Radiological signs of osteitis around extramedullary metal implants - A radiographic-microbiological correlative analysis in rabbit tibiae after local inoculation of Staphylococcus aureus

Radiographic changes in the early stages of osteomyelitis may be subtle and , especially after plate os teosynthesis, frequently missed. A previously d escribed experimental model of local bacterial infection was used in an att empt to determine the reliability of specific changes on conventional radio graphs for the diagnosis of osteitis after metal-plate implantation and sub sequent inoculation of Staphylococcus aureus in rabbit tibiae. Roentgeno-gr ams of the treated Limbs were evaluated, and seven radiographic parameters, to which numerical scores were assigned, were determined for each bone. Ou r results substantiate the conclusion that a radiographically verified peri osteal reaction is a constant and early skeletal feature of acute osteomyel itis:and has the strongest association to the microbiological results (P < 0.05), emphasising its high predictive value. Plate implantation does not n otably impede the diagnosis of osteomyelitis. An association between the am ount of inoculated bacteria and the extent of radiographic changes could be found. The results of this present study closely resemble those described in man and suggest that this model may be useful for future experimental in vestigations in determining a score judging the severity of osseous involve ment in local bacterial infection after plate osteosynthesis.