Published 7/1/2015
Jennie McKee

Treating ACL Tears in Children: When is Surgery Warranted?

Patients’ skeletal maturity and physiologic development are among factors to consider

The number of pediatric patients who sustain anterior cruciate ligament (ACL) tears is increasing, especially among young athletes who participate in year-round sports that put tremendous strain on their joints. But how to treat these skeletally immature patients—whether with ACL reconstruction or nonsurgical treatments—remains controversial.

Mininder S. Kocher, MD, MPH, associate director of the sports medicine division at Boston Children’s Hospital and professor of orthopaedic surgery at Harvard Medical School, explored both surgical and nonsurgical treatment options in young patients—focusing on the unique challenges that may occur when treating 12-year-old patients, specifically—during the 2015 Pediatric Orthopaedic Society of North America Specialty Day.

Weighing pros and cons
“It’s important to recognize that not all 12-year-olds are the same,” said Dr. Kocher. “Children of the same age may be at various stages of physiologic development.”

Advantages and disadvantages of both surgical and nonsurgical treatments should be carefully considered, he said.

“Surgical treatment can provide knee stability, which enables the child to return to sports and activities,” he said. “Surgery can also treat meniscal chondral injuries.”

Disadvantages of surgery, he said, include the fact the surgeon is performing a complex surgery in a young child.

“In addition,” he said, “the long-term outcomes of surgery are unknown in children, and there is a risk of a growth disturbance.”

Nonsurgical treatments avoid these risks, but may increase the patient’s risk of meniscal chondral injury and subsequent knee instability.

“In addition,” said Dr. Kocher, “nonsurgical treatment restricts activity in these young active patients, which has a psychosocial impact.”

Studying the literature
Dr. Kocher and colleagues published a study in 2005 that involved 44 skeletally immature prepubescent adolescents who underwent physeal sparing and combined intra-articular and extra-articular reconstruction of the ACL with the use of an autogenous iliotibial band graft. At a mean follow up of 5.3 years, the researchers found a 4.5 percent revision rate, high rates of return to sport, and no cases of growth disturbance. They concluded that, in these patients, this surgical technique “provides excellent functional outcome with a low revision rate and a minimal risk of growth disturbance.”

But when surgery is delayed in skeletally immature patients, noted Dr. Kocher, outcomes may be negatively affected. In a study published in 2011, researchers reviewed the records of 70 patients aged 14 years and younger who had undergone ACL reconstruction between 1991 and 2005. The investigators analyzed demographic data, results of MRI scans, and intraoperative findings, and graded meniscal and articular injuries. They identified factors independently associated with intra-articular lesions, and used the Fisher exact test and Kaplan-Meier analysis to identify differences in intra-articular injuries by time, from injury to surgery.

“In this study,” Dr. Kocher noted, “41 percent of patients had ACL reconstruction more than 12 weeks after injury.” The researchers found a significant association between time to ACL reconstruction and medial meniscal injuries, lateral meniscal injuries, and patellotrochlear injuries. Furthermore, the investigators found that a delay in treatment of more than 12 weeks after injury was linked to an increase in higher grade lateral and patellotrochlear chondral injuries as well as the severity of medial meniscal tears.

Another recent study divided 135 young patients into three groups based on timing of surgery after injury: less than 6 weeks (acute), 6 to 12 weeks (subacute), and more than 12 weeks (chronic). The researchers found that subacute and chronic reconstruction patients had higher odds of lateral meniscal tears severity, compared with acute reconstruction patients (1.45 and 2.82 times higher, respectively). Female sex, older age, and any episode of instability were identified as independent risk factors for medial meniscal tears. The researchers concluded that delaying ACL reconstruction was linked to increased risk of chondral and secondary meniscal injuries.

Conversely, studies of nonsurgical outcomes, noted Dr. Kocher, have found that although many skeletally immature patients with ACL tears can cope and return to activity without undergoing ACL reconstruction, they may be at risk for new meniscal tears in the long term. Studies indicate that arthritis is a problem in these patients, regardless of the treatment they receive.

“The rates of arthritis found in these patients at 10 or 15 years, even after ACL reconstruction, are extremely high—more than 50 percent,” noted Dr. Kocher. “But these rates seem to be higher in patients who had meniscal and chondral injury as well.”

In Dr. Kocher’s view, choosing the right treatment approach for a 12-year-old patient with an ACL tear is “a balancing act.”

“With these young children, it’s hard to keep them out of activities, because it affects them psychosocially, and they are at risk of meniscal and chondral injury,” he said.

“So,” summed up Dr. Kocher, “when treating a 12-year-old patient with a complete ACL tear, my recommendation would be to talk about nonsurgical versus surgical treatment. It is important to recognize, however, that nonsurgical treatment may not be conservative—in fact, it may be risky. Physeal-sparing ACL reconstruction may be the appropriate treatment option.”

Dr. Kocher reports potential conflicts of interest. For more information, visit www.aaos.org/disclosure

References for the studies cited in this article can be found in the online edition, available at www.aaosnow.org

Jennie McKee is a senior science writer for AAOS Now. She can be reached at mckee@aaos.org

Bottom Line

  • Controversy exists regarding optimal treatment strategies for children with ACL tears. Factors such as risk of growth disturbance and meniscal and chondral injuries should be taken into consideration when weighing nonsurgical treatment or ACL reconstruction.
  • Surgical management can provide knee stability, enabling the child to return to sports and activities. The long-term outcomes of ACL reconstruction in children are unknown, however, and surgery creates a risk of growth disturbance.
  • Nonsurgical treatment may put the child at increased risk of meniscal or chondral injury and subsequent knee instability. In addition, nonsurgical treatment restricts activity, which has a psychosocial impact.
  • Studies have found delaying ACL reconstruction may be linked to problems such as chondral and secondary meniscal injuries.
  • According to Dr. Kocher, physeal-sparing ACL reconstruction may be the optimal treatment choice for many young patients.


  1. Lawrence JT, Argawal N, Ganley TJ: 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? Am J Sports Med 2011 Dec: 39(12):2582-7.
  2. Anderson AF, Anderson CN: Correlation of meniscal and articular cartilage injuries in children and adolescents with timing of anterior cruciate ligament reconstruction. Am J Sports Med 2015 Feb: 43(2):275-81.
  • MS, Garg S, Micheli LJ: Physeal sparing reconstruction of the anterior cruciate ligament in skeletally immature prepubescent children and adolescents. J Bone Joint Surg Am 2005 Nov: 87(11):2371-9.