Trauma or overloading of subchondral bone regions due to cartilage degeneration in combination with limb deformity can lead to the development of subchondral microfractures and bone marrow lesions. The macrophages, monocytes, and osteoclast precursors in the bone marrow stroma react by releasing cytokines and initiating an inflammatory reaction, which leads to a capillary leak and the release of fluid into the bone marrow interstitium (Bartl et al. Knochenmarködem – Formen, Pathogenese, Diagnostik und Therapie. Heidelberg: Springer, 2023; Thiryary et al. Eur J Radiol 67:62–67, 2008). An increasing bone marrow edema leads to increased fluid pressure in the bone compartment, causing painful irritation of the afferent nerve fibers in the bone marrow.