hi, my son is 4 and for over a week now he has complained about pain behind his knees. one is usually worse than the other but it it often different knees. we have had hip X-ray and knee X-rays, we spent a night in paediatrics last week and he had full bloods and urine test. Urine test was nad and bloods were ok except wcc was 15 i think and ESR elevated to around 50 i think from what i can remember but could be wrong about the number but it was elevated...both X-rays were nad too...the doctors thought he may have had an affective arthritis or something and as he had a fever the day i brought him in too and nil the whole time we were in hospital or prior...no previous illness except a possible sore throat...its been 3 days since we came home and he still has to have neuronen now and again for the pain and today he had severe pain and temp of 37.9 he had no redness or swelling around the knee, we have not been overseas, he had a good rom when we were in hospital and drs were examining his legs...he is normally a fit and healthy kid...just not sure where to go from here...