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

Epiphyseal cartilage enhancement defects (ED) may occur in the setting of epiphyseal osteomyelitis (OM), and its significance is uncertain. The aim of this study is to evaluate the incidence and clinical impact of epiphyseal cartilage ED in pediatric epiphyseal OM. 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. 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. ED are seen normally but more commonly in children with OM. ED should not be confused with epiphyseal abscesses. (orig.)