What is bursitis?
A bursa is a small, fluid-filled sac that acts as a cushion between a bone and other tissue like tendon, muscle or skin, which reduces friction between these structures. Bursas are found throughout the body. When swollen, these cause a painful condition known as bursitis. Though the most common locations for bursitis are shoulder, hip and elbow (olecranon), it may also occur in the knee, heel (retrocalcaneal) and base of the big toe.
Knee bursitis refers to the inflammation of a bursa near the knee joint. Each knee has 11 bursae and any of these can become inflamed. Knee bursitis causes pain and limits mobility. Types of knee bursitis include:
- Prepatellar bursitis (Housemaid’s knee) is the inflammation of bursa in front of the patella (kneecap) when it becomes irritated and produces excess fluid.
- Infrapatellar bursitis is the inflammation of the infrapatellar bursa located just below the kneecap. It is common among people whose work involves kneeling on firm surfaces, and different names are given to this condition depending on the occupation. Infrapatellar bursitis can be deep or superficial:
- Superficial infrapatellar bursa (Clergyman’s knee) is located between the tibial tubercle and the overlying skin, and results from inflammation and fluid accumulation due to chronic stress.
- Deep infrapatellar bursitis occurs between the posterior aspect of the patellar tendon and the tibia, and is located between the posterior portion of the patellar tendon and the tibia. However, in adolescents, its symptoms must be differentiated from the Osgood–Schlatter disease.
- Semimembranosus bursitis (Baker’s Cyst or Popliteal Cyst) is found at the back of the knee, between a hamstring muscle (submembranous muscle) and a calf muscle (medial head of gastrocnemius).
- Suprapatellar bursa occurs below the kneecap, underneath the quadriceps tendon at the base of thigh.
- Pes anserine bursitis is common among runners. The bursa occurs on the inner side of the knee.
What are the causes of the disorder?
Common reasons for bursitis are:
- Overuse, sudden change in activity levels
- Rheumatoid arthritis, gout, infection
Bursitis of the knee is mostly caused by:
- Frequent and sustained pressure on knees, like occupational kneeling (plumbers, gardeners, clergy, housemaids, etc. are at an increased risk)
- Trauma to the knee
- Bacterial infection of bursa
- Frequent falls on the knee
- Complications of rheumatoid arthritis, obesity, osteoarthritis or gout
- Impaired immune system – People who take medication that makes them more susceptible to infection are at a greater risk of septic knee bursitis (conditions include diabetes, cancer, alcoholism, HIV/AIDS)
What one needs to know about symptoms or signs?
Symptoms of knee bursitis can vary depending on the bursa that is affected. General signs include:
- The affected area feels warm to touch
- Swelling in the area
- Pain or tenderness when one moves or applies pressure
The symptoms may be seen instantly in case of trauma to the knee, but most cases of knee bursitis develop from repeat injuries that are sustained as part of a person’s occupation, and symptoms usually develop gradually or worsen with time.
Which specialist should be consulted in case of signs and symptoms?
A person suspecting knee bursitis must consult a rheumatologist, a doctor who specializes in arthritis and joint disorders, or an orthopaedic surgeon.
What are the screening tests and investigations done to confirm or rule out the disorder?
Knee bursitis may be diagnosed through:
- Physical examination – The doctor examines the affected region and asks questions regarding symptoms, job type, and hobbies the person follows regularly or any recent trauma suffered on the joint.
- Fluid sample aspiration – The doctor may extract a sample fluid from the affected bursa using a fine needle, a process known as aspiration. The sample is sent to a laboratory to be tested for bacterial infection (septic bursitis) or crystals (due to conditions like gout). A dressing is added later to cover the area.
- Blood tests – This is done to rule out other conditions like rheumatoid arthritis.
- Imaging tests – An x-ray can rule out broken bones while a magnetic resonance imaging (MRI) tests rules out tissue damage like a torn tendon.
What treatment modalities are available for management of the disorder?
Treatment options include:
- Medication – Medication for knee bursitis involves (a) corticosteroid injection directly into the affected bursa to counter inflammation and/or (b) antibiotics, if knee bursitis is due to an infection.
- Therapy – Knee bursitis therapies include:
- Physical therapy – A physical therapist or a specialist in sports medicine can guide a patient through certain exercises that help improve strength and flexibility of muscles, alleviate pain and reduce the risk of future episodes of bursitis.
- Aspiration – Aspiration involves removing excess fluid directly from the bursa using a fine needle to treat inflammation. However, there could be short-term pain and swelling.
- Surgery – In some cases, like when septic bursitis fails to respond to antibiotics, the doctor may conduct surgery. It involves either complete removal of the affected bursa or an incision in the skin to drain fluid out of the bursa.
What precautions or steps are necessary to stay healthy and happy during the treatment?
Patients can ease the pain and discomfort associated with knee bursitis by trying these self-care tips:
- Give the knee a rest – Discontinuing heavy activities and avoiding movements that may worsen the pain can help in the healing process.
- Ice application – An ice pack can be applied for 20 minutes, several times during the day to reduce pain.
- Compression – A compressive wrap or knee sleeve also reduces swelling.
- Knee elevation – Propping up the leg on pillows can reduce swelling in the knee.
How can the disorder be prevented from happening or recurring?
Preventive measures against knee bursitis involve the following:
- Protecting the joints – People whose jobs involve kneeling for long periods must wear a pair of kneepads. Those who walk or run regularly must wear proper shoes.
- Taking regular breaks – Tasks that involve repetitive movements of the knee must be carefully done to avoid placing excess strain on the tissue by taking adequate breaks in between and varying the pattern of physical activity.
- Warming up before exercise – Walking or jogging are good exercises to warm up with before starting more vigorous exercise.
- Strengthening muscles – Strong muscles can prevent future injuries or recurrence of bursitis.
“Bursae around the knee joints,” Indian J Radiol Imaging. 2012 Jan-Mar; 22(1): 27–30., Priyank S Chatra, https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3354353/
“Bursitis,” WebMD.com, https://www.webmd.com/pain-management/arthritis-bursitis
“Bursitis,” MayoClinic.com, Mayo Clinic Staff, https://www.mayoclinic.org/diseases-conditions/bursitis/basics/definition/con-20015102
“Bursitis,” NHS.uk, https://www.nhs.uk/Conditions/Bursitis/Pages/Introduction.aspx
“Bursitis,” MedlinePlus, NLM,NIH, https://www.nlm.nih.gov/medlineplus/ency/article/000419.htm
“Fast Facts About Bursitis And Tendinitis,” NIAMS.NIH.gov, National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS), https://www.niams.nih.gov/Health_Info/Bursitis/bursitis_ff.asp
“Knee bursitis,” MayoClinic.com, Mayo Clinic Staff, https://www.mayoclinic.org/diseases-conditions/knee-bursitis/basics/definition/con-20030816
“Prepatellar (Kneecap) Bursitis,” AAOS.org, American Academy of Orthopaedic Surgeons, https://orthoinfo.aaos.org/topic.cfm?topic=a00338