MISCELLANEOUS RHEUMATIC DISEASES272. BONE MARROW OEDEMA SYNDROME OF THE FOOT AND ANKLE: OUR CLINICAL EXPERIENCE USING A SINGLE DOSE OF INTRAVENOUS ZOLENDRONIC ACID

Abstract

Background: Bone marrow edema syndrome (BMES) of the foot and ankle is a rare non-traumatic syndrome, characterized by joint pain with weight bearing and diffuse reversible BME pattern on magnetic resonance (MRI) images. The aetiology of primary BMES remains uncertain. Ischaemia has been suggested as an initiating factor. Various studies show histological findings to include abnormal vascularity, edema and increased focal bone turnover. The purpose of this study was to assess the pattern of BMES over time in a cohort of patients and the benefit of a single dose of intravenous (IV) Zolendronic acid in this group. Method(s): Retrospective analysis of 8 patients (mean age 51 years) diagnosed with foot and ankle BMES on MRI over a 5-year period up to 2016 using hospital records. The diagnosis of BMES was made following clinical and radiological assessment by excluding other causes of bone marrow edema such as fractures, systemic and local inflammation and infection. All patients had MRI and these images were interpreted by specialist musculoskeletal radiologists. Patients with risk factors for osteoporosis underwent bone mineral density scan (DEXA). Clinical and MRI evaluation was undertaken at 3 and 6 months to assess treatment response. Result(s): Six patients (75%) patients were female and two (25%) were male with a mean age of 41.5 and 32.5 years, respectively. The average duration of symptoms was 14 months from the onset to diagnosis. The most common bone affected was the talus (75%) and multiple bones affected in 7 (87%) patients. All patients were given IV bisphosphonate as treatment. The mean time to resolution of pain in patients treated with Zolendronic acid (7 patients) was 2.4 months. One patient failed to attend follow-up and one patient had poor response to intravenous bisphosphonate requiring surgical intervention. Six patients (75%) showed clinical and radiological response (MRI) at 6 months following bisphosphonate therapy Conclusion(s): BMES is uncommon but must be considered by clinicians while evaluating patients with unexplained persistent foot and ankle pain on weight bearing, despite normal plain radiographs. There is no current guidance on the management of BMES. The only investigation which has been helpful is MRI scan of the affected area, which the clinicians should strongly consider while evaluating patients. Although we have demonstrated excellent response to IV bisphosphonate therapy in our case series of patients, there is a need for further good quality studies in the management of BMES.