If the swelling comes on suddenly and is very painful, the cause may be gout—a type of arthritis caused by uric acid crystals. Pseudogout, which involves calcium crystals, can cause similar symptoms. These conditions often affect only one joint at a time and may return periodically.
5. Osteoarthritis (Localized)
Though osteoarthritis typically affects both knees over time, it can start in just one knee, especially if that knee has experienced past injuries or bears more weight. Swelling may be mild to moderate and worsen with activity.
6. Baker’s Cyst
A Baker’s cyst is a fluid-filled swelling that develops at the back of the knee. It’s often caused by conditions like arthritis or a cartilage tear and may make one knee feel tight or swollen—especially when bending or straightening the leg.
7. Bl00d Clot or Circulation Issue
Though rare, a blood clot (deep vein thrombosis) in the leg can cause swelling in the knee area, especially if combined with calf swelling, warmth, or pain. It’s a medical emergency and needs immediate attention.
When to See a Doctor
You should seek medical help if:
- The swelling is sudden, severe, or accompanied by fever
- The knee is hot, red, or painful to touch
- You can’t walk or bend the knee
- Swelling lasts more than a few days without improvement
Final Thoughts
One swollen knee isn’t always a reason to panic, but it’s definitely something to pay attention to. From minor injuries to more serious joint diseases or infections, there are many possible reasons. Getting a proper diagnosis is the first step to effective treatment and long-term knee health.
