BMD in Transient Osteoporosis and Bone Marrow Edema Syndrome: A Scoping Review.

Transient osteoporosis of the hip (TOH), regional migratory osteoporosis (RMO), and bone marrow edema syndrome (BMES) are increasingly recognized as manifestations of the same underlying condition. Hallmark features include joint pain, bone marrow edema on MRI, and localized demineralization. However, densitometry data in this context are fragmented and difficult to interpret. This study screened 561 publications and identified 188 patients with quantifiable bone mineral density (BMD) data-Z-, T-scores (for patients under 50), or raw values-obtained during active disease and unaffected by treatment. Mixed-effects modeling and linear regression showed significant BMD reductions in symptomatic hips: marginal mean Z/T-scores of -2.12 (95% CI -2.4 to -1.88, n = 48). In pairwise analyses, symptomatic hips had lower BMD than asymptomatic hips: marginal mean Z/T-score difference -1.2 (95% CI -1.7 to -0.8, n = 16) and raw score difference of -0.173 g/cm2 (21% lower; 95% CI -0.214 to -0.132, n = 19). Despite few reports of back pain, spine BMD was also reduced: mean Z/T-score of -1.83 (95% CI -2.1 to -1.6, n = 65). Among perinatal women, spine BMD reached -2.2 (95% CI -2.6 to -1.8, n = 22). No BMD differences emerged between osteoporosis- and edema-related terminology groups, supporting a shared disease mechanism.