Tibial hemodynamics during walking in knee osteoarthritis with bone marrow lesions: A cross-sectional study

Impaired subchondral bone perfusion contributes to bone marrow lesions (BMLs) in knee osteoarthritis (KOA); however, it has been assessed only under static and non-weight-bearing conditions. Dynamic, weight-bearing conditions such as walking may further compromise perfusion; therefore, understanding the resulting hemodynamics is crucial to the pathophysiology of BMLs; however, they remain unknown. This study characterized the hemodynamics of the medial aspect of the tibial tuberosity during walking in patients with KOA and BMLs using near-infrared spectroscopy (NIRS). In this cross-sectional study (March-July 2025), we compared the tibial hemodynamics during walking across four groups: young adults (n=18), older adults (n=18), KOA without BMLs (n=18), and KOA with BMLs (n=20). We used NIRS to measure changes in tissue oxygenation index (TOI) during a 3-min walking phase and a 5-min post-walking phase. BML volume was quantified using magnetic resonance imaging in the KOA-BML group only. Analysis of data from 74 participants revealed a significant group-by-phase interaction for all hemodynamic parameters using linear mixed models. Compared to the three control groups, the KOA-BML group showed a greater decrease in TOI (vs. young: MD -14.43, 95% CI [-17.30, -11.56]; vs. older adults: MD -11.94, 95% CI [-14.67, -9.21]; vs. KOA: MD -9.99, 95% CI [-12.73, -7.25]). Moreover, a lower TOI during walking correlated with a larger BML volume (r = -0.634, 95% CI [-0.840, -0.266]). Pathological hypoxia of the medial aspect of the tibial tuberosity during walking appears specific to patients with KOA-BMLs. This dynamic impairment correlates with BML volume.