The value of successive Infecton scans in assessing the presence of chronic bone and joint infection and in predicting its evolution after treatment and after a prolonged follow-up.

OBJECTIVE

Our objective was to monitor the evolution of bone and/or joint infections with the aid of successive radiolabelled ciprofloxacin (Infecton) scans during antimicrobial treatment and to compare the results of an Infecton scan at the end of therapy with the respective results of clinical evaluation, erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) in predicting resolution or recurrence of infection after a long period of posttreatment follow-up.

METHODS

Thirty-three patients with documented bone and/or joint infection were subjected to successive Infecton scans on two or three visits. Infecton scans were evaluated visually and scored accordingly. Clinical evaluation was scored by the referring clinicians. ESR and CRP values were evaluated independently. A minimum of 2-year free-of-infection follow-up after discontinuation of the antibiotic treatment served as a measure of successful antimicrobial therapy and nonrecurrence of infection. Statistics included survival analysis (Cox regression).

RESULTS

During follow-up, five patients in the study presented with recurrence, and three died as a result of an irrelevant cause. The remaining patients were followed up for a median of 108 months (range 97-132 months) without any signs of recurrence of infection. Recurrence of infection was 4.2 times more likely to occur in patients with positive Infecton scans [hazard ratio (HR): 4.2, confidence intervals 95%: 1.39-12.67, P=0.011]. Infecton had the highest sensitivity (83.3%), accuracy (69.69%) and negative predictive value (94.74%), whereas CRP had the highest specificity (76.92%).

CONCLUSION

Infecton scintigraphy proved to be more sensitive and accurate and had a higher negative predictive value compared with clinical evaluation, ESR and CRP in predicting infection resolution or recurrence in patients with chronic bone and joint infections.