The knee area has numerous bursae and fat pads, whose main role is to reduce friction between the bone and ligaments or tendons, and between the skin and patella. Knee bursitis is often seen in the pre-patellar bursa. The main function of a pre-patellar bursa is to separate the patella from the patellar tendon and the overlying skin, thereby reducing friction on movement and allowing a maximal range of joint movement. However, the superficial nature of the patellar bursa renders it susceptible to injury and secondary inflammation.
Bursitis means inflammation within a bursa, which is a small sac of fluid with a thin lining. There are some bursae in the body. Bursae are usually found around joints and in places where ligaments and tendons pass over bones. They can also be located at other locations if there has been significant pressure or friction imposed on that area.
The role of the bursa is to reduce friction and allow a maximal range of motion around joints. When there is inflammation of a bursa (bursitis), the bursa swells due to an increase of fluid within the bursa sac.
Possible causes of knee bursitis
- Acute direct trauma sustained from a fall or direct blow to the patella during sports
- Diabetes mellitus, prolonged use of alcohol, uremia or chronic obstructive pulmonary disease
- Infection, commonly by Staphylococcus aureus, caused by abrasion, laceration or penetrating wound
- Inflammation as a part of systemic inflammatory processes such as rheumatoid arthritis or a crystal deposition disease such as gout
- Recurrent minor trauma caused by excessive kneeling in occupations such as carpet layer, coal miner, electrician, homemaker, plumber, roofer
Knee Bursitis Symptoms
- Swelling of the kneecap (over, above or below)
- Decreased movement of the knee
- Warmth and at the site of the bursa
- Pain during knee movement
Activities such as kneeling, crouching, and repetitive bending may aggravate the symptoms. Sitting still can help relieve them. Knee bursitis swelling is within the bursa and not the knee joint. People often assume that any swelling of the knee joint is due to joint issues, but there is a significant difference between fluid accumulation within the bursa and the knee joint.
It is, therefore, important for you to see one or more orthopedic specialist to become sure about the exact cause of the swelling. It always helps to take a medical opinion from another expert to further confirm the condition.
Diagnosis of knee bursitis
Physical examination of the knee
- A doctor performs a physical examination to detect warmth, swelling and the source of pain.
- Carefully moves legs and knees in different positions to determine the range of motion of knee joint and identify movement associated with pain.
- X-rays: X-rays may be useful in revealing a bone fracture, tumor or arthritis.
- MRI: through MRI doctor can see detailed images of structures (soft tissues ex: bursa) within your body.
- It helps the doctor to visualize the extent of swelling in the affected bursa.
Depending on the affected knee joint, your doctor may recommend a suitable treatment approach.
If knee bursitis is due to an infection, the doctor may prescribe a course of antibiotic treatment.
The doctor may refer you to a physiotherapist who can help you learn appropriate exercises to improve flexibility and strengthen muscles. It may assist you in reducing your risk of recurring episodes of knee bursitis.
Surgical and other procedures
Invasive treatment options for knee bursitis treatment:
- Corticosteroid injections: If the bursitis is persistent and not responding to conservative treatments, the doctor may suggest a corticosteroid drug injection directly into an affected bursa to reduce pain and inflammation. The inflammation usually subsides, but you may experience pain and swelling from the injection for a couple of days.
- Aspiration: The doctor may aspirate a bursa to reduce excess fluid and treat inflammation. He or she inserts a needle directly into the affected bursa and draws the fluid out. Fluid aspiration may cause short-term pain and swelling. A knee immobilizer may be required for a short period after the injection to reduce the chance of recurrent swelling.
- Surgery: If you have severe chronic knee bursitis, and it does not respond to other treatments, your doctor may recommend that the bursa is removed surgically.
Knee bursitis is best prevented by avoiding direct blows to the kneecap area and by avoiding prolonged kneeling. In such cases, you should use thick knee pads or foam cushions. Knee pads should especially be used by people who have already had an episode of housemaid’s knee, to prevent it from coming back.
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