condition explainer
Knee Bursitis: Symptoms, Causes & Treatment
This article is for educational purposes only. It is not medical advice. If you’re experiencing knee pain, consult a healthcare professional.
What is knee bursitis?
A bursa is a small fluid-filled sac that cushions the gliding surfaces between bone, tendon, and skin. The knee has four main bursae that can become inflamed: the prepatellar (in front of the kneecap), the infrapatellar (just below the kneecap), the pes anserine (on the inner side of the knee, about 2-3 inches below the joint), and the suprapatellar (above the kneecap, communicating with the joint itself).
Bursitis is inflammation of one of these sacs. The bursa swells with extra fluid, the lining thickens, and the area becomes painful — particularly when pressure is applied or the joint is moved through certain ranges.
Symptoms — what to look for
The pattern varies depending on which bursa is inflamed, but common features include:
- Localised swelling — a soft, often visible lump over the affected bursa, not deep inside the joint
- Pain on direct pressure — kneeling, leaning on the knee, or wearing tight clothing aggravates it
- Warmth and redness over the affected area
- Stiffness with prolonged sitting or after activity
- Limited range of motion when the swelling is large enough to mechanically restrict bending
Prepatellar bursitis (the most common form) produces a visible “lump on top of the kneecap” appearance. Pes anserine bursitis typically causes inner-knee pain ~2-3 inches below the joint line, often worse climbing stairs or rising from a chair.
Causes & risk factors
Knee bursitis usually develops from one of three mechanisms:
- Repetitive pressure or kneeling — flooring installers, gardeners, plumbers, roofers, and tilers are over-represented in prepatellar bursitis cases (the historical name “housemaid’s knee” reflects this).
- Direct trauma — a fall or blow to the knee can rupture small blood vessels in the bursa, causing acute swelling.
- Inflammatory or infectious causes — gout, rheumatoid arthritis, and bacterial infection (septic bursitis) can all cause bursa inflammation. Septic bursitis is a medical emergency.
Risk factors include occupations requiring kneeling, obesity (loading the pes anserine bursa), tight hamstrings, and underlying inflammatory conditions.
When you must see a doctor urgently
Most bursitis is uncomplicated. Septic bursitis, however, requires immediate medical attention. Warning signs:
- Rapidly increasing redness, warmth, and tenderness
- Fever or feeling generally unwell
- A break in the skin near the bursa before symptoms began
- Pain disproportionate to the swelling
If any of these are present, see a doctor that day — septic bursitis is treated with antibiotics and sometimes drainage, and untreated infection can spread.
Diagnosis
A clinician typically diagnoses bursitis through physical examination — palpating the swelling, testing range of motion, and assessing for warmth and tenderness. Imaging is usually not needed for uncomplicated cases, but ultrasound or MRI may be used to confirm the bursa is involved (rather than the joint itself) or to rule out a complication. If infection is suspected, fluid is aspirated from the bursa and analysed.
Treatment — conservative options first
Most knee bursitis resolves with conservative management over 2-6 weeks.
1. Activity modification. Remove the trigger. For occupational kneelers, use thick kneeling pads and limit time on the knee. For athletes, modify training volume temporarily.
2. Ice and elevation. Ice the area for 15-20 minutes several times a day during the acute phase to reduce swelling. Elevate the leg above heart level when resting.
3. Compression. A snug knee sleeve provides gentle, even compression around the bursa, helping reduce swelling and providing proprioceptive feedback. Compression sleeves with a patellar cutout are particularly useful for prepatellar bursitis. See our compression-sleeve recommendations.
4. Topical anti-inflammatories. Topical NSAIDs (such as diclofenac gel) and counter-irritants (Biofreeze, Tiger Balm) can reduce surface inflammation and pain. They have a more favourable side-effect profile than oral NSAIDs for localised conditions. See pain-relief topical options.
5. Oral medications. Over-the-counter NSAIDs (ibuprofen, naproxen) help when used as directed, but they have important contraindications — discuss with a pharmacist or doctor, particularly if you have GI, cardiovascular, or renal history.
6. Physical therapy. For pes anserine bursitis especially, strengthening the hip abductors and quadriceps and addressing tight hamstrings often resolves recurring cases.
Treatment — medical options
When conservative care doesn’t resolve the bursitis within 4-6 weeks, or when symptoms are severe, options escalate:
- Aspiration — drawing fluid out of the bursa with a needle for diagnostic and symptomatic relief
- Corticosteroid injection — directly into the bursa to reduce inflammation. Used judiciously because repeated injections can weaken local tissue.
- Antibiotics — for septic bursitis, oral or intravenous depending on severity
- Surgical bursectomy — rarely needed, reserved for chronic recurrent cases that fail all other treatment
Prevention
If you’ve had bursitis before, you’re prone to it again. Preventive measures:
- Kneeling protection — use proper kneepads for any occupation or activity that involves time on the knee. See knee support options.
- Gradual training progression — avoid sudden volume increases in running, jumping, or kneeling activity
- Address contributors — manage body weight, treat underlying gout or arthritis, strengthen hip and quadriceps muscles
Recommended products for this condition
Affiliate disclosure: As an Amazon Associate, Knee Joint Relief earns from qualifying purchases. The picks below are products we’d recommend based on the conditions and treatment options discussed in this article. They are not medical advice — please consult a healthcare professional for guidance specific to your situation.
Powerlix Compression Knee Sleeve — Gentle even compression to manage bursa swelling
Voltaren Arthritis Pain Gel (1.7oz) — Topical NSAID for localised bursa inflammation
DonJoy Iceman Classic3 Cold Therapy Unit — Continuous cold therapy for substantial swelling
Related reading
- Bursitis & Baker’s Cyst category
- Knee braces & supports
- Pain relief topicals
- Methodology — how we research and review
Sources
This article draws on:
- American Academy of Orthopaedic Surgeons (AAOS) — Knee Bursitis
- Arthritis Foundation — Bursitis
- Mayo Clinic — Knee Bursitis
- Cleveland Clinic Health Essentials — Bursitis
- PubMed: Aaron DL et al. “Four common types of bursitis.” J Am Acad Orthop Surg. 2011
For specific citations, see our methodology.