Sinding-Larsen-Johansson syndrome

History and clinical findings A 12-year-old boy presented to a paediatric rheumatology clinic with a 2-month history of painful knees. He had been referred from the paediatric oncology department with a previous diagnosis of acute lymphocytic leukaemia, in remission for 5 years. The pain was felt just below the patella, especially after a game of soccer, climbing stairs or walking for long distances. There was associated swelling of both knees, but no early-morning stiffness or deformities were described. Clinical examination revealed bilateral mild knee effusions with tenderness over the infrapatellar area in the region of the infrapatellar ligament. A prominence of the infrapatellar area was noted during flexion of the knee. The child was unable to assume a kneeling position due to pain over the knees. No ligamentous or meniscal instability was noted. There was no evidence of synovitis of any of the joints or evidence of an inflammatory arthropathy.