Apophyseal avulsion fractures are usually the result of a sudden forceful concentric or eccentric contraction of the muscle attached to the apophysis. Avulsion fractures of the pelvis are most common in young athletes due to the discordance between an increased muscle strength and an unfused physis at the muscle-tendon-bone unit.
The most common locations were the ischial tuberosity (54%), anterior inferior iliac spine (22%) and anterior superior iliac spine (19%). The least common locations were pubic symphysis (3%), and iliac crest (1%)1.
According to one study, soccer and gymnastics were the most common sports related cause of apophyseal avulsion fractures1.
Note should be made that lesser trochanteric fractures are rare in adults and when an isolated nontraumatic lesser trochanteric fracture is seen in an adult, it is highly suspicious for metastatic disease until proven otherwise.