Sport injury types from athletic participation include acute and stress injuries. Acute injuries are the same as those that occur in nonsporting accidents. Stress injuries result from repetitive microtrauma and are unique to sports medicine. These injuries are the focus in this article.
Contusions are common injuries and usually heal quickly and completely. Secondary hematomas are less common in children, presumably due to enhanced hemostatic control in children. Rarely do contusions lead to formation of myositis ossificans. This is most common in the quadriceps. Avoid prolonged immobilization. These lesions mature over time. They may be confused with osteogenic sarcoma.
Ligament injuries Because ligaments are two to three times stronger than bone in children, avulsion fractures are common during growth. Ligaments tend to fail suddenly, in contrast to physeal injuries, which occur with more slowly applied loads. Ligamentous injuries can be graded as follows:
Grade I represent stretch injuries without disruption of fibers that cause tenderness and swelling but without detectable instability.
Grade II are partial tears that allow greater mobility but with a definite endpoint.
Grade III are complete tears involving greater soft tissue injury, including the joint capsule and leading to joint instability.
Ligament injuries are most common around the ankle and knee and, when associated with capsular disruption, cause joint instability. They may coexist with bony injuries, as seen in tibial spine fractures. When the tibial spine is avulsed, the anterior cruciate ligament is stretched, leading to residual laxity following bony union.
Bone injuries Acute bony injuries can fall into the same patterns as those occurring from accidental trauma in nonathletic situations.
Musculotendon injuries can occur at many sites. Complete separations are rare, and healing usually occurs spontaneously because no discontinuity occurs.
Synchondrosis disruptions Accessory ossification centers may become separated from their parent bone. The classic examples are the bipartite patella, accessory tarsal navicular, and accessory ossicles below the ankle malleoli.
Physeal injuries are classified by the fracture patterns . Repetitive stress injury may damage the growth plate in a unique fashion. These stress-induced physeal injuries are most common about the wrist and upper humerus in the child. Stress results in a disruption of the growth plate, as seen in type 5 injuries. Unlike the usual simple physeal fracture, the growth plate becomes widened, irregular, and tender but not grossly unstable. Such injuries may result in physeal damage and altered growth. Type 5 injuries occur in the distal radial epiphysis in gymnasts and in the proximal humeral epiphysis in pitchers.
Traction and compression bone injuries Traction injuries may be acute or chronic and cause bony failure or inflammation at the tendon-bone junction. Compression injuries are usually chronic, with the classic example being the lateral compartment of the elbow in “little league elbow.” Throwing causes compression of both the capitellum and radial head, which may cause vascular damage and bone necrosis.