Radiological osteoarthritic knee joint changes in high school and collegiate sumo wrestlers: The observational study

We examined the effects of sumo on their knee joints, and investigated the relationship between radiological changes and knee joints symptoms, and the relationship between knee radiological changes and the physical characteristics of the wrestlers. Fifty-six high-school and 128 college freshman sumo wrestlers who belonged to the Japanese Sumo Federation. To evaluate radiological changes in the knee joints of high-school and college freshmen sumo wrestlers. They underwent routine radiographic examination of their knee joints and were instructed to answer a questionnaire regarding their knee symptoms as a medical check. The mean height, weight, body mass index (BMI), and sumo career/experience of the participants were 174.1 cm, 106.9 kg, 35.1 kg/m2, and 7.9 years, respectively. Twenty-five high-school (44.6%) and 54 collegiate (42.2%) sumo wrestlers had some knee symptoms, which was significantly associated with sumo career as a risk factor. Five high-school (8.9 %) and 18 collegiate (14.1 %) sumo wrestlers had joint space narrowing. Considering the relationship between knee symptoms and radiological changes, significant correlations between osteophyte formation and bony sclerosis and knee symptoms were observed. According to the Kellgren-Laurence (KL) classification, 7 high-school (12.5%) and 26 collegiate (20.3%) sumo wrestlers were grade 2, 3, or 4. The risk factors of degenerative radiographic changes in the knee joints of the participants were heavyweight, large BMI, and older age. The knee osteoarthritic changes had already appeared in 12.5% high-school sumo wrestlers at the admission.