Quantitative Evaluation of Knee Cartilage in Professional Martial Arts Athletes Using T2 Mapping: A Comparative Study.

Context: Although the relationship between high-impact sports like football and basketball and the development of knee osteoarthritis is well established, the effect of martial arts on the knee joint remains unclear.

Objective: To compare the imaging abnormalities of knee joints and T2 relaxation times of cartilage in professional martial arts athletes and healthy controls.

Design: Cross-sectional study.

Setting: Hospital imaging center.

Patients or other participants: Nine asymptomatic professional martial arts athletes and 18 healthy volunteers.

Main outcome measure(s): We performed 3T magnetic resonance imaging of the knee on both legs of athletes and the dominant leg of controls. The magnetic resonance imaging protocol included conventional sequences used for morphological assessment (cartilage, meniscus, ligaments, joint effusion, and bone marrow edema) and T2 mapping used for quantitatively evaluating the cartilage. Knee cartilage was manually divided into 8 regions, and T2 relaxation times of the corresponding subregions were measured. Fisher exact test and t test were used to compare the frequency of lesions and cartilage T2 values both between groups and between the athletes' limbs. P < .05 was considered significant.

Results: Professional martial arts athletes exhibited significantly higher frequencies of cartilage (55.6% vs 11.1%, P = .023) and ligament lesions (66.7% vs 16.7%, P = .026) compared with the control group. Athletes showed higher T2 values in 3 distinct cartilage segments: the central weight-bearing segment of the medial femoral condyle (P = .006), the medial tibial plateau (P = .012), and the trochlea (P = .032), when compared with the controls. Additionally, the dominant leg of athletes showed significantly higher T2 values compared with the nondominant leg.

Conclusions: The findings demonstrated the impact of martial arts on the knee joint, characterized by higher prevalence of lesions and elevated cartilage T2 values, particularly in the medial compartment. The dominant legs of martial arts athletes seem to have higher risk of cartilage degeneration due to the observed interlimb differences in T2 values.