Pediatric ACL Injury and Surgery
ACL Reconstruction in Denver, Colorado
The vast majority of medical journal articles pertaining to ACL tears focus on adult injuries. It has been estimated that between 1 and 3% of all ACL tears happen in patients less than 14 years of age. The ACL can tear within its’ substance, or the tear can result from the ligament tearing off its’ bony attachment on the tibia. The latter type of injury is termed a “tibial spine avulsion injury”.
When a pediatric patient suffers a knee injury that is followed by marked knee swelling, fully two-thirds of the time an ACL tear has occurred. Other possibilities include a cartilage injury, tibial spine avulsion, capsule strain or patellar sleeve fracture. Once an ACL tear has occurred, it is important to control swelling (knee joint bleeding), and to see a physician as soon as possible. Many adolescents will confirm the presence of a “wobbly” knee joint, or having an unreliable knee. Examination reveals a positive “Lachman” test in cases of ACL tears.
As seen in the diagram, there are three types of tibial spine avulsion injuries, according to McKeever. Not shown in the drawing is the fact that the ACL attaches onto the tibial spine fragment. A type I avulsion injury results in predictable healing with little need for surgery. In the other extreme, a type III injury requires surgery to reattach the ACL down to the tibia.
The primary challenge confronting surgeons wishing to reconstruct an adolescent’s ACL is dealing with the physes, namely, the “growth plates.” Growth plates are present at the ends of all the “long bones” of the body. There are two primary growth plates around the knee: at the end of the femur and at the top of the tibia. These growth plates are very important in the regular growth of the leg, providing approximately 2/3 of the longitudinal length of the leg (the remaining growth comes from the top of the femur, at the hip, and at the end of the tibia, at the ankle).
Although growth of the leg markedly slows down in late adolescence, the growth plates fuse in our 20th year. Thus, a growth plate injury in early adolescence may potentially affect the length of the leg and may also render it “angularly deformed,” or crooked. This explains surgeons’ reluctance in operating on ACLs in young children. If care is not taken, the shape and length of the leg could be altered. Happily, ACL injuries in children are rare, but they do occur. Until the last decade there was general consensus that children should not be allowed to participate in sports at least until the middle of puberty, at which point the growth plates were less vulnerable to surgery-related injuries.
Why not just wait? Recently several well-performed studies have shown the potentially catastrophic results of placing children in knee braces and “hoping for the best” until the child is in mid-pubescence. When making decisions in medicine, we always compare the natural history of a disease (having an ACL tear), with the treatment of the disease (ACL reconstruction). From a recent medical journal article from The Hospital for Joint Diseases, New York City (ACL Injuries in the Skeletally Immature Patient, Orthopedics 2007):
The natural history of the ACL-deficient knee in the adult patient is well known. It is associated with chronic instability, chondral injury, subsequent meniscal pathology, pain, and joint arthrosis. The natural history of the ACL-deficient knee in the pediatric and adolescent population is similar. Aichroth et al (Journal of Bone Joint Surgery, British, 2002) presented a prospective review of untreated ACL rupture in pediatric and adolescent patients. A group of 23 patients were treated nonoperatively with physiotherapy, rehabilitation, bracing, and activity modification. At mid-term follow-up (72 months), all patients had signs of instability and 10 had progressed to joint arthrosis. The outcomes of nonoperative treatment were so poor that the authors changed their treatment protocol and now advocate early reconstruction. These results corroborate the results reported in earlier studies and highlight the importance of treating this injury to provide a stable knee and avoid further meniscal injury.
I believe studies like these, in combination with smarter ways of reconstructing ACLs in this special population, warrant serious consideration. In addition, I feel it is potential folly to think that a child can be safely treated in a knee brace. Knee braces notoriously fit the pediatric patient poorly, and I find it gut-wrenching to watch an adolescent run around a field with a knee brace that is ill fitting and improperly applied. The data behind knee braces in the adult population are dubious themselves, saying nothing of pediatric knee braces. Bottom line: if a young child has an ACL tear, I believe bracing is of no utility, perhaps even harmful. If surgery is to be postponed, then an aggressive program of no cutting, twisting, turning sports should be maintained. For the typical pediatric patient who has suffered an ACL tear, this type of program may be impossible to comply with. In the vast majority of cases, I recommend precise, careful ACL reconstruction tailored to the patient.
If you are concerned about a pediatric acl injury, please contact us today to speak with our doctor.