Significance of epiphyseal cartilage enhancement defects in pediatric osteomyelitis identified by MRI with surgical correlation.

Background: Epiphyseal cartilage enhancement defects (ED) may occur in the setting of epiphyseal osteomyelitis (OM), and its significance is uncertain.
Objective: The aim of this study is to evaluate the incidence and clinical impact of epiphyseal cartilage ED in pediatric epiphyseal OM.
Materials and Methods: The 13 children involved in this retrospective review were younger than 6 years of age and diagnosed with OM. They underwent contrast-enhanced MRI and surgical exploration yielding 14 study epiphyses. Seventeen age-matched children without evidence of infection who underwent contrast-enhanced MRI in the same period yielded 28 control epiphyses. Images were reviewed for focal/global ED, correlated with cartilage abscesses and compared with surgical reports.
Results: Study and control ED were respectively present in 10/14 (71.4%-6 global, 4 focal) and 6/28 (21.4%-0 global, 6 focal), P=0.0017. An analysis of ED patterns between study and control patients showed significant difference for global (P=0.0006), but no difference for focal ED (P=0.71). For the six study epiphyses with global ED, epiphyseal abscesses were present in two (33.3%). For the four study epiphyses with focal ED, epiphyseal abscesses were present in two (50%). For the controls, no abnormalities were found on follow-up of epiphyses with focal ED.
Conclusion: ED are seen normally but more commonly in children with OM. ED should not be confused with epiphyseal abscesses.