Young athletes with anterior cruciate ligament (ACL) tears face a unique problem. Surgery to repair or reconstruct the damage can disturb bone growth. But delaying surgery until bone growth is completed can put the joint at risk of further damage without a stable ligament.
What's the answer to this dilemma? This study from Children's Hospital of Philadelphia (CHOP) may shed some light on the problem and the solution. Orthopedic surgeons treating children at this hospital went back and looked at the records of 70 children treated for complete ACL tears.
All patients included in the study were 10 to 14 years old. They all had surgery to reconstruct the knee. The key feature reviewed was the timing of the surgery (early or late after injury). Results were analyzed and compared for timing between injury and surgery.
All kinds of other information was gathered and evaluated as well. For example, data collected included the usual demographic information (age, gender, history of injury, side of injury). It was also noted if the child had episodes of the knee "giving way" or "shifting" (a sense of knee instability). And, of course, observations of other knee injuries (e.g., meniscus, articular cartilage) from X-rays or surgeon visual inspection during surgery were also noted.
After sorting through all the data and making many calculations, it was determined that delaying surgery more than 12 weeks from the time of injury may create many more problems than it solves. There is a greater risk of damage to other areas of the knee (e.g., the meniscus). In fact, the number of massive meniscal tears that cannot be repaired increased dramatically in the children who had delayed knee reconstructive surgery.
The cut-off time seemed to be 12 weeks. In other words, children who had knee reconstructive surgery within 12 weeks of their ACL tears had less risk of other injuries, less severe damage, and better overall results.
One other observation made during this study had to do with return-to-sports before surgery. Children treated for ACL tears at this hospital were routinely told not to engage in any activities that could put their already injured knee at risk for further damage. They were advised to avoid running, jumping, or any activities that involved pivoting or cutting motions of the knee.
Despite these guidelines, significant additional injuries were reported. It's not clear if this is because the children ignored the counsel of their surgeons or if the everyday activities of children this age are enough to cause ongoing damage.
There is a tendency for children this age to have more ligamentous laxity (looseness) anyway, so it's possible that without an intact ACL, just normal movement increased the risk of other soft tissue injury. And, of course, the surgeons are aware that children find interesting and creative ways to do what they want to without exactly violating the surgeon's warnings and perhaps without realizing the full effect of their actions.
The authors note that more and more children are showing up with ACL tears. There are more children participating in sports, in more demanding contact sports, and in year-round sports activity. With better diagnostic imaging, earlier diagnosis is now possible. That means the decision whether to carry out early reconstruction versus delay treatment until skeletal maturity is more important than ever.
The medial meniscus plays an important role in stabilizing the knee, especially the knee without an intact ACL. Without a fully functioning ACL, the meniscus is at risk for injury and that leads to damage of the articular (surface) joint cartilage. The potential for early osteoarthritis is there, too.
Weighing the potential risk of disturbing growth centers against further injury and more severe damage to the knee, the authors concluded that delaying treatment until skeletal maturity is not advised in all cases. The risk of further meniscal damage creating an unstable knee with delays past 12 weeks must be considered on a case-by-case basis.
Managing complete ACL tears in children who have not reached full bone growth remains a challenging affair. More study is needed to further identify the odds of associated knee injuries if the ACL reconstruction is delayed. If possible, determining the exact best timing for surgical treatment would be helpful. Every surgeon does things slightly differently even when seemingly performing the exact same surgery. Therefore, assessing surgical technique may be an important factor as well.
Reference: J. Todd R. Lawrence, MD, PhD, et al. Degeneration of the Knee Joint in Skeletally Immature Patients with a Diagnosis of an Anterior Cruciate Ligament Tear. Is There Harm in Delay of Treatment? In The American Journal of Sports Medicine. December 2011. Vol. 39. No. 12. Pp. 2582-2587.