painful gait on the involved side which causes a limp.

a a knock-kneed or bowlegged condition. Most often there is a loss of complete extension (flexion contracture), and the inability to fully bend the knee.

Very often there is swelling.

Frequently bone spurs may be felt on the inside or outside of the joint.

When the knee is moved through a range of motion, crepitus is present.

There is usually tenderness around the inside and outside portions of the joint line.

It is important to distinguish knee arthritis from hip arthritis or disc degeneration in the lumbar spine, since the symptoms are similar.

Diagnostic test and imaging
Usually, plain X-rays will show the presence of arthritis and any abnormalities in the alignment of the lower leg and changes in the mechanical axis. MRI scanning is usually not necessary to diagnose knee arthritis. There are four classic features of knee arthritis:

• Joint space narrowing
  
• Flattening of the femoral condyle (the end of the femur)
  
• Subchondral sclerosis (reactive bone thickening)
  
• Peripheral bone spur formation