The patient is exhibiting signs of hemophilia. Hemophilia A is the most common type of hemophilia, and it is caused by a factor VIII deficiency. Factor VIII concentrate is the treatment of choice for hemarthrosis. Although DDAVP can be used to increase Factor VIII levels in mild disease, the patient requires Factor VIII replacement for severe disease. Celecoxib is used to treat osteoarthritis, not hemarthrosis due to hemophilia A. Platelets may be necessary, but the patient likely has normal platelet level; hemophilia is characterized by a defect in the coagulation cascade.