease-modifying antirheumatic drugs (DMARDs)used for the treatment of autoimmune diseases like lupus or rheumatoid arthritis.

Surgery

Surgery to fully restore function to the knee after a fracture or the rupture of a knee tendon or ligament. The surgery can take two forms:

Summary

12 SourcesVerywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.Gupte C, St Mart JP.The acute swollen knee: diagnosis and management.J R Soc Med.2013 Jul;106(7):259–68. doi:10.1177/0141076813482831Bronstein RD, Schaffer JC.Physical examination of the knee: meniscus, cartilage, and patellofemoral conditions.J Am Acad Orthop Surg. 2017;25(5):365-374. doi:10.5435/JAAOS-D-15-00464Herman AM, Marzo JM.Popliteal cysts: a current review.Orthopedics. 2014;37(8):e678-e684. doi:10.3928/01477447-20140728-52Besharat S, Grol-Prokopczyk H, Gao S, Feng C, Akwaa F, Gewandter JS.Peripheral edema: a common and persistent health problem for older Americans.PLoS ONE. 2021;16(12):e0260742. doi:10.1371/journal.pone.0260742American Academy of Orthopaedic Surgeons.Common knee injuries.Jarraya M, Roemer FW, Hayashi D, Crema MD, Guermazi A.Overuse-related injuries of the knee.Radiol Clin North Am.2023 Mar;61(2):249-259. doi:10.1016/j.rcl.2022.10.004Neto FA, Teixeira MJD, do Carmo Araujo LH, Ponte CEB.Knee bone tumors: findings on conventional radiology.Radiol Bras.2016 May-Jun;49(3):182–189. doi:10.1590/0100-3984.2013.0007University of Michigan Health.Rest, ice, compression, and elevation (RICE).Jones BQ, Covey CJ, Sineath MH.Nonsurgical management of knee pain in adults.Am Fam Physician.2015;92(10):875-883Fraenkel L, Bathon JM, England BR, et al.2021 American College of Rheumatology guideline for the treatment of rheumatoid arthritis.Arthritis Care Res. 2021;73(7):924-939. doi:10.1002/acr.24596American Academy of Orthopaedic Surgeons.Fractures (broken bones).American Academy of Orthopaedic Surgeons.Knee arthroscopy.

12 Sources

Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.Gupte C, St Mart JP.The acute swollen knee: diagnosis and management.J R Soc Med.2013 Jul;106(7):259–68. doi:10.1177/0141076813482831Bronstein RD, Schaffer JC.Physical examination of the knee: meniscus, cartilage, and patellofemoral conditions.J Am Acad Orthop Surg. 2017;25(5):365-374. doi:10.5435/JAAOS-D-15-00464Herman AM, Marzo JM.Popliteal cysts: a current review.Orthopedics. 2014;37(8):e678-e684. doi:10.3928/01477447-20140728-52Besharat S, Grol-Prokopczyk H, Gao S, Feng C, Akwaa F, Gewandter JS.Peripheral edema: a common and persistent health problem for older Americans.PLoS ONE. 2021;16(12):e0260742. doi:10.1371/journal.pone.0260742American Academy of Orthopaedic Surgeons.Common knee injuries.Jarraya M, Roemer FW, Hayashi D, Crema MD, Guermazi A.Overuse-related injuries of the knee.Radiol Clin North Am.2023 Mar;61(2):249-259. doi:10.1016/j.rcl.2022.10.004Neto FA, Teixeira MJD, do Carmo Araujo LH, Ponte CEB.Knee bone tumors: findings on conventional radiology.Radiol Bras.2016 May-Jun;49(3):182–189. doi:10.1590/0100-3984.2013.0007University of Michigan Health.Rest, ice, compression, and elevation (RICE).Jones BQ, Covey CJ, Sineath MH.Nonsurgical management of knee pain in adults.Am Fam Physician.2015;92(10):875-883Fraenkel L, Bathon JM, England BR, et al.2021 American College of Rheumatology guideline for the treatment of rheumatoid arthritis.Arthritis Care Res. 2021;73(7):924-939. doi:10.1002/acr.24596American Academy of Orthopaedic Surgeons.Fractures (broken bones).American Academy of Orthopaedic Surgeons.Knee arthroscopy.

Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.

Gupte C, St Mart JP.The acute swollen knee: diagnosis and management.J R Soc Med.2013 Jul;106(7):259–68. doi:10.1177/0141076813482831Bronstein RD, Schaffer JC.Physical examination of the knee: meniscus, cartilage, and patellofemoral conditions.J Am Acad Orthop Surg. 2017;25(5):365-374. doi:10.5435/JAAOS-D-15-00464Herman AM, Marzo JM.Popliteal cysts: a current review.Orthopedics. 2014;37(8):e678-e684. doi:10.3928/01477447-20140728-52Besharat S, Grol-Prokopczyk H, Gao S, Feng C, Akwaa F, Gewandter JS.Peripheral edema: a common and persistent health problem for older Americans.PLoS ONE. 2021;16(12):e0260742. doi:10.1371/journal.pone.0260742American Academy of Orthopaedic Surgeons.Common knee injuries.Jarraya M, Roemer FW, Hayashi D, Crema MD, Guermazi A.Overuse-related injuries of the knee.Radiol Clin North Am.2023 Mar;61(2):249-259. doi:10.1016/j.rcl.2022.10.004Neto FA, Teixeira MJD, do Carmo Araujo LH, Ponte CEB.Knee bone tumors: findings on conventional radiology.Radiol Bras.2016 May-Jun;49(3):182–189. doi:10.1590/0100-3984.2013.0007University of Michigan Health.Rest, ice, compression, and elevation (RICE).Jones BQ, Covey CJ, Sineath MH.Nonsurgical management of knee pain in adults.Am Fam Physician.2015;92(10):875-883Fraenkel L, Bathon JM, England BR, et al.2021 American College of Rheumatology guideline for the treatment of rheumatoid arthritis.Arthritis Care Res. 2021;73(7):924-939. doi:10.1002/acr.24596American Academy of Orthopaedic Surgeons.Fractures (broken bones).American Academy of Orthopaedic Surgeons.Knee arthroscopy.

Gupte C, St Mart JP.The acute swollen knee: diagnosis and management.J R Soc Med.2013 Jul;106(7):259–68. doi:10.1177/0141076813482831

Bronstein RD, Schaffer JC.Physical examination of the knee: meniscus, cartilage, and patellofemoral conditions.J Am Acad Orthop Surg. 2017;25(5):365-374. doi:10.5435/JAAOS-D-15-00464

Herman AM, Marzo JM.Popliteal cysts: a current review.Orthopedics. 2014;37(8):e678-e684. doi:10.3928/01477447-20140728-52

Besharat S, Grol-Prokopczyk H, Gao S, Feng C, Akwaa F, Gewandter JS.Peripheral edema: a common and persistent health problem for older Americans.PLoS ONE. 2021;16(12):e0260742. doi:10.1371/journal.pone.0260742

American Academy of Orthopaedic Surgeons.Common knee injuries.

Jarraya M, Roemer FW, Hayashi D, Crema MD, Guermazi A.Overuse-related injuries of the knee.Radiol Clin North Am.2023 Mar;61(2):249-259. doi:10.1016/j.rcl.2022.10.004

Neto FA, Teixeira MJD, do Carmo Araujo LH, Ponte CEB.Knee bone tumors: findings on conventional radiology.Radiol Bras.2016 May-Jun;49(3):182–189. doi:10.1590/0100-3984.2013.0007

University of Michigan Health.Rest, ice, compression, and elevation (RICE).

Jones BQ, Covey CJ, Sineath MH.Nonsurgical management of knee pain in adults.Am Fam Physician.2015;92(10):875-883

Fraenkel L, Bathon JM, England BR, et al.2021 American College of Rheumatology guideline for the treatment of rheumatoid arthritis.Arthritis Care Res. 2021;73(7):924-939. doi:10.1002/acr.24596

American Academy of Orthopaedic Surgeons.Fractures (broken bones).

American Academy of Orthopaedic Surgeons.Knee arthroscopy.

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