Avulsion Fracture of the ASIS: Uncommon injury is common to soccer

Two players go down following a violent collision on a 50-50 ball. One player jumps up and pursues the ball while the other is in pain. The player rolls into a fetal position unable to extend his legs. Upon examination, he complains of severe pain over the protruding hip bone on his right side. The player is confused about the pain because there was no direct impact to this area. This would rule out a hip pointer (bone bruise). Palpation of the ASIS (anterior superior iliac spine) provides a small defect in the bone where the sartorius muscle (strap muscle) (see picture 1) attaches to the upper front section of the hip bone. The player is transported to the ER for x-rays and evaluation. The parents and players are told by the on site athletic trainer what was wrong. It took 5 doctors and an MRI scan to finally confirm this diagnosis. Unfortunately, this was a true story and it only emphasized the importance of an awareness of a fairly common soccer injury.

Mechanism of Injury

Often the collision that caused the fracture is hard to describe. There is usually a sudden impact combined with a quick tug of the leg. The most common position of injury is a jerky movement with the hip in extension and external rotation. This puts the sartorius muscle in a full stretch pulling a piece of the bone loose from its origin of the ASIS. As pointed out before, the fetal position gives the most relief from pain. Transportation in this position would afford the player the least amount of pain. There have been instances of this same injury after a defender has taken numerous goal and free kicks against a stiff wind. Combine this with long ball clearances and the strain would be cumulative. The one kick that causes the fracture may or may not be painful enough to stop play due to adrenaline. It will stiffen soon after the game and become quite painful as swelling and tenderness set in.

Treatment

Initial treatment is ice, immobilization and doctor ordered anti inflamatories. Ice should be used for 20 minutes at a time, being careful not to burn or damage the skin. X-rays, MRI or bone scan should be taken to rule out a more extensive injury. It is usually not necessary to totally immobilize the area for healing to take place. Crutches and a hip spica wrap (see picture 2) will help if the injured player has to ambulate (i.e. school, work). Stairs are usually not possible unless they can scoot backwards up them on their rear end. As with any fracture, there is a 4-6 week healing period. When the tenderness has subsided, the doctor may prescribe light exercise on a stationary bike or some other non-irritating platform. When the healing process is complete, a more aggressive strengthening and stretching program can be put in place (see pictures 3&4). You can progress to light running and kicking if they can be tolerated pain free. Finally, full play may resume when fitness and strength dictate such.

In conclusion, always be cognitive to the possibility of an avulsion fracture of the ASIS. An awareness of the mechanics and symptoms of injury will help make a correct diagnosis and allow early treatment.