SINDING-LARSEN–JOHANSSON DISEASE
Sinding-Larsen–Johansson disease is another common cause of anterior knee pain in children and adolescents. It is similar to Osgood-Schlatter disease, except that Sinding-Larsen–Johansson disease occurs at the inferior pole of the patella. Affected patients are between 10 and 13 years of age and are often involved in athletic activities.16 Symptoms are aggravated by jumping or direct pressure over the inferior pole of the patella. Point tenderness is localized to the inferior pole of the patella. Although it is diagnosed clinically, radiographs should be obtained to rule out other pathology. Radiographs may show soft-tissue swelling and calcification of an avulsed portion of the patella.
Sinding-Larsen–Johansson disease is a self-limited process that responds to activity modification and acetaminophen or NSAIDs. Knee immobilization is only necessary in severe cases. Exercises to improve flexibility of the hamstrings, quadriceps, and heel cords can help reduce symptoms.17Symptoms usually resolve within 10 to 12 months, and the condition is rare after skeletal maturity.18