IS case 448: Sinding-Larsen-Johansson syndrome
Imaging Sciences URMC 2010
Publication Date: 2010-08-30
Plain AP and lateral radiographs of the right knee demonstrated a shallow trochlea space with small patellar osteophytes and elongation of the caudal portion of the patella. No cortical disturbance, trabecular irregularity, dislocation or joint effusion was present.
Sinding-Larsen-Johansson (SLJ) syndrome (a.k.a. distal patellar apophysitis or "jumper's knee") is irritation and inflammation of the growth plate of the inferior patella, at the location of the patellar tendon insertion. SLJ is most often seen in children between the ages of 10 and 15 and usually appears during a period of rapid growth. It is typically caused by increased tension and pressure on the growth center from overuse injury such repetitive running and jumping.
X-rays may show irregular bone edges or fragments at the inferior patella as in this case, but are not always required to make the diagnosis. Four roentgenographic stages of the disease process have been previously described: Stage 1, normal findings; Stage 2, irregular calcifications at the inferior pole of the patella; Stage 3, coalescence of the calcification; Stage 4, incorporation of the calcification into inferior patella.
Treatment involves resting from painful activities in order to take pressure off the growth center and allow the inflammation to resolve. Ice packs, supportive knee straps, and stretching exercises are also recommended.
- Medlar RC, Lyne ED. Sinding-Larsen-Johansson disease. Its etiology and natural history. J Bone Joint Surg Am. 1978 Dec;60(8):1113-6. PMID: 721864
- Greenspan A. Orthopedic Imaging: A Practical Approach, 4th ed. Lippincott Williams & Wilkins, 2004: 664.