I had knee weakness for a 1 'n half month, no pain, sometimes popping, some swelling below the patella. recently gotten slightly worse, any advice?

Patellar bursitis: Sounds like patellar or prepatellar bursitis. Ice and some rest to knee may help. Also Advil (ibuprofen) or alleve daily may benefit. If not better or worsening may need to see ortho, possible cortisone injection.

Patellar imbalance: Likely the Is is due to some maltracking of the knee cap and can be corrected with therapy. Given the limited info I would suggest an eval with your doctor and possibly a therapy prescription.

Patellar tendonitis: Consider patellar tendonitis, jumper's knee, PFS, sprain, meniscal tear, loose body, synovitis. Try rest, ice, open patellar sleeve. Limit squat and full arc exercises. insider purified omega, NSAIDs, modalities/laser therapy. Check with orthopedic surgeon or sports med doc if not better with above.

Get examined: Swelling and pain in that area needs to be checked for tendonitis, which should respond to the Ibuprofen (at prescription doses, supervised.) Stairs and kicking sports can aggravate this. Alternative problems inside the knee and medical conditions must be considered. See a musculoskeletal doctor, or start with your primary physician for a referral. Good luck.

See below: If you're not have any history Of trauma fever weight-loss chills , night sweats other joint problems and others symptoms such as flulike symptoms a trial of a supervised physical therapy regimen who specializes in orthopedic musculoskeletal skeletal injuries for a few weeks to a month with icing after your exercise and short courses of anti-inflammatory medication with food if not medically contraindicated. If you don't get better and you weeks to a month I would go see an orthopedic surgeongood luck thank you