Dr. Jeremy Burnham co-authored a book chapter on pediatric ACL injuries in the book Knee Surgery – Tricks of the Trade by Dr. James Stannard. The book chapter is titled “Anterior Cruciate Ligament – Tibial Avulsion.”
Tibial spine, or tibial eminence, avulsion fractures are primarily found in pediatric patients. They occur when the ACL tears through the bone attachment site instead of the ligament itself.
Overview of Book Chapter and Basics of Tibial Avulsion and Pediatric ACL Injuries
Avulsions of the tibial spine, often called eminence avulsions in children, are a form of ACL injuries. The attachment area of the ACL to the tibia is larger and more stable than its femoral location, making tibial-sided avulsions a rare variant of ACL injury.
While plain radiographs are often normal in ACL injuries without a segond fracture, tibial avulsion injuries can be seen on plain films as a fracture of the tibial eminence. These injuries often occur in children whose bones have not yet finished growing, which makes them more likely to suffer an avulsion fracture instead of a ligament tear
High-energy trauma that results in hyperextension, valgus, and external rotation forces can cause Tibial avulsions. This type of injury is less common in adults. If there is any fracture displacement, then surgery may be needed.
There are key principles in treating tibial avulsion ACL injuries. You need to understand the patient’s history, do a physical examination, get appropriate imaging, and plan what to do before surgery. Intraoperative preparedness is also important. Knowing the anatomy is vital.
There are two elevations on the tibia: the medial and lateral eminences. The ACL (anterior cruciate ligament) attaches to the medial elevation. The medial and lateral menisci also attach to the tibia at the anterior (front) of the bone, which can make it difficult to repair a tibial eminence avulsion.
Surgical treatment usually involves either stitching or screwing the bone back together. Occasionally, temporary pins are put in place to hold the bone together. This is not the best way to fix the bone, but it is a short-term solution that will eventually need to be removed.
The way you fix an avulsion will depend on what kind of avulsion it is. If it is a piece of cartilage, you can sew it back in place. If it is a bigger piece of bone, you can put screws in to hold it in place. The way you fix the avulsion will also depend on how old the patient is and if their growth plates are open.
Dr. Jeremy Burnham is a board certified sports medicine orthopedic surgeon in Louisiana who specializes in complex knee injuries. In addition to maintaining a busy clinical and surgical practice, he is active in academics and research.