Pain in the front portion of the knee can be caused by bursitis (inflammation of the lining of the joint, possible due to injury), arthritis, or injury
to the patella cartilage (front portion of the knee
). Pain on either sides of the knee
is usually related to meniscal tears, injuries to the collateral ligaments, and even to arthritis. Pain in the back of the knee can be caused by arthritis or Bakers cysts (cystic accumulation of synovial fluid, also causes a swelling).