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Osgood-Schlatter disease (traction apophysitis)



Musculoskeletal system


Pediatric musculoskeletal conditions
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Osgood-Schlatter disease (traction apophysitis)


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High Yield Notes
16 pages

Osgood-Schlatter disease (traction apophysitis)

8 flashcards

USMLE® Step 1 style questions USMLE

1 questions

A 14-year-old boy is brought to his primary pediatrician for evaluation of left knee pain. He plays basketball for his high school team, and the pain started four weeks following the start of the season. The pain is worsened with running and jumping and relieved with rest. He has no significant past medical history. Vitals are within normal limits. He is at the 75th percentile for height and 40th percentile for weight. Physical examination reveals anterior knee pain located at the position of the arrow, as seen in the image below. Which of the following best describes the etiology of this patient’s condition?

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External References

Content Reviewers:

Rishi Desai, MD, MPH

Osgood-Schlatter disease is an inflammation of the patellar ligament, right at the point where it inserts on the tibial tuberosity, resulting in painful swelling just below the knee.

It’s named after two orthopedic surgeons; the American Robert Osgood, and the Swiss Carl Schlatter.

So focusing in on the knee, the proximal epiphysis of the tibia, which is the upper end of the tibia that contributes to the knee joint, has a bony prominence called the tibial tuberosity.

This is considered an apophysis, meaning that it’s a bony prominence that serves as a site for tendon attachment.

The tibial tuberosity specifically serves as the attachment site for the patellar ligament, which is an extension of the quadriceps muscle tendon.

When the patellar ligament contracts, it extends the knee.

At birth, the proximal epiphysis consists of cartilage, but it contains an ossification center inside.

This ossification center begins to ossify or turn to bone between the ages of nine and fifteen, and becomes a bony tuberosity around the age of eighteen.

Osgood-Schlatter disease typically develops between the ages of nine and fifteen years old when the tuberosity hasn’t ossified yet, and therefore isn’t hard enough to resist traction of the patellar ligament.

So, this is why the disease is very common in young adolescents who play sports requiring the quadriceps muscles to contract repetitively, causing the patellar ligament to excessively strain on the not-yet-ossified tibial tuberosity.

This results in inflammation of the ligament at the point it inserts to the tuberosity, what is known as traction apophysitis.


Osgood-Schlatter disease is a common condition that affects the knee in adolescents, typically during the growth spurt that occurs just before puberty. It is caused by repetitive traction of the patella ligament on the tibial tuberosity, causing it to become inflamed, which results in a painful swelling just under the knee.

People with Osgood-Schlatter disease with a palpable lump below the knee, which gets very painful with physical activities like running, jumping, squatting, and especially when going up or down stairs, or when the knee gets hit by something. The treatment consists of reducing physical activity and applying ice to the tuberosity to reduce swelling, as well as pain medication. Rarely, surgery may be necessary, especially if fragmented bones have avulsed off, and get trapped within the patella ligament.

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