What Is Sinding Larsen Johansson Syndrome?
Sinding-Larsen-Johansson (SLJ) syndrome refers to the pain experienced at the bottom of the patella (kneecap) caused due to swelling and irritation of the local growth plate. SLJ syndrome is juvenile osteochondrosis (a joint disorder of growing children) and traction epiphysitis (injury to the cartilage and bony attachments) that affects the extensor mechanism of the knee, which degrades the patella tendon attachment to the patella. Pertaining to its nature, the syndrome is seen in pre-teens or growing individuals, irrespective of sex. The growth plate is composed of cartilage (present at the ebb of a bone) and is weaker and at risk for injury. According to some researchers, SLJ syndrome is closely associated with or similar to Osgood-Schlatter disease and jumper's knee.
Who Is Susceptible to Sinding Larsen Johansson Syndrome?
Although similar to jumper’s knee, which can occur at any age, SLJ syndrome is mostly seen in active-growing adolescents, primarily between the ages of 10 and 14. Individuals with preexisting cerebral palsy are more susceptible to developing SLJ syndrome. It mostly affects children between the aforementioned ages who are involved in sports or are very active.
What Causes Sinding Larsen Johansson Syndrome?
SLJ syndrome is basically caused by repeated stress on the kneecap growth plate. It is caused by increased traction on the patellar ligament, which causes inflammation at the site of insertion of the proximal ligament into the inferior pole of the knee cap (patella). SLJ syndrome causes the failure of the extensor mechanism of the knee. The extensor mechanism comprises quadriceps tendons, muscles, patella, patellar ligament, and the supporting retinaculum (deep fascia around and supporting the tendon). Any trauma, overuse, or degenerative disease of any of the components of the extensor mechanism can lead to SLJ syndrome, for example., Osgood-Schlatter disease affects the distal pole of the patellar tendon and tibial tubercle. Weak or tight thigh muscles or improper training techniques can also precipitate SLJ syndrome symptoms.
What Are the Types of Sinding Larsen Johansson Syndrome?
Medlar and Lyne studied the knee radiographs of SLJ patients to classify the syndrome. The suggested classification is as follows:
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Stage I: Normal appearance of the patella.
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Stage II: Distal pole of the patellar tendon has irregular calcifications.
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Stage III: Coalescing of the calcifications.
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Stage IVa: Coalesced calcification is concentrated at the distal pole.
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Stage IVb: Calcified ossicle is distinct from the distal pole.
What Are the Clinical Features of Sinding Larsen Johansson Syndrome?
Typically, patients with SLJ syndrome complain of tenderness near the bottom of the kneecap. On eliciting the history, the patient may provide a report of:
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Swelling near the kneecap.
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Tenderness near the kneecap.
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Pain increases with exercise or activities like running, climbing stairs, or jumping.
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Pain gets more severe when kneeling or squatting.
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Swollen or bony prominence at the bottom of the kneecap.
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Pain after sitting for a prolonged time with the knees flexed.
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Limping after physical activities.
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Unilateral or bilateral involvement.
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Kneeling becomes painful.
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Tightness of the thigh muscles (quadriceps).
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Fluctuating levels of pain.
How to Diagnose Sinding Larsen Johansson Syndrome?
The first sign of establishing a differential is to make a note of the site, onset, severity, and history of the pain. Flexing the knee and marking the range of motion of the joint is essential. Some of the diagnostic tests include
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Patellar grind test.
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Compression test.
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Extension resistance test.
Additional imaging studies provide supplemental evidence for an astute diagnosis.
1. Plain Radiographs:
Early findings are very subtle or nearly absent. Eventually, the thickening of the proximal patellar tendon, stranding of the Hoffa’s fat pad, and dystrophic calcification may be marked on the X-rays.
2. Ultrasound:
The images show thickening of the proximal patellar tendon, especially the posterior fibers that attach to the patella and focal zones of hypoechogenicity that are evidence of small tears.
3. Magnetic Resonance Imaging:
MRI is a great diagnostic tool for injury assessment. SLJ patients may show thickening of the proximal and posterior parts of the patellar tendon. Injuries at the inferior pole of the patella and in the adjacent fat can also be detected by the MRI.
How to Treat Sinding Larsen Johansson Syndrome?
First, RICE should be followed for primary relief. RICE stands for rest, ice, compression, and elevation. Activity modification is needed to ease off the pain, and avoiding high-impact exercises till the pain goes away is recommended. Low-impact exercises like cycling and swimming can be good alternatives to take the edge off the pain without sacrificing muscle strength and stamina. Once the pain settles down, it is advised to slowly build up high-impact sports participation with properly planned pre and post-exercise and sports regimes. Icing the area for 10 to 14 minutes post-activities can be beneficial.
Stretching exercises can be implemented with proper physiotherapy guidance. Some of the stretches to include in the daily regime are lower limb stretches, quadriceps stretch, hamstring stretch, and stretch two. These stretches can be repeated in sets. Wearing shock-absorbing insoles in the shoes can help aid recovery.
Pharmacotherapeutic protocols can be implemented for short-term pain relief. These include NSAIDs (non-steroidal anti-inflammatory drugs) and OTC (over-the-counter) drugs. NSAIDs should not be taken more than ten days without re-consulting.
By following the instructions diligently, the patient can completely recover without any secondary disability. SLJ is a temporary condition. Although the tendons take time to heal, the patient is expected to have a complete recovery.
What Is the Complication of Sinding Larsen Johansson Syndrome?
Several complications may arise either from the condition or its treatment. Some of the complications include
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Bleeding.
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Bowel complications.
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Complete separation or fracture of the growth center.
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Recurrence of the condition in adulthood.
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Symptomatic bone fragments below the affected knee.
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Persisting prominence.
What Is the Differential Diagnosis of Sinding Larsen Johansson Syndrome?
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Osgood-Schlatter disease (pain and swelling below the knee joint).
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Jumper’s knee (inflammation of the patellar tendon).
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Patellar sleeve fractures (separation of cartilage from the ossified patella).
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Bipartite patella (patella is made up of two bones instead of one).
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Infrapatellar bursitis (inflammation and swelling within the bursa of the infrapatellar patella).
Conclusion
Sinding-Larsen-Johansson syndrome is a temporary painful event in growing teens and is not a worrisome incident. With easy enough management protocols, the syndrome goes into remission. Sportspersons may get impatient and opt for a cortisone injection to the knee joint. Although it gives immediate relief, it makes the tendons weaker. So it is better to hold on and let the body do its healing.
