The knee is a joint that joins the thigh bone (femur) to the top of the shin bone (tibia). It is made up of bones, cartilage, muscles, ligaments, and tendons. These parts work together to make the legs bend, straighten, and swivel. A knee injury can damage one or more parts of the knee.

In growing children, the patellar tendon attaches to the growth plate of the kneecap, and repetitive stress on the tendon can irritate and injure the growth plate. This condition is referred to as Sinding-Larsen-Johansson disease. It almost always affects children between the ages of 10 and 14 who play sports or are especially active. The age range is so specific because of how kids’ bodies grow and change. Between 10 and 14, the growth plate at the top of their shinbone is very active and vulnerable to injuries.

Jumper’s knee refers to pain that occurs in the lower portion of the kneecap (patella). These painful symptoms can range from mild to severe.

Repetitive contraction of the quadriceps muscles in the thigh can stress the patellar tendon where it attaches to the kneecap, causing inflammation and tissue damage (this condition is also known as patellar tendinitis).

Growth spurts when kids’ bones, muscles and tendons all rapidly change at the same time can put their knees under extra stress too.

The patellar tendon is like a thick rubber band that connects your kneecap to your shin. It holds the bones together and helps them move properly. Sinding-Larsen-Johansson syndrome is caused by repeated tension and pressure on the patellar tendon when kids squeeze their thigh muscles (quadriceps). The overuse that causes SLJ can be caused by any repetitive motion, including:

  • Running
  • Jumping
  • Kicking
  • Any activity or sport that makes kids repeatedly exert a lot of force with their legs and knees.

Another similar condition, known as Osgood-Schlatter disease shares many of the causes, symptoms and treatments. In fact, both conditions refer to injured patellar tendons in kids and teens. It can be hard to tell the difference between Sinding-Larsen-Johansson syndrome and Osgood-Schlatter disease, because they’re both caused by overuse – usually from playing sports. These happen when someone trains too much or makes repetitive motions involving the knee. Jumper’s knee refers to pain that occurs in the lower portion of the kneecap (patella). These painful symptoms can range from mild to severe.

The most common reason for knee pain in children is due to overuse. The anatomy of a child’s knee joint is extremely sensitive to small problems in alignment, training, and overuse. Pressure may pull the kneecap sideways out of its groove, causing pain around kneecap.

Jumper’s knee symptoms occur where the patellar tendon attaches to the patella.

Whether the problem stems from the tendon or growth plate, a child will need to rest from sports activities until the pain resolves.

In addition to rest, your doctor may recommend applying an ice pack to the knee every 2 to 3 hours for a few days until the pain starts to go away. Nonsteroidal anti-inflammatory medications may also help to relieve painful symptoms.

Like Osgood-Schlatter disease, jumper’s knee can result in a fracture if a child continues to participate in sports activity without adequate rest. A fracture at the lower end of the kneecap will require treatment with casting or surgery, depending upon the type of fracture. The recovery time for a fracture of the patella requires prolonged absence from sports.

This article ” Knee overuse injuries in children”  does not provide medical advice and is intended for informational purposes only. It is not a substitute for professional medical advice, diagnosis or treatment. Please consult a doctor for all medical advice.


Meet Dr Peter Smith, a leading Orthopaedic Surgeon operating from the Mediclinic Milnerton in Cape Town, Western Cape. His practice is situated in the heart of this seaside town.  Dr Peter Smith not only offers patients the full spectrum of professional orthopaedic treatments, but specialises in total knee replacement, total hip replacement, sports injuries and the latest arthroscopic surgery techniques and computer guided surgery. He gained extensive experience in the latest arthroplasty techniques during his stay of 6 years in Australia where he performed more than a hundred primary and revision hip and knee replacements cases in a year.

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