Treating a Torn ACL Knee in Children and Teens

Knee Surgery and Rehabilitation

Properly treating an anterior cruciate ligament (ACL) tear is essential to restoring knee joint stability. Given the improved techniques to repair this band of tissue, surgery is a common treatment following an ACL injury—even in young people.

Research shows that it's better to fix the ACL rather than wait, and that waiting itself may cause further damage to the growth plates—the areas of active bone growth in children. The approach used may be different than for adults, however.

This article explains the types of available ACL surgery for children and teens, and why it may be recommended. It also looks at strategies that can help your child heal after ACL surgery.

Teen girl playing soccer
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ACL Treatment Options

An ACL injury can range from a relatively mild sprain to a complete tear that makes the knee unstable. Treatment depends on how serious the injury is.

The decision on how to treat an ACL injury is determined by a physical exam, which may include several tests used to evaluate stability and motion. A healthcare provider also will look at X-ray and magnetic resonance imaging scans to better understand the degree of ACL damage.

Surgery

One of the key criteria for deciding whether or not surgery is needed is the extent of the damage to the ACL. Injuries are graded from 1 (a minor sprain) to 3 (a full ACL tear).

If your child has a grade 3 tear, then surgery is almost always needed to repair the ACL and unstable knee.

Surgery for a full ACL tear tends to be the best option in people who:

  • Are young and active, as most teens and children are
  • Participate in sports that involve a lot of jumps, turns, and rapid speed or direction changes (e.g., soccer, basketball)
  • Experience significant knee instability

A partial grade 2 ACL tear is rare, but surgery may be the best course of action in some cases. Grade 1 injuries do not require surgery.

Non-Surgical Treatments

Non-surgical treatment options are more appropriate for lower-grade injuries.

First and foremost is the RICE method. This involves:

  • Rest: Avoiding weight bearing on the injured knee
  • Ice: Applying ice packs to help decrease pain and swelling
  • Compression: Using an elastic bandage or compression wrap around the knee
  • Elevate: Lying down with the injured knee propped up

These interventions may be all that's needed, or they can be the initial care given to your child before a healthcare provider is able to further treat the ACL injury.

Wearing a brace at the joint can keep the knee stable while the ACL injury heals, if needed. This is something that would be provided or prescribed by a practitioner after your child is evaluated.

Physical therapy (PT) may also be helpful in some cases. It may be sufficient enough to treat a relatively minor ACL injury. It may also be appropriate if surgery is recommended for your child, but you decide against it, or if your child cannot undergo a procedure for some reason (e.g., poor overall health).

Recap

Not all ACL injuries require surgery, but a full tear of the ACL almost always will.

Types of Surgery

In most cases, ACL repairs technically aren't repairs at all. They involve reconstructing, or replacing, the affected tendon with a new one. In both children and adults, this is usually done as an arthroscopic surgery.

Instead of making a large incision so that they can see the ACL directly, a surgeon makes a number of small incisions at the knee joint. A tiny camera is threaded through these openings so that the surgeon can view the ACL on a monitor. Long, thin surgical tools are also inserted.

In addition, the surgeon drills small holes to replace the damaged ACL and reconnect the joint.

There are two types of surgery used to place the new tendon: autograft and allograft. Each has its benefits and drawbacks.

In either case, ACL repair is considered a minimally invasive surgery. It can typically be done in a few hours on an outpatient basis (meaning an overnight stay is not required).

Autograft

With autograft surgery, the ACL is replaced by using a tendon that is taken from your child's own body. This tendon will most often come from the knee, the hamstring (back of the thigh), or the quadriceps (front of the thigh).

Since the tendon is your child's own, the risk of infection is reduced.

Recovery tends to be smoother, but longer, as the body has not one but two surgical sites that need to heal.

Autograft surgery tends to be less expensive than allograft surgery.

Allograft

With allograft surgery, the tendon used to repair the ACL is sourced from an organ donor.

On the one hand, this means a shorter time in surgery and an initial recovery that's less painful.

On the other, the body often takes longer to integrate the donor tendon into the newly repaired joint than it does with an autograft.

Autograft
  • Tendon taken from patient

  • Less risk of infection

  • More extensive recovery

Allograft
  • Tendon comes from a donor

  • Shorter surgery time

  • Body takes longer to integrate

Modification to Protect the Growth Plates

Until their bones stop growing, children and teens are considered skeletally immature.

Surgeons were hesitant to perform ACL repair in young people in the past, as existing techniques used in adults didn't sufficiently spare the growth plates. (These areas of bone growth only close in the mid- to late-teen years.)

This is no longer a significant concern. Research has shown that surgery is the better option in most cases, and newer techniques help protect the still-growing tissue.

Today, surgeons often perform what's called a transphyseal ACL reconstruction on young people. This means they drill only small holes in parts of the active growth plates in an effort to protect them as much as possible.

That said, some researchers have instead suggested that the more standard transtibial technique, which uses drill angles that better protect the growth plates, may be safer in younger people who have ACL repair surgery.

While more research is needed to better understand the difference in teens and children, it's important to talk with your surgeon about the technique they plan to use and why.

Recap

A surgeon will often use a slightly different technique for a child than they would use for an adult. This is to spare still-growing bone tissue.

Post-Surgery Therapy

Children and teens, in particular, are eager to get back to sports and other activities after an ACL injury. They may think surgery is the end their treatment, but it's not.

Most young people will need physical therapy to restore as much function as possible, but there are differences when compared with what adults need to achieve that.

Strengthening the front thigh muscles, for example, may take longer in young people than it does in adults. And targets across time may vary widely when it comes to range of motion exercises and how long they continue.

Guidelines developed at Children's Hospital of Philadelphia call for keeping the knee braced and pain managed in the first week after surgery. Thereafter, activity levels and targets should be increased during a recovery period. A therapist will outline a specific plan for your child.

PT is a significant commitment that typically lasts for weeks and months. If you are considering surgery for your child's ACL tear, be sure to discuss PT requirements with their healthcare provider and make your child aware of this next chapter in their recovery.

Many factors will be key to your child's success, but perhaps none is more important than family support.

Prognosis

The prognosis for teens and children who have ACL surgery is generally good. One study found that 96% of child athletes who undergo ACL reconstruction are able to return to sports at the same skill level after nine to 12 months of recovery.

There is a possibility of the ACL being reinjured, but the risk of meniscus tears and cartilage injury because of an unrepaired injury in an unstable knee is likely higher.

Holes drilled during surgery may affect the growth plates in the affected knee joint. This could lead to slightly different leg lengths or angular deformity, which may cause knock knees (genu valgus) and bow legs (genu varus).

These conditions progressively worsen with further growth and could lead to increased risk of problems such as joint damage and arthritis.

Summary

Surgery is generally accepted as safe for teens and children who have a torn ACL that needs repair. It may not be necessary in all cases, but when it is, there is a good chance the knee function will be restored.

The procedure is much the same as it is in adults, with some changes in how the surgery is done to protect the still-growing bones as much as possible.

The ACL repair isn't the end of the road, though. In some ways it's just the beginning. Your child's recovery will likely require physical therapy once the procedure is complete, and that may take the better part of a year, depending on PT recommendations.

A Word From Verywell

When considering surgery for your child because of a torn ACL, it's important to remember that there are risks to the surgery because their bones are still growing. But there are risks that are perhaps more serious if you wait. Talk to your healthcare provider before making a decision.

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6 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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Additional Reading
  • American Orthopaedic Society for Sports Medicine (AOSSM) Annual Meeting, July 2009.