A pelvic avulsion fracture occurs when a small piece of bone is pulled away from the main pelvis bone by the force of a powerful muscle contraction. This most frequently happens to adolescent athletes whose bones are still developing and whose growth plates are softer than the attached tendons. Common sites include the bony points where the hip flexors, hamstrings, or abdominal muscles attach.
Patients usually experience a sudden, sharp onset of pain during an explosive movement, such as sprinting, kicking a ball, or jumping.
Audible Pop: A distinct snapping or popping sensation at the moment the bone fragment detaches.
Point Tenderness: Severe pain when pressing on specific bony landmarks around the hip or groin.
Limited Mobility: Difficulty walking or moving the leg due to intense pain and muscle guarding.
Swelling and Bruising: Inflammation and discoloration that may appear over the site of the fracture.
Weakness: A significant loss of power when trying to use the muscle that pulled the bone away.
Physical Examination
X-rays: The primary tool used to see the displaced bone fragment. Comparison views are often helpful in young patients with developing growth plates.
CT Scan: Used if the X-ray is unclear or if the doctor needs to measure the exact distance of the bone displacement.
MRI: Helpful for identifying the degree of associated muscle and tendon damage, especially in subtle or non-displaced cases.
Unless there is significant displacement, most pelvic avulsion fractures are treated without surgery. The initial phase of recovery requires avoiding any weight on the affected leg to prevent further displacement. Once the bone begins to come back together, physical therapy focuses on regaining flexibility and gradually reintroducing strength training. Total return to sports typically takes three to four months.
Fracture Displacement
Minimal (< 2cm): Rest with crutches for 4 to 6 weeks, followed by progressive physical therapy.
Significant (> 2cm): Surgery may be considered to screw the bone fragment back into its original position.
Chronic Non-union: Surgery to remove or reattach a bone fragment that failed to heal and causes persistent pain.