What is Sinding-Larsen-Johansson Syndrome?
Sinding-Larsen-Johansson Syndrome, or inferior patellar epiphysitis, is a relatively common cause of chronic knee pain in young adolescents. It classically affects very active 10-13 year olds participating in jumping sports, and is considered an overuse injury. Medically it caused by inflammation at the attachment site of the patellar tendon on the bottom of the knee cap. (See figure below)
What are the symptoms of Sinding-Larsen-Johansson Syndrome?
- The most common symptom is knee pain with or without swelling, and is common to see at the same time in both knees. The pain is typically at the bottom of the kneecap and is worsened by activity.
- Atypical symptoms may include pain at night and redness
How is it diagnosed?
- This is typically a clinical diagnosis, meaning that can be made with a thorough history and physical. Sometimes in the setting of more chronic pain that isn’t improving with appropriate treatment, imaging will be performed such as ultrasound, x-rays, and/or MRI to rule out other pathology. (See below for other conditions that may at first present like Sinding-Larsen-Johansson Syndrome.) MRI is typically reserved for someone with atypical symptoms.
How is it treated?
- Along with most overuse injuries, treatment is typically conservative with rest, ice, over-the-counter pain medications. Topical anti-inflammatory can be very helpful due to the superficial location of the pain and inflammation. A very safe over the counter, all-natural anti-inflammatory that can be used is arnica, and can be found at any pharmacy, or even on the shelf at Whole Foods or Sprout’s. Modifying activity by stopping motions that cause pain is helpful. Formal or home physical therapy is also helpful with a focus on stretching and strengthening exercises. Naturally the quadriceps muscle needs to be stretched, but even more important is the need to stretch the hamstrings. Since the quad muscle straightens the knee and the hamstrings bend the knee, if the hamstrings are very tight, which is common in rapidly growing and active adolescents, then the quad must work harder when jumping and running and the knee is extended/straightened.
How can it be prevented?
- Adequate stretching with careful attention on flexibility of the hamstrings and quadriceps is very helpful. Proper strengthening of the quadriceps, gluteal muscles and core are also key to preventing this condition.
What are the long-term outcomes?
- With conservative management Sinding-Larsen-Johansson Syndrome tends to self-resolve within several weeks. This can be a recurring problem that seems to come back a few times during the peak age ranges, during periods of rapid growth and increased physical activity.
If it’s not Sinding-Larsen-Johansson Syndrome, then what else could it be? (What else are we looking for with ultrasound, x-rays or MRI?)
- Patellar tendinitis (inflammation of the patellar tendon), or even a partial tendon tear from the knee cap
- Patellofemoral stress syndrome (inflammation and irritation of the knee cap)
- Chondromalacia patella (inflammation and sometimes damage of the cartilage on the back of the knee cap)
- Osgood-Schlatter’s Disease (inflammation and irritation of the top of the shin bone, or tibia, where the patellar tendon attaches)
- Impingement of Hoffa’s anterior fat pad of the knee (inflammation and swelling of the fat pad that is just deep to the patellar tendon)
- Pre-patellar bursitis (inflammation in the soft tissues, typically with fluid collection/swelling just over the knee cap)
By Brad Watts, D.O. PGY-2 and Jon Minor
Bibliography
Valentino M, Quiligotti C, Ruggirello M. Sinding-Larsen-Johansson syndrome: A case report. Journal of Ultrasound. 2012;15(2):127-129. doi:10.1016/j.jus.2012.03.001.
