the tuberosity and producing a visible lump which can be very painful, especially when hit. Activities such as kneeling may also irritate the tendon. The syndrome may develop without trauma or other apparent cause; however, some studies report up to 50% of patients relate a history of precipitating trauma. Several authors have tried to identify the actual underlying etiology and risk factors that predispose Osgood–Schlatter disease and postulated various theories. However, currently, it is widely accepted that Osgood–Schlatter disease is a traction apophysitis of the proximal tibial tubercle at the insertion of the patellar tendon caused by repetitive micro-trauma. In other words, Osgood–Schlatter disease is an overuse injury and closely related to the physical activity of the child. It was shown that children who actively participate in sports are affected more frequently as compared with non-participants. In a retrospective study of adolescents, old athletes actively participating in sports showed a frequency of 21% reporting the syndrome compared with only 4.5% of age-matched nonathletic controls. The symptoms usually resolve with treatment but may recur for 12–24 months before complete resolution at skeletal maturity, when the tibial epiphysis fuses. In some cases the symptoms do not resolve until the patient is fully grown. In approximately 10% of patients the symptoms continue unabated into adulthood, despite all conservative measures. Long-term implications OSD occurs from the combined effects of tibial tuberosity immaturity and quadriceps tightness. There is a possibility of migration of the ossicle or fragmentation in Osgood-Schlatter patients. The implications of OSD and the ossification of the tubercle can lead to functional limitations and pain for patients into adulthood. Of people admitted with OSD, about half were children who were between the ages of 1 and 17. In addition, in 2014, a case study of 261 patients was observed over 12 to 24 months. 237 of these people responded well to sport restriction and non-steroid anti-inflammatory agents, which resulted in recovery to normal athletic activity. Epidemiology Osgood–Schlatter disease generally occurs in boys and girls aged 9–16 coinciding with periods of growth spurts. It occurs more frequently in boys than in girls, with reports of a male-to-female ratio ranging from 3:1 to as high as 7:1. It has been suggested that difference is related to a greater participation by boys in sports and risk activities than by girls. Osgood Schlatter's disease resolves or becomes asymptomatic in the majority of cases. One study showed that