Sinding Larsen Johansson Syndrome

Sinding Larsen Johansson Syndrome


Article by J.Miller, Z.Russell, A.Clarke

What is Sinding Larsen Johansson Syndrome?

Sinding Larsen Johansson Syndrome is juvenile osteochondrosis that disturbs the patella tendon attachment to the inferior pole of the patella.

Sinding Larsen Johansson syndrome is an inflammation of the bone at the bottom of the patella (kneecap), where the tendon from the shin bone (tibia) attaches. It is an overuse knee injury rather than a traumatic injury.

What Causes Sinding Larsen Johansson Syndrome?

In the skeletally immature or adolescent athlete, Sinding-Larsen-Johansson syndrome most likely results from a traction injury of the knee extensor mechanism at the junction of the patellar ligament and the inferior pole of the patella. This juvenile traction osteochondrosis is similar to Osgood-Schlatter syndrome.

Strong repetitive quadriceps contractions are thought to cause a traction force on the inferior pole, disrupting the immature bone. There is a higher incidence in active children during the adolescent growth spurt.

As a child grows, bones go through different stages of development.

  1. The patella pole is initially cartilaginous (cartilaginous stage).
  2. It then enters the apophyseal stage when the secondary ossification centre (apophysis) appears.
  3. The unity of the proximal tibial epiphysis with the tibial apophysis marks the epiphyseal stage.
  4. Lastly, when the growth plates fuse, the bony stage has been reached.

Children are most susceptible to Sinding-Larsen-Johansson syndrome when their bones are in the (2nd) apophyseal stage. During this phase, the apophysis is unable to withstand high tensile forces. When presented with strong, repetitive muscle contractions, micro-fractures occur in the immature area.

A potential cause of Sinding-Larsen-Johansson syndrome may be the lack of growth of the quadriceps in comparison to the femur. During a growth spurt in a child, the lengthening of the muscle is unable to keep up with the lengthening of the rapidly lengthening femur, resulting in an increased tensile force on the patella.

Sinding-Larsen-Johansson Syndrome is more likely in very active children who participate in sports that involve running, twisting, and jumping, such as basketball, football, volleyball, soccer, tennis, figure skating, and gymnastics.

What the Symptoms of Sinding Larsen Johansson Syndrome?

Localised pain, swelling or tenderness is felt at the front of your knee – at the base of your patella (kneecap), where the patella tendon inserts into the patella.

Patients are typically active boys aged 10 to 13 years but can also affect active girls a couple of years younger. Symptoms are usually:

  • Worse with exercise, stair climbing, squatting, kneeling, jumping and running.
  • Cause you to limp after exercise (as the condition progresses).
  • May be unilateral or bilateral.
  • Is relieved by rest

What is the Symptom Progression?

While a mild case of Sinding Larsen Johansson syndrome can resolve within a few weeks, severe cases must be professionally managed to avoid growth plate damage. The pain and swelling symptoms can potentially last for years. Longstanding Sinding-Larsen-Johansson syndrome can result in an avulsion fracture of the patella tendon, which can severely affect your ability to walk or run.

Fortunately, Sinding Larsen Johansson Syndrome is very successfully managed via physiotherapy.

How is Sinding Larsen Johansson Syndrome Diagnosed?

Sinding Larsen Johansson Syndrome is normally diagnosed clinically by your physiotherapist or doctor. Knee X-ray can show calcification or ossification at the junction between the patella and the patella ligament. MRI scan will exclude most other musculoskeletal injuries.

Treatment for Sinding Larsen Johansson Syndrome

Physiotherapy assessment and treatment is a proven benefit for Sinding-Larsen-Johansson syndrome sufferers. Left untreated most patients will fully resolve their symptoms within 3 to 18 months (Duri et al 2002). With the good management, most athletes will be able to return to their sport within 6 to 14 weeks (Iwamoto et al 2009).

Phase 1 – Knee Load Management

  • Immediate restriction of high impact activities such as jumping and running.
  • Low impact activities eg. cycling, cross-trainer, water running or swimming are usually fine.
  • Use an infrapatellar knee strap to dissipate forces away from the site of Sinding-Larsen-Johansson syndrome. (Duri et al., 2002) An example of a Sinding-Larsen-Johansson syndrome brace can be found at this link:
  • Kinesiology taping may provide both pain relief and load reduction at the site of pain and injury.
  • Only on rare occasions, severe Sinding-Larsen-Johansson syndrome may require crutches.

Consult with your physiotherapist for the best advice specific to your knee.

Phase 2 – Anti-inflammatory Treatment

Ice & Electrotherapy

A combination of ice treatment, electrotherapy and a home tens unit will reduce pain and improve the healing rate. This usually hastens the recovery rate of sufferers. Ice is useful at home or after exercise. (Michlovitz et al 2007)

Phase 3 – Functional Training

Rest is also important in the management of Sinding-Larsen-Johansson syndrome and relief of pain. It is best to discuss your exercise workload with your physiotherapist for advice on how to best manage your return sport while respecting your injury.

Whether or not you should continue playing sport is dependent on symptoms. Patients with mild symptoms may be able to continue to play some or all sport. Others may choose to modify their program. In mild cases, it may enough to just limit your physical activity so that the post-exercise pain is only mild and lasts for a maximum of 24-hrs. When symptoms become worse it may be necessary to take a short break from your aggravating sports.

Phase 4 – Therapeutic Exercises

Stretching, Massage & Foam Rollers

One of the common reasons for developing Sinding-Larsen-Johansson syndrome is excessively tight quadriceps muscles, ITB, hamstrings, hip flexors and calf muscles. (Iwamoto et al 2009). Your physiotherapist will prescribe specific stretches for you if they assess that you are tight in these muscle groups.

Massage and foam rollers are beneficial especially in the early phase when stretches create pain at the Sinding-Larsen-Johansson syndrome site.


Your muscle control around the knee will usually need to be addressed to control or maintain your symptoms during the active phase of Sinding-Larsen-Johansson syndrome. Your physiotherapist will commonly prescribe or modify exercises for your quadriceps, hamstrings, calves, foot arch and gluteal (buttock) muscles. (Franchesci et al 2007)

Foot Arch Control & Orthotics

Your foot biomechanics or arch control may be inadequate for your intensity of the sport. Your physiotherapist can assist both the assessment and corrective exercises for your dynamic foot control. Active Foot Correction Exercises can be beneficial as both a preventative and corrective strategy. More information can be found here:

Occasionally, your foot biomechanics may be predisposing you to torsional stresses that can cause abnormal knee forces, which can cause knee injury. In these instances, foot orthotics may need to be prescribed. There are mixed views on how effective these are since the foot structure is rapidly changing at this age. Ask your physiotherapist or podiatrist for advice.

Prognosis for Sinding Larsen Johansson Syndrome

Sinding-Larsen-Johansson syndrome is a self-limiting syndrome. Complete recovery can be expected with the closure of the patella growth plate. Although symptoms of Sinding-Larsen-Johansson syndrome may linger for months, few patients have poor outcomes with conservative treatment, and surgical intervention is seldom necessary. Corticosteroid injections are not recommended due to case reports of subcutaneous atrophy.

Common Causes - Knee Pain

Knee pain can have many origins from local injury, referred pain, biomechanical issues and systemic issues. While knee pain can appear simple to the untrained eye, a thorough assessment is often required to ascertain the origin of your symptoms. The good news is that once a definitive diagnosis is determined, most knee pain quickly resolves with the correct treatment and rehabilitation.

Knee Ligament Injuries

Knee Meniscus Injuries

Kneecap Pain

Knee Arthritis

Knee Tendon Injuries

Muscle Injuries

Knee Bursitis

Children’s Knee Conditions

Other Knee-Related Conditions

Knee Surgery

For specific information regarding your knee pain, please seek the assistance of a healthcare professional with a particular interest in knee condition, such as your physiotherapist.

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