Imaging features of avulsion injuries

Avulsion injuries are common among participants in organized sports, especi ally among adolescent participants. Imaging features of both acute and chro nic avulsion injuries of the pelvis, knee, ankle and foot, shoulder, and el bow were evaluated to help distinguish these injuries from more serious dis ease processes such as neoplasm ana infection. At radiography, acute injuri es (ie, those resulting from extreme, unbalanced, often eccentric muscular contractions) may be associated with avulsed bone fragments, whereas subacu te injuries have an aggressive appearance that may include areas of mixed l ysis and sclerosis, Chronic injuries (ie, those resulting from repetitive m icrotrauma or overuse) or old inactive injuries may be associated with a pr otuberant mass of bone and may bear a striking resemblance to a neoplastic or infectious process, Although not usually required, computed tomography i s helpful in the diagnosis if radiographic findings are equivocal or if the injury is not in the acute phase. MR imaging is best suited for the evalua tion of injuries to muscles, tendons, and ligaments. Recognition of charact eristic imaging features and familiarity with musculotendinous anatomy will aid in accurate diagnosis of avulsion injuries.