Impact of marathon running on morphological variations in the knee joint based on statistical shape modelling

OBJECTIVE: This study investigates the morphological variations influenced by marathon running by establishing a statistical shape model (SSM) of the knee joint for non-marathon-running Chinese women and comparing it with Chinese female marathon runners. APPROACH: Magnetic resonance images of the knee joints of 8 Chinese female marathon runners and 48 female non-marathon controls were collected. A SSM of knee joint geometry was developed for the control group and assessed. Each model was individually fitted to extract the principal component weights, which were analysed using independent sample t-tests and Mann-Whitney U tests to identify significance. The differences of knee joint geometry between the two groups were compared by principal component to assess the impact of marathon running on knee joint morphology. MAIN RESULTS: The SSM of the control group met evaluation standards. Marathon running maybe impacts the geometric structure of the knee joint significantly, notably manifesting as an outward bulge of the lateral femoral epicondyle, expansion of the trochlea and medial tibial, slight concavity of the tibial plateau, increased uniformity of the articular surfaces of the patella, and thickening of the posteroinferior region of the patella by comparisons. SIGNIFICANCE: Marathon running is one of the factors that influences morphological variations in the knee joint because of physiological adaptations to muscle training, with some areas even experiencing pathogenic tendencies of bone expansion. These findings will aid in the early diagnosis of marathon-related diseases, so as to provide an opportunity for early intervention to prevent such conditions. Besides, this can provide new theoretical support for sports medicine and formulate evidence-based exercise regimes.