<prompt> An adolescent child complains of night pain in the knee. It could be due to -Juvenile rheumatoid ahritisIdiopathic growth painOsteosarcomaPagets disease  <response>: Ans. is a i.e., Juvenile rheumatoid ahritis Causes of knee pain in adolescence ..Time of the knee pain helps in the diagnosis of the disorders : - I. Night pain indicates i Inflammatory disorder ---Juvenile rheumatoid ahritis. ii Bursitis, synovitis iii Tumor Osteosarcoma Pain at the end of the day and after activity indicates i Mechanical pain due to injury Continuous pain present day and night indicates i Infection --- Osteomyelitis, Septic ahritis ii Idiopathic adolescent anterior knee pain syndrome Chondromalacia patella. 