Region-specific morphological differences of tibial cartilage in dancers: a quantitative MRI study

Long-term dance training imposes specific mechanical loads, such as repetitive jump-landings and torsional forces, on the tibial cartilage. However, the quantitative morphological alterations in tibial cartilage and their associations with training duration remain unclear. This study employed three-dimensional morphometric measurements to evaluate differences in cartilage volume and thickness, as well as their associations with years of training. Thirty professional and high‑level amateur dancers and 30 matched controls (matched for sex, age, BMI) underwent bilateral knee MRI. Cartilage volume and thickness were measured using SYNAPSE 3D (V6.7.0017CN, FUJIFILM). Following reliability assessment, between-group differences in cartilage morphology were compared, and associations between training duration and morphological parameters were examined within the dancer group using linear mixed‑effects models. Intra-observer repeatability was excellent (ICC 0.923–0.999, CV < 5%), and inter-observer reliability was good to excellent (ICC 0.825–0.963). The dancer group showed significantly larger cartilage volumes than controls for the all tibia and all subregions (all tibia: 589.17 mm 3 , P = 0.002; medial: β = 280.98 mm 3 , P = 0.001; lateral: β = 308.21 mm 3 , P = 0.01), and greater thickness in the medial (β = 0.11 mm, P = 0.04) and posteromedial (β = 0.17 mm, P = 0.002). Side-specific analyses yielded generally consistent results for the left and right knees. Longer training duration was positively associated with medial, anteromedial, and posteromedial tibial cartilage volume, as well as medial and posteromedial thickness ( P < 0.05). This study found that long‑term dance training is associated with increased tibial cartilage volume predominantly within the medial compartment and elevated medial‑side cartilage thickness, and these medial‑region changes are positively associated with years of training. These findings reveal the spatial heterogeneity between volume and thickness in spatial distribution, as well as the cumulative remodeling effect of dance-specific loading on cartilage. These findings suggest that medial tibial cartilage may represent a priority region for future biomechanical and preventive‑training investigations.