Bursitis: Causes, Risk Factors, and Prevention

What causes bursitis?

Bursitis is primarily caused by repetitive motion, prolonged pressure, or direct trauma to a bursa, leading to inflammation of this fluid-filled sac that cushions joints and reduces friction between tissues.

Understanding Bursitis: A Brief Overview

To understand what causes bursitis, it's essential to first grasp what a bursa is and its physiological role. Bursae (plural of bursa) are small, thin, slippery sacs filled with synovial fluid, strategically located throughout the body, particularly near large joints and between bones, tendons, and muscles.

• Function of Bursae: Their primary function is to act as cushions, reducing friction and pressure points during movement. They allow tendons and muscles to glide smoothly over bony prominences, facilitating pain-free motion.
• What Happens in Bursitis: When a bursa becomes inflamed, it swells with excess fluid, leading to pain, tenderness, and restricted movement in the affected area. This inflammation is what defines bursitis.

Primary Causes of Bursitis

The inflammation of a bursa typically arises from mechanical stress or injury.

• Repetitive Motion and Overuse: This is the most common cause of bursitis. Engaging in activities that involve repeated movements of a specific joint or body part can lead to cumulative microtrauma to the bursa.
  • Mechanism: Each repetitive motion can cause friction or compression on the bursa. Over time, this constant irritation overwhelms the bursa's ability to recover, leading to inflammation and swelling.
  • Examples:
    • Shoulder: Repeated overhead lifting, throwing (e.g., baseball, painting, swimming).
    • Elbow: Repetitive gripping, swinging (e.g., tennis, golf, carpentry).
    • Knee: Repetitive kneeling (e.g., gardening, carpet laying).
    • Hip: Repetitive walking, running, cycling, or squatting.
• Direct Trauma or Injury: An acute impact or fall directly onto a bursa can cause immediate inflammation.
  • Mechanism: The direct force can damage the bursa's lining, causing fluid accumulation and an inflammatory response.
  • Examples: Falling directly onto the knee, elbow, or hip; a direct blow during sports.
• Prolonged Pressure: Sustained pressure on a bursa can also lead to inflammation, particularly in areas exposed to external compression.
  • Mechanism: Constant pressure restricts blood flow and irritates the bursa, leading to fluid buildup and inflammation.
  • Examples:
    • Prepatellar Bursitis ("Housemaid's Knee"): Resulting from prolonged kneeling.
    • Olecranon Bursitis ("Student's Elbow"): From leaning on elbows for extended periods.
    • Ischial Bursitis ("Weaver's Bottom"): From prolonged sitting on hard surfaces.

Contributing Factors and Risk Modulators

While repetitive motion, trauma, and pressure are primary causes, several other factors can increase the risk or directly lead to bursitis.

• Infection (Septic Bursitis): Bursae close to the skin surface are vulnerable to bacterial infection.
  • Mechanism: Bacteria can enter the bursa through cuts, scrapes, insect bites, or punctures in the skin overlying the bursa. This leads to a more severe inflammatory response, often accompanied by redness, warmth, fever, and significant pain.
  • Common Sites: Olecranon (elbow) and prepatellar (knee) bursae are most commonly affected due to their superficial location.
• Arthritic Conditions: Systemic inflammatory conditions can cause bursitis as a secondary manifestation.
  • Examples: Rheumatoid arthritis, gout, pseudogout, and psoriatic arthritis can cause inflammation in various tissues, including bursae, as part of their broader disease process.
• Poor Biomechanics and Posture: Imbalances in muscle strength, flexibility, or gait can alter normal joint mechanics, placing undue stress on bursae.
  • Mechanism: Incorrect movement patterns or postural habits can increase friction or compression on specific bursae, making them more susceptible to inflammation.
  • Examples: Tight IT band contributing to trochanteric bursitis; muscular imbalances around the shoulder leading to subacromial bursitis.
• Improper Exercise Technique: Incorrect form during physical activity can overload specific joints and their associated bursae.
  • Mechanism: Poor technique can concentrate stress in ways that natural biomechanics are not designed to handle, leading to localized irritation.
  • Examples: Overloading the shoulder joint during bench pressing or overhead presses with poor form; improper squatting mechanics irritating knee bursae.
• Age: The risk of bursitis generally increases with age.
  • Mechanism: Tendons and tissues around joints can become less elastic and more susceptible to injury over time. Degenerative changes in joints may also alter biomechanics.
• Certain Medical Conditions: Some health conditions can predispose individuals to bursitis.
  • Examples: Diabetes can increase susceptibility to infections, including septic bursitis. Thyroid disease can also be a contributing factor in some cases.

Common Locations for Bursitis and Their Typical Causes

Bursitis can occur in any bursa, but some locations are far more common due to their exposure to repetitive motion, pressure, or trauma.

• Shoulder (Subacromial/Subdeltoid Bursitis): Often caused by repetitive overhead activities (e.g., throwing, painting, swimming, lifting), rotator cuff impingement, or direct trauma.
• Elbow (Olecranon Bursitis): Commonly known as "student's elbow" or "baker's elbow," it results from prolonged leaning on the elbow, direct trauma, or repetitive flexion/extension.
• Hip (Trochanteric Bursitis): Affects the bursa on the outside of the hip. Causes include repetitive activities like running, cycling, or stair climbing; direct trauma; leg length discrepancy; or poor posture. Ischial bursitis (sits bone) is caused by prolonged sitting on hard surfaces.
• Knee (Prepatellar and Pes Anserine Bursitis):
  • Prepatellar Bursitis ("Housemaid's Knee"): Caused by prolonged or repetitive kneeling.
  • Pes Anserine Bursitis: Affects the inner knee, often due to tight hamstrings, obesity, knee arthritis, or overuse in activities like running.
• Heel (Retrocalcaneal and Achilles Bursitis):
  • Retrocalcaneal Bursitis: Located at the back of the heel, often irritated by rigid shoe backs or repetitive pressure.
  • Achilles Bursitis: Inflammation of the bursa between the Achilles tendon and the heel bone, often associated with tight Achilles tendons or overuse.

Prevention Strategies

While not all cases of bursitis are preventable, many can be avoided or mitigated through careful attention to activity, biomechanics, and ergonomics.

• Gradual Activity Progression: Increase the intensity and duration of activities slowly to allow tissues to adapt.
• Proper Technique: Learn and use correct form for sports, exercise, and occupational tasks to minimize undue stress on joints.
• Ergonomics: Modify workspaces and daily habits to reduce prolonged pressure or repetitive movements on vulnerable bursae.
• Strength and Flexibility: Maintain balanced strength and flexibility around major joints to support proper biomechanics and reduce strain.
• Protective Padding: Use knee pads, elbow pads, or other cushioning devices when engaging in activities that involve prolonged pressure or kneeling.

When to Seek Medical Attention

While many cases of bursitis resolve with rest and conservative management, it's important to seek medical advice if:

• Pain is severe or rapidly worsening.
• You develop a fever, chills, or general malaise.
• The affected area becomes significantly red, warm, or swollen.
• You cannot move the affected joint.
• Symptoms do not improve after a week of self-care.

Understanding the causes of bursitis empowers individuals to take proactive steps in prevention and seek appropriate care when symptoms arise.