Joint Effusion: Definition, Causes, Symptoms & Treatment

Lesson Transcript
Joshua Bowles

Joshua is a Sports Medicine and Athletic Training Instructor and has a Master's degree in Kinesiology.

Expert Contributor
Christianlly Cena

Christianlly has taught college physics and facilitated laboratory courses. He has a master's degree in Physics and is pursuing his doctorate study.

Joint effusion is a medical condition where the space between the bones of a joint accumulates excess fluid. Explore the characteristics of this disorder, its causes, common symptoms, and surgical and non-surgical treatment options. Updated: 01/18/2022

What Is Joint Effusion?

Did you ever fill up balloons with water on a hot summer day in your childhood? When you tied off those balloons, do you remember the way they felt? You could definitely tell that those balloons were heavy with fluid.

The same is true for our joints. When an injury occurs that causes fluid to build up, it feels much like a firm water balloon would.

A joint is a space where two or more bones come together, known as an articulation. In joint effusion, the term ''effusion'' simply refers to an excessive amount of fluid that accumulates within a joint space.

This only applies to synovial joints (as opposed to fibrous or cartilaginous joints, which involve little to no movement). These are the ones you usually associate with the bendable parts of the body, like in the elbow, shoulder, knee, hip, and wrist.

All synovial joints have fluid already positioned in the joint space to help lubricate and protect the bones in that space. When an injury or an issue occurs that causes inflammation, more fluid is pushed into the joint space.

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  • 0:04 What Is Joint Effusion?
  • 1:08 Causes of Joint Effusion
  • 1:58 Symptoms of Joint Effusion
  • 2:26 Treatment for Joint Effusion
  • 3:49 Lesson Summary
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Causes of Joint Effusion

Generally speaking, the main causes of joint effusion are inflammation and trauma. One of the more common causes is arthritis, which is inflammation of the joint leading to a deterioration of the articulating aspects of the bone.

Trauma in the form of ligament or tendon injury can also lead to effusion, as damaged tissues can cause bleeding and swelling within the joint space. Overuse of a joint, say from sports, gardening, workout routines, etc. can also be a cause.

Another common potential cause is bursitis, which is an inflammatory condition of the bursa sac, a fluid-filled, protective sac that's found in many joints throughout the body. In the case of bursitis, excess inflamed fluid fills up the bursae and can potentially lead to joint effusion.

Symptoms of Joint Effusion

Joint effusion causes pain, stiffness, and moderate to severe swelling and can present other inflammatory symptoms like redness and heat as well. Because the joint space fills up with an excess of fluid, the area will feel tight and full. This can make it difficult and uncomfortable to move that joint.

In some severe cases or cases that are left untreated, joint effusion can lead to an infection that can lead to other more serious conditions.

Treatment for Joint Effusion

In some mild cases of joint effusion, rest can be enough to treat the condition, particularly in cases where the cause is overuse of the joint. However, in many trauma or inflammation cases, more treatment options may be needed.

In trauma situations, the injured structures need to be repaired. This should correct the problem that causes the joint effusion. The remaining fluid will sometimes be reabsorbed back into the body. However, in most cases, aspiration of the joint is necessary, a procedure called arthrocentesis. This word is derived from Greek, meaning ''to puncture the joint.''

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Additional Activities

Joint Effusion: A Case Study

In this activity, you'll check your knowledge regarding the causes, symptoms, and treatment of joint effusion.


For this activity, print or copy this page on a blank piece of paper. Then, carefully read each of the given scenarios and provide a written response to the questions that follow.

Case 1

Mitch has severe pneumonia, a bacterial infection that causes inflammation of the lungs. In her case, the air sacs in both her lungs have already been infected. Mitch's medical records indicate excess fluid in the lung cavity. The excess fluid has resulted in Mitch having a high fever, chills, and difficulty breathing. The excess fluid within her lungs was immediately drained out to prevent further complications.

Case 2

Nico, a 50-year-old, presents to a nearby hospital with a 5-day history of gradually worsening pain, stiffness, and swelling of his right wrist and left ankle. These affected areas were found to contain excessive amounts of fluid, which hindered Nico from doing his daily routine. He denied drinking alcohol, smoking cigarettes, or using any recreational drugs. His medical records showed that he has arthritis, a medical condition that involves the deterioration of the articulating aspects of the bone.


  1. What are the most striking clinical findings for both patients?
  2. Does Mitch and Nico experience effusion? Why do you say so?
  3. Identify the cause for each patient's effusion (if applicable).
  4. Identify which patient has a joint effusion (if applicable).
  5. Would aspiration of the joint and the lungs be helpful in treating effusion? Explain your answer.

Sample Answers

  1. Pneumonia and the excess fluid in the lung cavity are Mitch's most striking clinical findings. For Nico, it was the worsening pain and swelling of his right wrist and left ankle.
  2. Yes, both of them are experiencing effusion. By definition, effusion is an abnormal collection of fluid in hollow spaces in bones or between tissues of the body.
  3. Mitch's effusion is caused by a bacterial infection brought about by pneumonia. For Nico, the effusion is most-likely caused by arthritis.
  4. Nico has a joint effusion.
  5. Aspiration of the affected area is necessary to ensure that effusion does not lead to more serious conditions. In both cases, the affected regions are punctured and the fluid is drained. The obtained fluid is sampled for infection.

Medical Disclaimer: The information on this site is for your information only and is not a substitute for professional medical advice.

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