Musculoskeletal examination and the limping child — formative SAQs

SAQ 1 (10)

A five-year-old boy is brought to the emergency department with a one-day history of a limp and refusing to walk properly. He had a viral upper respiratory infection last week. His temperature is 39.2 degrees Celsius, he holds his right hip flexed and abducted and resists any movement, and he will not bear weight on the right leg. ^{[4] [8]}

a) State the four Kocher predictors for differentiating septic arthritis from transient synovitis of the hip, and give the predicted probability of septic arthritis when all four are present. (4 marks) ^[4]

b) Name the additional predictor identified in the Caird prospective study, state its threshold, and explain why it strengthens the bedside prediction. (2 marks) ^[6]

c) Outline the immediate management of this child, naming the investigation that is both diagnostic and therapeutic and the team that must be involved. (2 marks) ^[7]

d) The parents ask whether this is just a viral limp that will settle. Explain in plain language why this child cannot be managed conservatively and what the risk of delay is. (2 marks) ^[4]