Knee and Kneecap Problems

What are knee and kneecap problems?

Many different problems can affect the knee and kneecap (patella), the disc of bone that protects the knee joint and helps the thigh muscles move the knee.

The kneecap is one of three bones in the knee. The others are the shinbone (tibia) and the thighbone (femur). The kneecap sits within a tendon (patellar tendon) at the end of the thighbone, near the front thigh muscle (quadriceps).

  • What causes knee and kneecap problems?

    Sometimes the kneecap is sitting in an unbalanced way, usually too far toward the outside of the knee. This can cause the kneecap to slip out of the joint or put more pressure on the thighbone and the cartilage in the knee. All of these problems can cause pain.

    Tight thigh muscles can also lead to knee and kneecap pain. If the muscles on the front of the thigh (quadriceps) are tight, the kneecap gets pushed hard against the thighbone. Tight muscles on the back of the thighs (hamstrings) force the quadriceps to work harder, which may cause kneecap pain.

    Patellar tendonitis (PDF), or jumper’s knee, happens when the patellar tendon becomes inflamed. It is common in children who do repetitive jumping activities, like jump rope or basketball.

    Patellofemoral syndrome (PDF) is pain at the front of the knee caused by irritation of the kneecap or end of the thigh. Irritation can be caused by overuse of the knee from a repetitive activity, doing weight-bearing work that puts extra pressure on the joint or from a kneecap that is out of alignment.

    In children, spots on the bones around the knee that contribute to growth are weaker than other surrounding bone. If the growth centers (growth plates) become inflamed or irritated, it can cause pain.

    When this happens at the top of the shinbone, the problem is called Osgood-Schlatter syndrome (PDF). When it happens at the bottom of the kneecap, it is called Sinding-Larsen-Johansson syndrome (PDF).

  • Who gets knee and kneecap problems?

    Growing children and adolescents, particularly teenage girls, can have pain around their kneecaps. Children whose knees are bent inward – commonly called knock-kneed – also tend to have the problem. So do children with tight thigh muscles.

Why choose Seattle Children’s for treatment of knee and kneecap problems?

Seattle Children’s Orthopedics and Sports Medicine specialists treat knee and kneecap problems in children, teens and young adults up to age 21.


  • The knee experts you need are here
    • Our sports medicine and sports surgery team includes experienced pediatric , , , , nurses and who know how to evaluate and treat all types of knee and kneecap problems.
    • To restore health and function, we often use nonsurgical methods, like physical therapy (PT), including sports PT, and home exercise programs. We have the largest team of PTs in the Pacific Northwest who specialize in the care of babies, children, teens and young adults.
    • For those who need surgery, we have pediatric orthopedic surgeons with expanded fellowship training in sports medicine.
  • Knee care from birth through young adulthood
    • Our experts have the knowledge, training and skills to treat the youngest children, who are still growing, through young adults in their early 20s. We have special training in the physical, emotional and social needs of young people of all ages.
    • We tailor treatment to each person’s specific problem and consider their age and development. Young people with knee problems may need different care than adults do. When treating a knee problem in a growing child, doctors must take into account the growth plates on bones above and below the knee.
    • For imaging that uses radiation, we use the lowest amount possible (PDF) to make the best image. We have a low-dose radiation X-ray machine, called the EOS. It makes safer full-body images. We also have the largest group of pediatric radiologists in the Northwest.
  • Our approach to surgery improves life for our patients
    • We offer several surgical options for children, teens and young adults who need more than physical therapy, and we are careful to choose the option that best matches each patient’s condition.
    • We recommend surgery only when we believe it will provide the best outcomes. First, we look at each patient as a whole person. The team will take many factors into account. These include how serious the knee condition is, its health effects, if the body is still growing and what results you can expect from treatment.
    • Seattle Children’s surgeons are experienced in  of the knee for young people.
  • Support for the best recovery
    • Your team at Seattle Children’s does more than plan and provide care. We also make sure you and your family understand the condition and treatment options. We support you in making choices that are right for you.
    • Our rehabilitation programs are designed to strengthen muscles around the knee. This helps keep the kneecap aligned and prevent irritation and pain.
    • To help patients return to play quickly and safely, we do more than treat the current problem. 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 at our hospital campus and Odessa Brown Children’s Clinic Othello in Seattle as well as in Bellevue, Everett and Federal Way to make ongoing rehab easier for you.
    • Seattle Children’s supports your family with a range of resources. Our Child Life specialists, Family Resource Center and Guest Services are here to help.
  • Research to improve knee care
    • Our team members partner with experts at other children’s hospitals on multicenter studies. Together, they work to understand more about the best ways to treat knee and kneecap problems in young people.
    • We track results of our patients so we can improve care and provide families with accurate information about our success rates, the risk of complications and the chance that patients will return to their previous level of activity. To help with this effort, we may ask you or your child to fill out questionnaires about their knee function after treatment.
    • Orthopedics and sports medicine care is about more than just the joints, muscles and bones. For example, we know that physical health and mental health can affect each other. We have done research on topics like depression symptoms in those with an ACL (knee ligament) injury so we can better address all of our patients’ needs.
    • Learn more about current orthopedics research at Seattle Children’s.

Symptoms of Knee and Kneecap Problems

Sudden swelling after an injury is a sign of trouble, as is pain.

Diagnosing Knee and Kneecap Problems

Kneecap tenderness. Courtesy of 'Fundamentals of Pediatric Orthopedics,' © 2003 Lippincott Williams & Wilkins

Point of maximum tenderness.

When you and your child visit our clinic, our doctors ask detailed questions about the pain your child is feeling and about any incidents or accidents that may have happened before the knee began to hurt. Then we examine your child’s knee.

  • Imaging tests your child may need

    We will probably take X-rays. We may also take pictures of your child’s legs as they stand still. This will help us spot any tendency in your child toward knock-knees, a condition that makes pain more likely.

    If we need more information, we may ask your child to have an:

    • MRI (magnetic resonance imaging) scan
    • CT (computed tomography) scan 

    These imaging tests make pictures that can help doctors:

    • See whether there is damage to the cartilage inside the knee.
    • Get a better look at the position of the kneecap.

Treating Knee and Kneecap Problems

We tailor treatment to help your child’s specific problem. For most cases of kneecap pain, we emphasize PT, including sports PT, and home exercise programs.

Seattle Children’s has physical therapists and facilities especially for children and teens. If your child needs surgery, we have pediatric orthopedic surgeons with the training and experience to repair children’s knee problems.

  • Physical therapy and exercise

    Physical therapy and home exercise programs strengthen muscles around the knee so that the kneecap stays in place.

    Exercises to strengthen the muscle on the inside of the front of the thigh (medial quadriceps) are especially important to treating kneecap problems successfully. When this muscle is strong, it helps keep the kneecap tracking correctly.

  • Surgery for knee and kneecap problems

    Children may benefit from surgery to help line up their knees and lower legs if:

    • They are severely knock-kneed.
    • Their kneecaps tend to slide out of joint (dislocate).

    There are a number of surgical approaches to treating kneecaps that tend to dislocate:

    • For children who are knock-kneed, temporary staples in the growth plate at the inside of the lower end of the thighbone can correct the problem. This procedure lets the outer growth plates grow while pinching the inner growth plates. This tends to straighten the legs over time and improve the kneecap’s tracking.
    • Older children may benefit from an operation that ties the kneecap down to the inner side of the knee. This keeps it from sliding to the side.
    • Another option is to move the attachment of the kneecap to the shinbone so that the kneecap tracks better.

    Surgery also may be the best treatment if your child has dislocated their kneecap and injured the cartilage covering the joint.

    In this operation, the doctor tries to reattach cartilage and bone where the dislocating kneecap has knocked them out of place. This is usually a minimally invasive procedure called arthroscopic surgery (PDF). It is done with small instruments inserted through smaller cuts than traditional techniques.

Contact Us

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

Providers, see how to refer a patient.