Knee Bursitis: Why the Front of the Knee Swells. Knee bursitis explained: why a soft lump forms on the front of the knee, red flags for infection, self-care that works, and how treatments compare.
Knee bursitis is irritation of a small fluid-filled sac around the knee, most often the prepatellar bursa over the kneecap. It causes a soft, squashy swelling, pain when kneeling, and tenderness. Most cases settle within a few weeks with reduced kneeling, ice, compression and short-term anti-inflammatory care. Warmth, spreading redness or fever may mean infection and need prompt medical review. Persistent swelling linked to an underlying joint problem may need further assessment.
A soft, squashy lump on the front of the knee that appeared after a weekend of gardening or tiling is a classic sign of knee bursitis. The swelling can look alarming, but in most cases it is a simple irritation that settles with sensible care.
This guide explains what knee bursitis is, why it happens, when it needs urgent attention, and how the treatment options compare.
Bursitis affects a cushion outside the joint, not necessarily the cartilage inside it. This distinction matters because a visible lump over the kneecap may need pressure protection rather than treatment aimed at arthritis. The location of swelling helps a clinician identify which bursa is involved.
A bursa is a thin sac of fluid that lets skin and tendons glide over bone. The knee has several, and any of them can become irritated:
A physical examination is often enough to identify a typical case. Ultrasound or fluid testing may be considered when the diagnosis is uncertain, the swelling is unusual, or infection or gout is suspected.
The swollen area often feels soft because fluid collects close to the skin. Some people have a large lump with little pain, while others find even light kneeling uncomfortable. The amount of swelling alone does not show whether the bursa is infected.
Pain deep inside the knee, locking, or a whole-knee swelling may point to a different problem. Mention these symptoms during an assessment rather than assuming every swollen knee is bursitis.
Repeated pressure can irritate the bursa even without a major injury. A change in work, exercise or household tasks may explain why symptoms suddenly start. Repeatedly returning to the same pressure before the swelling settles can keep the irritation going.
A scrape or puncture near the swollen area changes the concern because bacteria can enter through damaged skin. People with diabetes or reduced immunity should have a lower threshold for medical review when redness or warmth develops.
A red, hot bursa needs assessment rather than home treatment alone. Fever can be absent even with infection, so increasing tenderness, spreading redness or drainage through the skin should not be ignored.
Seek prompt medical review if any of these appear:
Infected (septic) bursitis usually needs antibiotics and sometimes drainage.
Do not try to puncture or drain the lump at home. If a clinician suspects infection, testing the fluid can help guide treatment; severe pain, feeling very unwell or an inability to bear weight warrants urgent care.
The most useful change is removing direct pressure while keeping comfortable everyday movement. Complete bed rest is usually unnecessary for uncomplicated bursitis, but repeated kneeling can undo progress. A sleeve should feel supportive, not tight enough to cause tingling or skin colour changes.
Anti-inflammatory medicines are not suitable for everyone, particularly with kidney disease, stomach ulcers, blood thinners or pregnancy. Ask a pharmacist or clinician about safe pain relief, and seek review sooner if symptoms worsen rather than waiting several weeks.
Treatment depends on whether the swelling is caused by pressure, infection or another condition. Most uncomplicated cases start with protection and symptom control. A large swelling does not automatically need draining, because aspiration can introduce infection and the fluid may return.
| Option | What it does | Best suited to | Limits | |---|---|---|---| | Rest and padding | Removes pressure on the bursa | Most new cases | Swelling returns if kneeling resumes | | Physiotherapy | Restores motion and strength | Stiffness after swelling settles | Does not drain fluid | | Medication | Reduces pain and inflammation | Short-term flare control | Not suitable for everyone | | Aspiration | Drains fluid with a needle | Large or uncertain swellings | Fluid can reaccumulate | | Steroid injection | Calms non-infected inflammation | Stubborn non-infected cases | Infection must be ruled out first | | Cell-based therapy | Investigational, not established for this condition | Research discussion only | Benefit and long-term safety uncertain | | Surgery (bursectomy) | Removes the bursa | Repeated or chronic cases | Recovery time, wound risk |
Steroid injections into a superficial knee bursa are not routine and require careful consideration of infection and skin risks. Surgery is generally reserved for persistent, recurrent problems after less invasive care has failed.
There is no established evidence that MSC treatment resolves a swollen knee bursa. Research involving knee osteoarthritis should not be presented as proof of benefit for bursitis, even when both conditions occur in the same person.
Simple knee bursitis rarely needs advanced treatment. When front-of-knee swelling keeps returning alongside cartilage wear or arthritis, regenerative options such as cellular therapy are being studied as supportive care for the joint environment. Mesenchymal cells (MSCs) release signalling molecules that may help modulate inflammation. The evidence base is still developing, responses vary, and it is considered only after a full assessment, never as a first step.
An assessment should separate the bursal problem from any underlying joint disease. Experimental options need a clear explanation of uncertainty, risks, costs and alternatives; infection must be treated first, not masked by an elective procedure.
If swelling has not settled after three to four weeks of protection and ice, a physician review can confirm the diagnosis. For related symptoms, see knee pain when bending and knee pain when squatting. The joint pain support program page explains how evaluation works.
Knee bursitis causes soft swelling over or below the kneecap, usually from repeated kneeling or a direct knock, and it is not arthritis. Kneeling pads, rest, wrapped ice and anti-inflammatory gel help most cases settle. Redness, warmth or fever may signal infection and need same-day assessment.
This article is for general informational and educational purposes only and is not a substitute for personalized medical advice. Always consult a qualified healthcare professional before considering stem cell therapy.