JAY C. ALBRIGHT, MD

Each year, approximately 150,000 people tear their anterior cruciate ligament (ACL). According to estimates, as well as our experience at The Pediatric Sports Medicine Program at Arnold Palmer Hospital for Children, the rate of this injury in skeletally immature athletes is dramatically rising faster than skeletally mature people. The ACL is the prime stabilizer preventing anterior translation of the proximal tibia under the distal femur. It originates along the posterior aspect of the lateral femoral condyle in the intracondylar notch of the femur. It traverses obliquely to the proximal tibia centrally. In addition to anterior translation it also serves to restrict rotation of the knee. Without an ACL to control these movements of the knee a child or young adolescent only has a 10 percent chance of being able to play or compete at their previous level of activity. They are also more likely to tear either meniscus or damage their cartilage with continued instability events (translation) of the knee known as a “pivot shift.” Unfortunately, arthritis at an early age with permanent disability is likely long-term without treatment.

The typical ACL injury occurs without contact, usually as a deceleration movement whether it is a change of direction, landing from a jump or coming to a sudden stop. It also occurs with traumatic injuries such as getting hit from the side during football or soccer, or during a motor vehicle accident.

ACL injuries are graded according to the amount of motion an examiner is able to produce during diagnostic maneuvers. These include the Lachman’s and anterior drawer tests. A partial tear of the ACL results in increased length or laxity but does not necessarily need surgical intervention. However surgery for a complete tear is typically advisable for most children.

Radiographs are needed of each injury to rule out avulsion of the tibial or femoral insertions of the ACL that can be reduced sometimes surgically with good results. An ACL injury by itself usually results in no radiographic abnormalities. An MRI of the injured knee is a standard of care since over 60-70 percent of ACL injuries will have associated injuries of the meniscal cartilages, or other ligaments of the knee.

Surgical planning includes evaluation of skeletal and physical maturity. The pediatric orthopedic sports surgeon’s biggest challenge is the choice of which type of surgical reconstruction to perform. Children with more than 2 years of growth remaining should not have an adult type of ACL reconstruction in most instances for risk of iatrogenic growth disturbance, leg length discrepancy or malangulation. Bone age studies, Tanner staging and other studies are utilized to estimate amount of growth remaining at the knees. The surgeon may elect to treat the very young child with an isolated ACL tear conservatively, through bracing and physical therapy to try and prevent recurrent pivot shifts until the child is older and able to undergo a more adult type of procedure. Unfortunately, for a child with concomitant injury of other knee structures, surgical intervention is necessary.

There are multiple options for surgical techniques in the very young with an ACL tear, ranging from avoidance of crossing of the growth plates, with or without drilling of tunnels in the epiphysis of the distal femur or proximal tibia, to drilling through the proximal tibial growth plate and going around the growth plate on the femur.

Besides growth disturbance, the other increased risk of surgery that a growing child has when compared to an adult is the potential for the reconstruction to fail, necessitating a revision reconstruction. While rates of success approach 90+ percent in growing children, the adult type surgeries approach 95 percent success rates.
This is of concern particularly in young women who are nearly 6-8 times more likely than young men to sustain an ACL injury in the same sports according to the American Academy of Orthopedic Surgeons. The best results of ACL treatments come from the prevention of the injury in the first place. It is one of the goals of the Children’s Sports Medicine Program at Arnold Palmer Hospital to help the young athletes in Central Florida prevent ACL tears. There are few programs proven to reduce the risk of ACL injuries in young women. These programs involve a type of training called plyometrics or jump training to strengthen children’s legs and improve balance and coordination in order to prevent placing the knee in a dangerous position for the injury as well as improve the athletes’ ability to perform at their best.

Dr. Albright is the Director of Pediatric Sports medicine at Arnold Palmer Hospital for Children. He is one of a handful of physicians in the country with full fellowship training in both pediatric orthopedic surgery and sports medicine. Dr. Albright is recognized as one of the top experts in the country by his peers, serving as a faculty and an expert panel member for national and international conferences and courses.