Why Is Only One Knee Swollen?
Noticing swelling in just one knee while the other remains normal can feel concerning. When both knees swell, it often signals a whole-body (systemic) issue like arthritis. However, swelling limited to one knee usually points to a localized problem. Knowing what might cause one swollen knee can help you figure out whether it’s a minor concern or something needing medical care.
1. Injury or Trauma
The most common reason for one swollen knee is injury. Sometimes the cause is obvious, like a fall or sports mishap, but other times, repeated stress or minor strains can lead to swelling without a clear incident. Potential injuries include:
Ligament sprains or tears (like ACL or MCL injuries)
Meniscus tears
Dislocation of the kneecap (patellar dislocation)
Bone bruises or fractures
Typically, swelling appears quickly and may come with pain, stiffness, or a feeling of instability.
2. Bursitis
