Housemaid’s Knee

What is Housemaid’s knee?

Prepatellar bursitis (housemaid’s knee, coal miner’s knee, carpet layer’s knee) is a  common type of inflammation in the kneecap (patella), characterized by swelling, pain and discomfort.¹ The patella has multiple fluid-filled sacs known as bursae; one type of bursa is known as the prepatellar bursa, which provides lubrication, thus allowing smooth movement, and reduces friction between the knee joints, bones, tendons and skin. Any inflammation leads to increase in the fluid (known as synovial fluid) production in the space in and around the bursa.² The other major knee bursae are the infrapatellar, suprapatellar, semimembranosus, and the pes anserine. 

Causes

The common causes are constant tension on the knee joint from persistent kneeling (in olden days, housemaids used to kneel whilst scrubbing floors, hence the name housemaid’s knee), being overweight, knee injuries, bacterial infection involving the prepatellar bursa and underlying joint problems like gout, rheumatoid arthritis and osteoarthritis.^2,3 

Risk factors

Any activities that involve prolonged kneeling have a higher chance of causing knee injuries. Professions such as carpet laying, carpentry, and plumbing, hobbies such as gardening and sports including volleyball, football, wrestling, and running can increase the risk of knee bursitis. Acute injury to the knee can lead to the bursal inflammation. Another risk factor of prepatellar bursitis is infection (septic bursitis) due to conditions such as diabetes, COPD, alcoholism, rheumatoid arthritis, gout and even certain medications which interfere with the immune system (eg. corticosteroids). People with a pre-existing history of knee bursitis are advised to wear adequate knee support gear.^2,4

Types

Based on the cause, prepatellar bursitis is differentiated into two types; septic and aseptic bursitis.

Septic prepatellar bursitis

This occurs due to a bacterial infection in the knee bursae. The symptoms usually appear more quickly and may be more severe, and fever is likely to be present. Septic prepatellar bursitis accounts for 30% of all cases of prepatellar bursitis.⁵ It is also more common in children and those with reduced immunity; those with diabetes, HIV, and those on long-term steroid treatment. The presence of infection can be confirmed by testing the synovial fluid (the fluid in and around the prepatellar bursa), sampled with a needle. Antibiotics would usually be required along with other treatment options. These can be taken orally in the form of solutions, tablets, or capsules.  If the symptoms do not subside or there is a risk of serious complications, hospital admission and intravenous antibiotics are advised.³

Aseptic prepatellar bursitis

This condition occurs when prepatellar bursitis is due to non-infective causes. Antibiotics are not usually required but may be prescribed if an infection is initially suspected.³

Symptoms

Symptoms usually appear gradually, but can be progress quickly if caused by knee injuries or accidents affecting the knee. There can be redness, swelling, pain and warmth in the affected knee, discomfort during knee movement and sometimes even during rest. In worse cases, it may cause an inability to move the affected knee. Fever may occur due to the inflammatory process accompanying prepatellar bursitis if it is of the septic type. If there is fever, you must visit the physician, who will analyse the symptoms and provide treatment.³

Diagnosis

The physician will diagnose prepatellar bursitis based on the history of symptoms and physical examination involving gentle movement of the affected knee in comparison to the other knee. Occasionally, they may also refer you for X-rays, an ultrasound scan, and an MRI of the affected knee, for a definite diagnosis and to provide management and care. In situations where other underlying medical conditions might be a cause, blood tests may also be necessary. ^2.5

If the physician suspects that the prepatellar bursa is infected, they will perform a procedure known as aspiration, in which a small amount of fluid is tested using a needle and syringe. Often, they might make a small cut through the skin of the knee, to let out some of the infected fluid in the knee joint. This procedure is known as incision and drainage.

Treatment

• The first line of treatment is rest. Avoid movements and exercises which can worsen the symptoms. Also, avoid bearing weight on the affected knee. This may be needed for a few days to a few weeks.
• Elevation of the affected knee using a pillow whilst taking rest will help reduce swelling, pain, and discomfort. You can try using a stool to rest the affected knee when sitting during the day.
• Ice application (recommended within 24 hrs of pain) or placing a bag of frozen peas wrapped in a towel (never place the cold substance directly on the skin) can alleviate pain to an extent. A cold compress reduces swelling and redness.  Apply for about 20 minutes every few hours during the day until the symptoms subside. 
• You can also try supporting the affected knee using compression bandages or sleeves (recommended to wear for a few weeks). This will help reduce the swelling as well as manage the pain better, especially when walking.
• Over-the-counter painkillers such as paracetamol or ibuprofen can be effective but should be taken only after meals. Other non-steroidal anti-inflammatory drugs (NSAIDs) are also available as creams and ointments (avoid if there is a break in the overlying skin). In case you are unsure if you can take them or suspect you might be allergic, consult a physician to avoid potential side effects.⁴
• Home remedies can provide temporary relief, however, it is important to inform your physician of persistent pain. If the physician rules out bursal infection, steroid injections can be injected into the affected knee. Steroid injections will help reduce the swelling and pain in the affected bursa. It can take a couple of days for the pain to be relieved. They may also refer you to the physiotherapist for specialized physical therapies and stretching exercises.

If you are an athlete, or sports professional, your physician may refer you to a sports specialist. Surgery could be considered as the last line of treatment, to remove the affected prepatellar bursa if the inflammation is persistent or in cases of infection that has not resolved despite antibiotics and aspiration. The surgical procedure is performed by orthopaedic surgeons.

Recovery

With prompt and proper treatment, most people with knee bursitis recover within a few weeks. If septic prepatellar bursitis is not promptly treated, it may lead to long standing knee pain and other problems.

Prevention

When the risk factors are identified, for instance professions, hobbies, or sports where prolonged kneeling or risk of knee injuries occur, preventative measures are advised to reduce the risk of developing knee bursitis.

These include:

• Use of knee pads
• Taking several breaks from kneeling to reduce tension in the knee.
• Weight loss if you are overweight and aim to maintain a healthy weight.²

Summary

Prepatellar bursitis is a common type of knee inflammation. It is a painful condition which is more commonly seen in professions which involve constant kneeling for prolonged periods of time. If the pain and swelling are not relieved by home remedies, it is advised to consult a physician who will perform physical examination of the affected area and give a proper diagnosis. Depending on the level of inflammation, there are several treatment options which includes administering steroid injections and surgical incision (in some cases of infected bursitis).