[C-reactive protein and transthyretin in early diagnosis of infection after open fractures of the lower limbs (a preliminary study)].
OBJECTIVE
The authors investigated the value of C-reactive protein (CRP) and transthyretin (TTR) in the early diagnosis of infection after open fractures of the lower limb in an open, prospective study.


METHODS
Eighty patients were treated with acute debridement and bone fixation. Follow-up included clinical, radiological, bacteriological and biological assessment: white cell blood count (WBC), erythrocyte sedimentation rate (ESR), CRP and TTR. Diagnosis of infection was based on macroscopic presence of pus.


RESULTS
Post-operative reference biological profiles were defined in 74 cases without infection. Reference profiles of WBC and ESR showed unreliable interindividual variations and could not be considered for the diagnosis of infection. Reference profiles of CRP and TTR showed a respective increase (for CRP) and decrease (for TTR) in the early post-operative course, with return to normal values after 12 days. In 6 infected patients, CRP concentrations were suddenly increased and TTR concentrations decreased at the time (3 cases) or even before (3 cases) clinical diagnosis of infection. These variations were mostly simultaneous. No unusual profile was found. The ratio of CRP/TTR concentrations experienced also a sudden increase in infected cases.


CONCLUSIONS
Because of not specifical and unreliable variations in the post-operative outcome of non infected patients, WBC and ESR cannot be considered for the early diagnosis of infection. CRP and TTR concentrations with a respective cut-off value of 100 mg/L and 120 mg/L were found efficient for the early diagnosis of infection, and preceded clinical diagnosis in three of them. A CRP/TTR ratio over 60 p. 100, 8 days or more after initial surgery was found to be very specific (93 p. 100) and sensitive (100 p. 100) for the diagnosis of infection.


CONCLUSIONS
Serial quantifications of CRP and TTR should be performed every four days during the follow-up of open fractures in order to early diagnose a post-operative infection. Comparison of both CRP and TTR could allow a higher accuracy, because of the possible lack of variation of one the two markers.
Jenny
J Y
JY
Centre de Traumatologie et d'Orthopédie, Illkirch.
Gaudias
J
J
Bourguignat
A
A
Férard
G
G
Kempf
I
I
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015415:Biomarkers; D002097:C-Reactive Protein / Q000032:analysis*; D005260:Female; D005592:Fracture Fixation; D005597:Fractures, Open / Q000150:complications* / Q000601:surgery; D006801:Humans; D007869:Leg Injuries; D008297:Male; D008875:Middle Aged; D011228:Prealbumin / Q000032:analysis*; D011446:Prospective Studies; D013530:Surgical Wound Infection / Q000175:diagnosis; D013997:Time Factors; D014946:Wound Infection / Q000175:diagnosis* / Q000209:etiology
D015415:Biomarkers; D011228:Prealbumin; D002097:C-Reactive Protein