Radiologically, earliest sign of osteomyelitis is -

Osteomyelitis is the infection of bone by microorganisms.It can be acute or chronic. Acute osteomyelitis: This can be primary (haematogenous)or secondary(following open fracture or bone opeaion). Staphylococcus aureus is the commonest causative organism. C/f: Child presents with an acute onset of pain and swelling at end of a bone,associated with systemic features of infection like fever. Investigations: Blood- polymorphonuclear leucocytosis and an elevated ESR. X-rays - The earliest sign to appear in X ray is a periosteal new bone deposition at metaphysis.This is called periosteal reaction.It takes about 7-10 days to appear. Bone scan- bone scan using Tc 99 may show increased uptake by bone in the metaphysis. REF:Essential Ohopaedics.Maheswari &Mhaskar.Edition 9.Pg no:169