If the<unk>  is swollen, red and warm to the touch when compared to the other<unk> , inflammation due to rheumatoid arthritis or a crystalline arthritis, such as gout or pseudogout, or joint infection can be considered. Besides sending the joint fluid to a laboratory for analysis, white blood cell count, erythrocyte sedimentation rate, and perhaps the level of C-reactive protein or uric acid must also be monitored.  If blood tests reveal Lyme's disease antibodies forming, the condition may be attributed to it.
Knee pain/swelling laboratory findings
Bursitis laboratory findings
Osteoarthritis laboratory findings
Septic arthritis laboratory findings
Dislocated patella physical examination
Knee pain/swelling x ray
Osteomyelitis laboratory findings
Bursitis physical examination