Parapatellar knee pain syndrome or chondromalacia patellae: children with this common condition usually have vague pain in both knees around the knee cap or patella. It is not known what causes the pain and x-rays and other testing will be normal. The pain is made worse by certain activities, such as running, jumping, doing knee bends, sitting for a long time, or climbing stairs and improves after a period of rest. Treatment consists of rest from any activity that regularly makes the pain worse, avoiding knee bend exercises (especially weight machines), and using an anti-inflammatory medicine such as ibuprofen. You can also do strengthening exercises, such as isometric quadriceps exercises and/or flexibility exercises.

Osgood Schlatters Disease: This is another very common condition that occurs most commonly in adolescents who are very active, especially in activities that require running, jumping, or weight lifting. Children with this disease will have a tender bump near the top of their tibia (a bone in their lower leg), just below the knee cap. Pain in this area usually occurs after certain activities, with kneeling or if the bump is directly touched or banged. There is no treatment, except to try and improve the symptoms. You can try an ace wrap or knee pad to protect the area from being touched. Restriction of activities is only necessary if the pain is too severe to play through. The pain will go away with time (1-2 years), as the bones complete their growth process.

Osteochondritis dissecans: this condition occurs because a fragment of bone forms for unknown reasons and can cause vague knee pain. Children can also have more severe pain, swelling of the knee, locking of the knee or it may cause the knee to give way. The diagnosis is made with an x-ray. While minor cases in younger children can be observed without treatment and may heal, in older children, or those with more severe symptoms, repair with arthroscopic surgery will probably be required.