The evaluation of knee pain begins with a history and physical exam.

Physical findings may include:

• Bruising
• Decreased range of motion
• Knee swelling
• Deformed knee
• Inability to stand
• Numbness in the leg below the knee
• Tenderness
• Weakness in the leg below the knee

Tests are necessary to exclude a serious cause of knee pain.

Tests may include:

• Serum uric acid level
• Lyme disease assay
• HLA B27 assay
• Blood anti-DNAase B
• Blood anti-streptozyme
• Blood ASO titers
• Erythrocyte sedimentation rate
• Complete blood count

Other tests may include:

• Knee x-ray
• Extremity ultrasound
• Arthroscopy
• Arthrocentesis
• Bone scan
• MRI scan of the knee