Flawless Physio Logo
Knee Pain

Sinding Larsen Johansson Syndrome

Minute Read


Posted 1 year ago


Last updated: 16/09/2023


by James McCormack

What is Sinding Larsen Johansson Syndrome?

Sinding Larsen Johansson Syndrome (SLJ) is a type of knee injury that causes pain and swelling in the bottom tip of the kneecap, typically occurring in children and teenagers, most commonly between the ages of 10 and 14, who are active in sports. 

Sinding Larsen Johansson Syndrome affects the growth plate, also known as an epiphyseal plate, near the bottom tip of the kneecap. This growth plate is responsible for the bone’s growth during childhood and adolescence.  Growth plates have two main areas: a proliferative zone containing cells that divide and multiply, creating new cartilage and a hypertrophic zone where the cartilage matures and eventually calcifies, turning into bone.

Sinding Larsen Johansson Syndrome occurs when tension is placed on this growth plate due to repetitive traction by the patellar tendon during running, jumping and impact sports.

Sinding Larsen Johansson Syndrome is often misdiagnosed as Patellar Tendonitis, which is in the exact location but in adults, or Osgood Schlaters, which causes pain and irritation lower down on the patellar tendon insertion to the tibial tuberosity.

Picture of Location of Sinding Larsen Johansson Syndrome Pain

Sinding-Larsen Johansson Syndrome Symptoms


  • Pain localised to the lower part of the kneecap is more intense or sharp during impact activities but eases with rest.
  • Swelling at the front of the kneecap, especially after sports
  • Pain when running, jumping, or walking upstairs
  • Pain when kneeling or squatting 
  • A patient may have a visible limp after exercise

Sinding-Larsen Johansson Syndrome Diagnosis

A healthcare professional such as a family doctor or physical therapist will ask about the symptoms and history of the development of this injury.

The clinician will then conduct a physical examination to assess where the pain is and if they can reproduce the symptoms with the common aggravating movements, such as stretching the quadriceps, squatting or jumping.

If there is any doubt over the diagnosis, a clinician may refer the patient for imaging:

Photo of Child with Sinding Larsen Johansson Syndrome

Radiology for Sinding-Larsen Johansson Syndrome

While radiology in not always necessary there are three forms of imaging can provide information for suspected Sinding Larsen Johansson syndrome:


While x-ray is the least sensitive form of imaging for Sinding Larsen Johansson syndrome, it will usually be able to rule out a fracture, or stress fracture, of the patella or shin bone, which might give similar symptoms.



An MRI of a suspected Sinding Larsen Johansson syndrome will show inflammation which can indicate the injury to the growth plate.



Ultrasound is the most informative, cost-effective and the least invasive imaging technique for Sinding Larsen Johansson syndrome. It can also be a less stressful assessment for a child as there is no need to lie still for long periods, and due to the lack of radiation the parent can be with them throughout. The scan can be done dynamically and explained by the healthcare professional as they move the knee and assess the area.


Child playing football after recovering from Sindig Larsen Johansson Syndrome

How Long Does Sindig-Larsen Johansson Syndrome Last?

Sinding Larsen Johansson syndrome typically persists until the child or teenager’s growth plates have closed, usually in the late teens.

However, with the appropriate management, the symptoms of Sinding Larsen Johansson syndrome can be alleviated while the child is still growing.

To manage Sinding Larsen Johansson syndrome symptoms, we recommend reducing impact activities, increasing the rest period between impact activities and trying alternative sports such as swimming or rowing.

Patients can ice their knee for 10-15 minutes, 3-4 times daily, for pain relief while they continue to exercise.

Generally, with activity modification, symptoms in mild cases can improve considerably in 6-8 weeks.

Relieving severe cases can take up to 16 weeks of activity modification. It is only in a few very rare cases complete immobilisation is required.

Physiotherapy with James McCormack

This is not medical advice. We recommend a consultation with a medical professional such as James McCormack. He offers Online Physiotherapy Appointments weekly.

Share this page