Cam morphology of the proximal femur is characterized by an aspherical femoral head and flattening of the femoral head-neck junction. This atypical shape lends itself to hip joint impingement during flexion and internal rotation and is a well-recognized precursor for early onset osteoarthritis due to repetitive joint wear-and-tear. While surgical treatments have been established, the etiology of this morphology remains unknown. Due to its high prevalence in elite-level adolescent athletes (namely ice hockey, basketball, and soccer players), a causal relationship likely exists between the mechanical stresses associated with these aforementioned at-risk sports and cam development. These stresses are presumably responsible in part for the growth plate changes which precede the bony changes indicative of cam development. To date, no studies have:​ 1) measured hip motion during at-risk sports activities or 2) developed methods to measure changes in three-dimensional growth plate shapes.

This dissertation focuses on the mechanically driven theory that altered hip joint loading associated with at-risk sports practices during adolescence leads to changes in growth plate shape that precede the bony abnormalities indicative of cam. A pervasive method for measuring hip joint motion with wireless sensors was validated and used to analyze hip motion of adolescents during ice hockey, basketball and soccer sports practices (at-risk adolescents) and during after-school activities (recreationally active controls). A method was developed to assess three-dimensional growth plate morphology and applied to compare growth plate shapes of adolescent at-risk soccer players and typically active age-matched peers. Understanding the etiology of cam morphology could lead to training regimens and/or therapies that have the potential to prevent or reduce its incidence. Such therapeutic approaches have implications for reducing the number of individuals who develop osteoarthritis later in life after participating in at-risk sports during adolescence.