Knee Bursitis: A Comprehensive Guide

Overview

Knee bursitis is a painful condition that occurs when one or more of the bursae (small, fluid-filled sacs) in or around your knee joint become inflamed. Bursae act as cushions between bones, tendons, and muscles, reducing friction during movement. When they become irritated or infected, they swell, causing pain and limited mobility.

Who Does It Affect?

Knee bursitis can affect anyone, but it is most common in:

• People who engage in repetitive knee movements (e.g., gardeners, carpet layers, athletes).
• Individuals who frequently kneel for work or hobbies (e.g., plumbers, roofers, religious practices).
• Athletes, particularly runners, basketball players, and cyclists.
• Middle-aged and older adults, as bursae tend to degenerate with age.
• People with conditions like arthritis, gout, or diabetes, which increase inflammation risk.

Prevalence

Bursitis accounts for about 0.4% of all primary care visits in the U.S. annually, with knee bursitis being one of the most common types (NIH). The prepatellar bursa (located over the kneecap) is most frequently affected, especially in professions requiring kneeling.

Symptoms

Symptoms of knee bursitis vary depending on which bursa is affected and the severity of inflammation. Common signs include:

Primary Symptoms

• Pain: Often worsens with movement, kneeling, or pressure on the knee. The pain may start as a dull ache and progress to sharp or throbbing discomfort.
• Swelling: Visible or palpable swelling around the knee. In prepetellar bursitis ("housemaid's knee"), swelling appears as a soft, fluid-filled lump over the kneecap.
• Redness and warmth: The skin over the affected bursa may appear red or feel warm to the touch, especially if infected (septic bursitis).
• Stiffness: Difficulty bending or straightening the knee, particularly after periods of inactivity (e.g., morning stiffness).
• Tenderness: The area around the bursa is sensitive to touch.

Additional Symptoms (Less Common)

• Fever or chills: If the bursitis is caused by an infection (septic bursitis), systemic symptoms like fever may occur.
• Bruising: In cases of traumatic bursitis (e.g., after a fall or direct blow to the knee).
• Limited range of motion: Severe swelling may restrict knee movement.

Symptoms may develop gradually (chronic bursitis) or appear suddenly (acute bursitis), often after an injury or overuse.

Causes and Risk Factors

Common Causes

• Repetitive motion: Frequent kneeling, squatting, or crawling irritates the bursa. Examples include:
  • Occupational activities (e.g., flooring installation, plumbing, gardening).
  • Sports (e.g., volleyball, wrestling, football).
• Direct trauma: A hard blow to the knee (e.g., falling onto the kneecap) can cause acute bursitis.
• Prolonged pressure: Kneeling for extended periods on hard surfaces (e.g., during prayer or cleaning).
• Infection: Bacteria can enter the bursa through a cut, scrape, or insect bite, leading to septic bursitis. Staphylococcus aureus is the most common cause (NIH).
• Underlying conditions:
  • Arthritis (e.g., rheumatoid arthritis, osteoarthritis, gout).
  • Diabetes or other metabolic disorders.
  • Autoimmune diseases (e.g., lupus).

Risk Factors

Factors that increase your risk of developing knee bursitis include:

• Age (bursae degenerate over time).
• Obesity (increases pressure on the knees).
• Poor knee padding (e.g., not using kneepads during work or sports).
• Previous knee injuries or surgeries.
• Weak thigh muscles (quadriceps), which can alter knee mechanics.
• Improper technique during physical activities (e.g., poor form while lifting or running).

Diagnosis

Diagnosing knee bursitis typically involves a combination of medical history, physical examination, and imaging or lab tests.

Medical History and Physical Exam

Your doctor will ask about:

• Your symptoms (e.g., pain location, duration, triggers).
• Recent injuries or activities involving the knee.
• Occupation, hobbies, and exercise routines.
• Medical history (e.g., arthritis, diabetes, previous bursitis).

During the exam, the doctor will:

• Inspect the knee for swelling, redness, or deformities.
• Palpate (feel) the knee to identify tender areas or fluid-filled sacs.
• Assess range of motion and strength.
• Check for signs of infection (e.g., fever, warmth, redness).

Diagnostic Tests

If the diagnosis is unclear or septic bursitis is suspected, your doctor may order:

• Imaging tests:
  • X-rays: To rule out fractures or arthritis (though bursitis itself doesn’t show on X-rays).
  • Ultrasound: To confirm fluid in the bursa and guide drainage if needed.
  • MRI: Rarely used, but helpful for complex cases or to rule out other conditions (e.g., meniscus tears).
• Lab tests:
  • Joint aspiration (fluid analysis): A needle is used to withdraw fluid from the bursa. The fluid is tested for:
    • Infection (bacteria, white blood cell count).
    • Crystals (e.g., gout or pseudogout).
    • Blood (indicating trauma).
  • Blood tests: To check for underlying conditions like gout, rheumatoid arthritis, or infection (e.g., elevated CRP or ESR levels).

Treatment Options

Treatment for knee bursitis depends on the cause (e.g., traumatic, infectious, or inflammatory) and severity. Most cases improve with conservative measures, but severe or infected bursitis may require medical intervention.

Home Remedies and Lifestyle Changes

• Rest: Avoid activities that worsen symptoms (e.g., kneeling, squatting). Use crutches if walking is painful.
• Ice: Apply ice packs for 15–20 minutes, 3–4 times daily, to reduce swelling. Always use a towel to protect your skin.
• Compression: Use an elastic bandage or knee sleeve to limit swelling, but avoid wrapping too tightly.
• Elevation: Prop your knee on pillows when sitting or lying down to reduce fluid buildup.
• Kneepads: Wear cushioned kneepads during activities that put pressure on your knees.
• Activity modification: Switch to low-impact exercises (e.g., swimming, cycling) until symptoms improve.

Medications

• Over-the-counter (OTC) pain relievers:
  • NSAIDs (e.g., ibuprofen, naproxen) to reduce pain and inflammation.
  • Acetaminophen (e.g., Tylenol) for pain relief if NSAIDs are contraindicated.
• Topical treatments:
  • NSAID creams or gels (e.g., diclofenac).
  • Lidocaine patches for localized pain relief.
• Corticosteroid injections: For persistent inflammation, a doctor may inject cortisol (e.g., cortisone) into the bursa to reduce swelling. Note: Not used for infected bursitis.
• Antibiotics: Required for septic bursitis. Oral antibiotics (e.g., dicloxacillin, cephalexin) are typically prescribed for 7–14 days. Severe infections may need IV antibiotics.

Medical Procedures

• Aspiration (drainage): A doctor uses a needle to drain excess fluid from the bursa, often combined with a corticosteroid injection. This provides immediate relief and helps confirm a diagnosis if infection is suspected.
• Physical therapy: A therapist can teach exercises to strengthen the quadriceps and hamstrings, improve flexibility, and correct movement patterns to prevent recurrence.
• Surgery: Rarely needed, but may be considered for:
  • Chronic bursitis that doesn’t respond to other treatments.
  • Recurrent septic bursitis.
  • Bursa removal (bursectomy) in severe cases.

Alternative Therapies

While not a substitute for medical treatment, some people find relief with:

• Acupuncture: May help reduce pain and inflammation (Mayo Clinic).
• Massage therapy: Gentle massage can improve circulation and reduce muscle tension around the knee.
• Supplements: Omega-3 fatty acids or turmeric may have anti-inflammatory effects (consult your doctor before trying supplements).

Living with Knee Bursitis

If you have chronic or recurrent knee bursitis, these strategies can help you manage symptoms and maintain mobility:

Daily Management Tips

• Protect your knees:
  • Use kneepads during activities that involve kneeling (e.g., gardening, cleaning, construction).
  • Avoid kneeling on hard surfaces. Use a cushioned mat or stool.
• Modify your workspace:
  • Adjust your workstation to minimize kneeling or squatting.
  • Use ergonomic tools (e.g., long-handled grippers to avoid bending).
• Exercise smartly:
  • Warm up before physical activity with dynamic stretches (e.g., leg swings, lunges).
  • Strengthen your quadriceps, hamstrings, and hip muscles to support the knee. Try:
    • Straight leg raises.
    • Wall sits.
    • Clamshells (for hip strength).
  • Avoid high-impact activities (e.g., jumping, deep squats) until symptoms resolve.
• Manage weight: Excess weight puts additional stress on your knees. A balanced diet and low-impact exercise (e.g., swimming, cycling) can help.
• Use assistive devices:
  • A cane or crutches can offload pressure from the affected knee.
  • A knee brace or sleeve may provide support and compression.
• Apply heat: After the initial swelling subsides, heat (e.g., warm towel, heating pad) can relax muscles and improve circulation.

When to Adjust Activities

Listen to your body and scale back if you experience:

• Increased pain during or after an activity.
• Swelling that worsens or doesn’t improve with rest.
• Redness, warmth, or fever (signs of infection).

Prevention

While not all cases of knee bursitis can be prevented, these steps can significantly reduce your risk:

Protective Measures

• Use kneepads: Wear cushioned kneepads during work, sports, or hobbies that involve kneeling (e.g., gardening, flooring, volleyball).
• Take breaks: Avoid prolonged kneeling or squatting. Stand up, stretch, and walk around every 20–30 minutes.
• Practice proper technique:
  • Lift with your legs, not your back, to avoid knee strain.
  • Use proper form during exercises (e.g., keep knees aligned with toes during squats).
• Strengthen and stretch:
  • Incorporate knee-strengthening exercises (e.g., leg presses, step-ups) into your routine.
  • Stretch your quadriceps, hamstrings, and calves daily to maintain flexibility.

Lifestyle Tips

• Maintain a healthy weight: Excess weight increases pressure on your knees. Aim for a BMI between 18.5 and 24.9.
• Stay active: Regular low-impact exercise (e.g., walking, swimming) keeps joints healthy and reduces stiffness.
• Wear supportive shoes: Choose shoes with good arch support and cushioning to reduce knee stress.
• Gradually increase activity: Avoid sudden increases in exercise intensity or duration to prevent overuse injuries.
• Treat underlying conditions: Manage arthritis, diabetes, or gout with your doctor’s guidance to reduce inflammation risk.

Complications

If left untreated, knee bursitis can lead to:

• Chronic pain and swelling: Persistent inflammation can cause long-term discomfort and limit mobility.
• Recurrent bursitis: Once a bursa is irritated, it may become inflamed more easily in the future.
• Septic arthritis: Untreated septic bursitis can spread infection to the knee joint, causing severe damage (CDC).
• Bursa thickening or scar tissue: Chronic inflammation may cause the bursa to thicken, leading to persistent swelling or stiffness.
• Muscle atrophy: Avoiding knee movement due to pain can weaken the quadriceps and other supporting muscles.
• Cellulitis: Skin infection around the knee, characterized by redness, warmth, and spreading swelling.

Early treatment and preventive measures can help avoid these complications. If symptoms persist beyond 1–2 weeks or worsen, seek medical attention.

When to Seek Emergency Care

Key Takeaways

• Knee bursitis is inflammation of the fluid-filled sacs (bursae) around the knee, often caused by overuse, trauma, or infection.
• Symptoms include pain, swelling, redness, and stiffness. Septic bursitis may cause fever and chills.
• Treatment typically involves rest, ice, compression, elevation (RICE), NSAIDs, and protective measures like kneepads.
• Septic bursitis requires antibiotics and possibly drainage. Chronic cases may need corticosteroid injections or physical therapy.
• Prevent recurrence by avoiding prolonged kneeling, strengthening knee muscles, and maintaining a healthy weight.
• Seek emergency care for signs of infection, severe pain, or deformity.

Reputable Sources for Further Reading

• Mayo Clinic: Bursitis
• Arthritis Foundation: Bursitis
• American Academy of Orthopaedic Surgeons: Bursitis
• NIH: Septic Bursitis
• Cleveland Clinic: Bursitis