Clinical outcome of edema-like bone marrow abnormalities of the foot

PURPOSE: To evaluate the clinical outcome of edema-like bone marrow abnormal- ities seen on magnetic resonance (MR) images of the foot when their cause is unknown. MATERIALS AND METHODS: The clinical outcome of 31 patients (15 female patients, 16 male patients; mean age, 51; range, 10-79 years) with edema-like bone marrow abnormalities on MR images of the foot was determined. The relevance of three different edema patterns was compared: (a) exclusively ill-defined edema-like zones, (b) edema-like zones plus well-defined necrosis-like zones, and (c) edema-like zones plus linear structures indicating possible fractures. The different edema pat- terns were compared with persistence of pain. RESULTS: Fifty-four percent of all patients had pain persisting after 1 year, as calculated with the Kaplan-Meier method. The duration of pain in the various subgroups varied significantly (P = .049, log-rank test). The subgroup of patients with a well-defined necrosis-like zone had substantially longer-lasting pain than those with edema-like abnormalities only (n = 16) (P = .065). Only one of seven patients with a well-defined necrosis-like zone (n = 7) was pain free after 1 year. Conversely, patients with possible stress fracture (n = 8) had shorter pain compared with those with edema-like abnormalities only (P = .036); six of eight patients were pain free after 1 year. CONCLUSION: Edema-like bone marrow abnormalities of the foot predict long-, lasting pain. Analysis of the image patterns of such abnormalities allows prediction of the clinical outcome to a certain degree.