Prevalence of Hip Skeletal Deformity in Japanese Male Collegiate Long-Distance Runners

This study aimed to examine whether hip deformity has already developed in Japanese male freshman collegiate long-distance runners and to investigate the association with their sports history. A total of 57 elite freshman collegiate long-distance runners participated. We collected sports history data during adolescence using a questionnaire, and hip images were measured using dual-energy X-ray absorptiometry (DXA). Cam morphology was defined by visual scores of the anterior head-neck junction, classified as: (1) normal, (2) flattening, and (3) prominence. Pincer morphology was defined as a bony prominence or osteophyte-like protrusion at the acetabular rim. Cam morphology based on visual scores was found in 78 of 114 hips (68.4%; 40 right, 38 left). Pincer morphology based on visual scores was found in 73 of 114 hips (64.0%; 39 right, 34 left). There was no significant association between hip deformity and sports participation history (P > 0.58). In an additional exploratory non-athletic cohort, a similarly high prevalence of cam and pincer morphology was observed (cam: 14 of 18 hips [77.8%]; pincer: 13 of 18 hips [72.2%]). These may indicate that factors beyond participation in multidirectional sports, including internal factors, could contribute to hip morphology.