A spectrum of entities is involved in injury to the inferior aspect of the patella and the proximal patella tendon, including Sinding-Larsen- Johansson syndrome, patellar sleeve avulsion and jumper’s knee. The patellar tendon is usually only a few centimetres long, arising from the inferior patella and inserting distally into the tibial tuberosity. Sinding-Larsen-Johansson syndrome is an osteochondrosis of the inferior pole of the patella and is often bilateral. It is not osteonecrosis, epiphysitis or osteochondritis as previously described in the literature. Sinding- Larsen-Johansson is commonly seen in active adolescents aged between 10 and 14 years, as described in our patient. Our case highlights the importance of an adequate history, clinical examination combined with correct imaging in accurate, early diagnosis of Sinding-Larsen- Johansson syndrome, a rare but important course of patellofemoral pain.