- An avulsion fracture occurs when the force of a tendon or ligament pulling on the bone is enough to tear part of the bone away. The fractures occur at the projections (known as apophyses) where the tendons and ligaments attach to the bone.
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Right Hip Bone from Gray's AnatomyAvulsion fractures can occur in several places in the body. In the hips, they occur at the anterior superior and inferior iliac spines; at the ischial tuberosities (sometimes called the "sitz bones"); and at the ischiopubic rami, all sites of attachment for large muscles. Other common areas of injury include the elbow, wrist, ankle and foot. - Avulsion fractures occur when more force is applied to a bone than the bone can withstand; it could be said that the muscle is stronger than the bone. Any activity that requires whiplike motion or turning -- such as basketball, baseball (particularly pitching) and ballet -- may result in avulsion fractures, since the forces of the muscle are pulling in a different direction than the bone.
- Young athletes and dancers are prone to these injuries because their bones are still developing and may not be keeping pace with their muscular development. Athletes and dancers in general are more likely to have highly developed muscles and to push the body into extreme positions. Trauma such as a fall or car accident can also result in avulsion fractures.
- Avulsion fractures usually heal without surgery, especially in young people whose bones are still developing. Rest and ice of the affected area are the usual recommendations. If the ligament or tendon has been damaged, surgery may be needed to reattach the bone. These fractures rarely cause problems after healing is complete.
- If you suspect a fracture or injury to a ligament, contact a physician or qualified practitioner immediately. Signs of fracture include pain on use of the part, swelling and discoloration, and decreased mobility.
