Bone, Joint and Muscle Conditions

PCL Injuries

What is an PCL injury?

PCL injuries are damage to the posterior cruciate ligament (PCL) in the knee. The PCL is one of four main ligaments that keep the knee stable.

  • To understand PCL injuries, it helps to know a little about how the knee works.

    The knee is a large joint where the shinbone (tibia) meets the thighbone (femur). Two ligaments run along either side of the knee:

    • The medial collateral ligament (MCL) is on the inside and keeps the knee from bending in.
    • The lateral collateral ligament (LCL) is on the outside and keeps the knee from bending out. 

    Two ligaments – the PCL and the anterior cruciate ligament (ACL) – cross each other in the middle of the knee. They work together to keep the shinbone attached to the thighbone.

    The PCL connects the back part of the shinbone to the front part of the thighbone so that the shinbone does not slide behind the thighbone.

  • When the knee is forced into an unusual position, the PCL and other ligaments can tear, either partially or all the way. In children, PCL injuries most often happen during high-speed sports, such as basketball and soccer.

    A blow to the front of the knee – for example, from hitting the dashboard during an automobile accident or falling hard on a bent knee during a football game – can also injure the PCL.

  • Teenage athletes who participate in high-speed sports are more likely to injure their PCL than other young people. In teenagers especially, accidents also cause PCL injuries.

    Teenagers are more likely to injure their PCL than children who are younger than age 12. Younger children more often break the bone where the PCL attaches.

PCL Injuries at Seattle Children’s

Seattle Children’s treats the full range of bone, muscle and joint conditions, including MCL, PCL and ACL injuries.

    • Your child is cared for by an orthopedics team, including pediatricians, pediatric orthopedic surgeons, nurse practitioners, physician assistants, nurses and physical therapists.
    • To restore your child’s health and function, we use nonsurgical methods, like physical therapy (PT), including sports PT, whenever possible. We have the largest team of physical therapists in the Pacific Northwest who specialize in the care of babies, children, teens and young adults.
    • Children and teens don’t usually need surgery for PCL injuries. If your child does need surgery, we have pediatric orthopedic surgeons with expanded fellowship training in sports medicine and the experience to repair knee ligaments.
    • A child’s knee injury is more difficult to treat than an adult’s. This is because doctors must avoid injury to the growth plates on children’s bones above and below the knee. Here, your child’s team has special training in the medical and surgical needs of young people.
    • We have the largest group of board-certified pediatric radiologists in the Northwest. If your child needs imaging that uses radiation, we use the lowest amount possible (PDF) to produce the best image.
    • Athletic trainers from our Sports Medicine Program work at dozens of area schools, teaching conditioning, assessing and treating injuries and referring athletes to medical providers, all with an eye to keeping your child active for years to come.
    • Your child may be more likely to need surgery if they injured their PCL along with other parts of their knee. We are careful to determine whether your child needs surgery.
    • Our surgical methods limit the risks of injury to growth plates. This increases the chances that your child will be able to return to sports.
    • Our rehabilitation programs are designed so that your child will recover range of motion, rebuild strength and stability, restore balance and regain confidence in using their knee.
    • To help your child return to play quickly and safely, we do more than treat their current injury. We focus on preventing repeat or new injuries.
    • For your convenience, our doctors see patients at several locations around Washington. Seattle Children’s sports physical therapy is available in Seattle, Bellevue, Everett and Federal Way to make ongoing rehab easier for you.

Symptoms of PCL Injuries

If your child’s knee suddenly swells after an accident or injury, they may have a torn PCL or another serious knee problem. Besides swelling behind the knee, symptoms of PCL injuries include:

  • Pain in the knee
  • Knee feels wobbly or unstable

Diagnosing PCL Injuries

To help protect your child from more injuries that could hurt growing bones and joints, it is important to get a thorough evaluation and proper treatment.

  • When you and your child come to our clinic, we:

    • Ask what happened before the knee began to swell and hurt.
    • Examine your child’s knee. To doctors trained in sports medicine, knees with PCL tears often feel loose.
  • We cannot be sure that your child has a torn PCL until the swelling in the knee has gone down. This usually takes 7 to 10 days. At that time, we may take:

    • Radiographs of your child’s knee to get more information on what is wrong
    • An MRI (magnetic resonance imaging) scan if it is not clear that the PCL is torn or if we think your child may have other injuries

Treating PCL Injuries

We treat mild PCL injuries through physical therapy, including sports PT, whenever possible. Surgery is not usually used to treat PCL injuries that don’t involve other parts of the knee.

  • Most children with a PCL injury who have no other injury to their knee recover well after taking part in a rehabilitation program. At Seattle Children’s, our rehabilitation specialists provide regular physical therapy designed especially for your child.

    Your child will have regular physical therapy at our dedicated sports gym. Most likely, your child will have physical therapy sessions 2 times a week for 12 weeks.

    Afterward, our therapists will give your child a set of specially designed exercises to do at home until the thigh muscles in the front (quadriceps) and back (hamstrings) have regained at least 80% of the strength of the uninjured leg, as measured by tests of strength and coordination.

    Our doctors will watch your child closely to make sure they are healing well. Children can usually return to their normal activities in 6 to 12 months.

  • Surgery is not usually used to treat PCL injuries that happen by themselves. But if an injury moves the piece of bone the PCL is attached to far from its original resting place on the shinbone, your child may have surgery to put it back and attach it again.

    If the injury happens along with an injury to the ACL or another part of the knee, your child may have surgery to make their knee stable with the least possible risk of affecting their growth.

    After surgery, your child will have physical therapy.

Contact Us

Contact Orthopedics and Sports Medicine at 206-987-2109 for an appointment, a second opinion or more information.

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