The Clinical Syndrome

Osgood-Schlatter disease is characterized by anterior knee pain that is exacerbated by stress on the quadriceps mechanism and by direct pressure on the tibial tuberosity. Although the disease can affect all ages, most cases occur in adolescents, with a peak incidence at approximately 13 years of age. Boys and men are affected two to three times more often than are girls and women, although some investigators believe that the number of female cases is on the rise as a result of increased female participation in competitive sports. The pain and functional disability associated with Osgood-Schlatter disease are bilateral in 25% to 30% of patients, and one side often has more severe symptoms. Osgood-Schlatter disease is usually the result of overuse or misuse of the knee joint caused by running, jumping, or overtraining on hard surfaces, as well as any other activities that require repetitive quadriceps contraction ( Fig. 116.1 ). Competitive sports most often implicated in the development of Osgood-Schlatter disease include soccer, gymnastics, basketball, ballet, track, hockey, baseball, and Irish and Scottish Highland–style dancing ( Box 116.1 ).

Osgood Schlatter disease.

(From Macnicol MF. Paediatric knee problems. Orthop Trauma. 2010;24(5):369–380.)

The quadriceps tendon is made up of fibers from the four muscles that constitute the quadriceps muscle: vastus lateralis, vastus intermedius, vastus medialis, and rectus femoris. These muscles are the primary extensors of the lower extremity at the knee. The tendons of these muscles converge and unite to form a single, exceedingly strong tendon. The patella functions as a sesamoid bone within the quadriceps tendon, with fibers of the tendon expanding around the patella and forming the medial and lateral patella retinacula, which strengthen the knee joint. The patellar tendon extends from the patella to the tibial tuberosity. The tibial tuberosity is the nidus of the pain and functional disability associated with Osgood-Schlatter disease because the repetitive stresses applied to the tibial tuberosity by contraction of the quadriceps mechanism result in apophysitis and heterotopic bone growth. These responses to the damage induced by repetitive stress are most often seen during the period of rapid skeletal growth associated with adolescence, although as mentioned earlier, this disease has been reported in all age groups.

Signs and Symptoms

Patients with Osgood-Schlatter disease present with pain over the anterior knee and with pressure on the tibial tuberosity. Patients note increased pain on walking down slopes or up and down stairs, as well as during any activity that involves contraction of the quadriceps mechanism. Activity using the knee makes the pain worse, whereas rest and heat provide some relief. The pain is constant and is characterized as aching; it may interfere with sleep. On physical examination, the patient notes significant pain on palpation of the tibial tuberosity, as well as tenderness to palpation of the patellar tendon. Enlargement of the tibial tuberosity is often readily apparent, and this cosmetic defect can cause significant anxiety in the patient and parents. Generalized swelling of the joint may be present, and thickening of the patellar tendon may be appreciated on careful physical examination. Active resisted extension of the knee reproduces the pain, as does pressure on the tibial tuberosity. Coexistent suprapatellar and infrapatellar bursitis, tendinitis, arthritis, or internal derangement of the knee may confuse the clinical picture after trauma to the knee.