What is Knee Bursitis?
Bursitis comes from combining the words bursa and + “itis,” a suffix used in medicine to imply inflammation. A bursa is a fluid-filled pouch that cushions the moving parts [muscles, tendons, ligaments, and skin]in the joint to reduce rubbing and friction. Bursitis commonly affects major joints overused or used repetitively, like the shoulders, elbows, hips, and knees.
The knee has four major bursae that often get inflamed:
- Prepatellar bursa: the bursa at the front of the knee, which is sandwiched between the knee’s skin and the kneecap (called the patella)
- Infrapatellar bursa: the bursa below the kneecap beneath the tendon of a muscle that attaches the front of the thigh and kneecap to the upper part of the shin bone
- Anserine bursa: the bursa found inside the knee, between the shinbone and the three tendons of the hamstrings
- Suprapatellar bursa: the bursa on top of the kneecap allows free movement of the muscle at the front thigh.
Prepatellar bursitis, also known as housemaid’s knee, results from prolonged kneeling and repetitive minor trauma or a strong, impactful blow to the knee’s front part.
Aside from friction, infrapatellar bursitis can be caused by overuse, especially jumping. It usually happens in conjunction with jumper’s knee or patellar tendonitis.
Anserine bursitis is often due to overuse associated with running. It is common in people who are obese as well as those with osteoarthritis.
Suprapatellar bursitis occurs due to a direct blow or repetitive motion of the quadriceps muscle, the big muscle at the front thigh.
Signs and Symptoms
A person with bursitis will see and feel will depend on the inflamed bursa’s location and what caused it. Symptoms will appear rapidly in case of direct trauma. But in bursitis caused by irritation and friction due to overuse and strenuous activity, signs and symptoms gradually appear.
Here are the most common symptoms:
- Presence of a small lump under the knee’s skin [but outside the joint]
- Warm and tender to touch
- Pain when moving or sometimes even at rest
- If due to an infection, signs of infection such as fever, chills, and fatigue may be present; pus may also form in the bursa.
- Limited range of motion due to swelling and/or pain
What are the Causes of Knee Bursitis?
- Repetitive movements. Knee bursitis is most frequently caused by repetitive motion, overuse, and prolonged sustained positions.
- Direct Blow. It can also be due to direct trauma such as direct blows caused in contact sports like wrestling and football. The bursa may fill with blood due to injury.
- Infection. It can be caused by a bacterial infection (called septic or infectious bursitis) when a scrape, punctured wound, or insect bite breaks the skin. While not very common, this type of bursitis is serious and needs urgent treatment.
- Other Underlying Conditions. Bursitis can also be caused by crystal deposits from gout or pseudogout and other conditions such as rheumatoid arthritis and diabetes.
- History of Bursitis. Those who have had bursitis before are likely to have them again.
- Underlying condition. Conditions such as osteoarthritis, gouty arthritis, and rheumatoid arthritis often cause swelling in the joint. Crystal deposits and autoimmune attacks might lead to inflammation of the joint, including the bursae.
- Certain occupations. Work that entails prolonged kneeling and repetitive movements increases the chance of the person getting bursitis. This includes clergypersons, runners, hikers, and athletes.
- Being overweight and old age increases the risk of developing Bursitis.
History and Physical Exam
A doctor will take your history by asking questions about the symptoms you are experiencing, their location, intensity (pain level), and how long they have been present.
You will also be asked for risk factors such as being active in sports, or your occupation, which may increase your chance of having bursitis. The doctor will also inspect and do a simple physical exam to check for the available range of motion in the knee and pain.
Your doctor may request tests to rule out other causes and confirm the diagnosis. Imaging methods such as CT scans, X-rays, and MRI can help check for fractures and soft tissue injuries.
A sample will be taken from the bursa by removing excess fluid using aspiration (called Bursal aspiration) for analysis. In addition to testing the sample to detect possible infection, aspiration also relieves the bursa’s pressure.
Treatment and Home Remedies
The treatment for bursitis largely depends on the cause as well as the symptoms.
Bursitis Caused by Infection
For septic or infectious bursitis, the doctor will perform a further evaluation to determine the course of treatment. The doctor may prescribe antibiotic treatment, recommend repeated aspiration or surgical drainage. The doctor may also recommend surgical removal of the infected bursa (bursectomy).
- Activity Modification. Avoid activities that cause pain and stress on the joint. Opt for low-impact exercises and other light activities until bursitis clears up.
- RICE. Rest your knee. Apply ice every 20 minutes for three to four days. Use cooling wraps or soft cushion pads to provide support and light compression on the joint. Elevate your leg when possible (above the level of the heart).
- Take medications. Manage pain with non-steroidal anti-inflammatory drugs (NSAIDs) like ibuprofen. These medications help reduce pain and swelling.
If these measures do not reduce pain or other symptoms, your doctor may recommend aspiration or surgical drainage, a corticosteroid to reduce inflammation or bursectomy of the chronically inflamed bursa.
Is it Possible to Prevent Knee Bursitis?
While bursitis can happen to anyone, there are some ways to reduce the risk of getting one. If you think that you have a high chance of developing bursitis, here are some things that you can do:
- Take care of your knee joint. If possible, try to prevent repetitive bending to reduce the pressure on the knee joint. Try to achieve an ideal weight to reduce the stress and load on the knee joint.
- Take breaks. If you anticipate working for prolonged hours in kneeling or are likely to make repetitive motions, include a few minutes of rest and stretching every few minutes.
- Wear knee protection. When hiking, running, or participating in sports, wear knee pads to help support and protect the joint. The same is true for occupations that require prolonged kneeling.
- Work-out and Play with Your Knees in Mind. Before working out, do proper stretches and warm-up. Make sure to use proper form and avoid sticking with just one motion. Mix things up to avoid putting undue stress on the joint.