A 3 year old boy presents to the Emergency Department with a limp. He has been reluctant to weight bear on his right leg during the day and has a temperature of 37.9°C. Hip examination is painful. What clinical or laboratory tests could help discriminate between septic arthritis and transient synovitis?

Of course, you could just ring up orthopaedics and ask them to take him to theatre and wash out the hip – but you may not win many friends that way. How do you decide there is enough ‘clinical suspicion’ to make the call?

Well, you’re fortunate to have a team of orthopaedic surgeon and paediatrician have answered this question for you. [EDIT – Jan 2009]

If you can’t wait for their answer, you might want to post your own here though … [EDIT – Jan 2009] Or now you can read their thoughts here

(Image from the files of the Royal College of Surgeons, Edinburgh)