MRI Distribution of Foot Bone Marrow Edema of Presumed Algodystrophic/BMES-Like Origin: A Small Retrospective Case Series with 3-Month Clinical Follow-Up

Background and Objectives: Foot bone marrow edema of presumed algodystrophic or bone marrow edema syndrome-like origin is clinically difficult to classify, and the relationship between MRI extent, pain severity, and functional impairment remains insufficiently defined. This study aimed to describe MRI distribution patterns and short-term clinical changes in a small real-world cohort of patients with persistent NSAID-resistant foot pain and presumed algodystrophic/BMES-like bone marrow edema. Materials and Methods: This retrospective single-center observational cohort study included 19 consecutive patients with persistent foot pain; MRI-demonstrated bone marrow edema; inadequate response to NSAIDs; management with a multimodal protocol that included neridronate, vitamin D supplementation, and, in selected patients, adjunctive physiotherapy and magnetotherapy; and available 3-month follow-up. The protocol consisted of intramuscular neridronate 25 mg once daily for 16 consecutive days, resulting in a total cumulative dose of 400 mg, together with vitamin D supplementation. Eleven patients also underwent adjunctive physiotherapy and magnetotherapy. MRI findings were categorized by anatomical location group, multilocalization, and compartment involvement. Clinical outcomes included baseline and 3-month Visual Analog Scale scores, WOMAC scores, and descriptive changes in NSAID use. Nonparametric paired and exploratory subgroup analyses were performed. Results: Mean age was 51.3 ± 14.9 years, and 52.6% of patients were female. MRI showed predominant midfoot involvement, with the navicular and third cuneiform most frequently affected. Median VAS changed from 8.0 at baseline to 3.0 at 3 months, and median WOMAC changed from 80.0 to 41.0; because no control group was available, these paired changes should be interpreted descriptively. Daily NSAID use decreased from 78.9% at baseline to 0% at follow-up. These findings describe clinical improvement after a multimodal management approach but do not establish the independent treatment effect of neridronate. In exploratory analyses, only two patients had multi-compartment involvement; therefore, any apparent pain-severity signal in this subgroup was considered unstable and hypothesis-generating only. Edema location group and multilocalization were not statistically associated with VAS or WOMAC outcomes. Conclusions: In this small retrospective single-center case series, presumed algodystrophic/BMES-like foot bone marrow edema most commonly involved the midfoot, particularly the navicular and cuneiform region. Pain scores, WOMAC scores, and daily NSAID use decreased over 3 months after multimodal care. However, the uncontrolled design, small sample size, concomitant vitamin D supplementation, adjunctive physiotherapy or magnetotherapy in many patients, and self-limiting nature of BMES-like conditions prevent attribution of these changes to neridronate or to any single treatment component. The apparent relationship between multi-compartment edema and greater pain severity was based on only two patients and should be regarded only as a weak exploratory observation.