Osgood-Schlatter disease (Knee pain, Apophysitis of the tibial tubercle) is an inflammation of the upper part of the tibia, the most common reason of the knee pain among the physically active children and young adults.
Osgood-Schlatter disease is the most common cause of the knee pain in adolescents who are involved in sporting activities such as football, volleyball, basketball and gymnastics. The age of affected children is typically between 12 and 15 years for boys and between 8 and 12 years for girls, although the condition is more usual for boys. In 30% of cases, both knees are affected.
Children experience knee pain during working out that relieves after resting.
The onset of the disease takes place before the tibial tuberosity (a large oblong elevation on the proximal, anterior aspect of the tibia, where the patellar ligament attaches) has finished ossification. The patellar ligament is the distal portion of the common tendon of the quadriceps femoris (a muscle in the front of the thigh).
If the child is regularly running and jumping the strength of the quadriceps prevails over the ability of the tibial tuberosity to withstand it. The force of the contractions leads to multiple small avulsion fractions of quadriceps at the site of the attachment to the shinbone. After the fractions have healed, they lead to the enlargement of tibial apophysis and developing of a bony bump. This is the so-called overuse mechanism of the damage to the knee.
Sometimes the disease occurs without any apparent cause, probably due to the different development of the bones at their ossification sites and the growing muscle strength especially during so-called growth spurts.
Types of avulsion fractures
Avulsion fraction is a type of bone fracture when a bone fragment is separated from the bone in the result of physical trauma. In Osgood-Schlatter disease this means that tibial tuberosity is torn away from the shinbone.
Type I: A small fragment is displaced proximally; does not require surgery.
Type II: The articular surface of the tibia is intact; the fracture occurs at the junction where the secondary center of ossification and the proximal tibial epiphysis are joined. Surgery may be needed or not;
Type III: Complete fracture with high chance of meniscal damage. Usually requires surgery.
Related: Acute knee pain
Children who work out regularly (running and jumping) and are at the age between 8 and 15 are at risk of experiencing knee pain.
The most traumatic sports for children include: basketball, volleyball, soccer, long-distance running, gymnastics and figure skating.
Symptoms of Osgood-Schlatter disease develop gradually. At the beginning of the disease development a child complains of the knee pain that occur during physical activities such as running, jumping, squatting, and ascending or descending stairs.
Over the tibial tubercle a firm mass may be palpable, the tibia is swollen, red, warm and tender to the touch, the area of the tibial apophysis is enlarged, the quadriceps atrophies and becomes tight.
The pain occurs or worsens by direct pressure and jumping or with resisted knee extension.
Diagnosis is based on the typical complains, medical history and the results of the examination.
On X-ray of the leg soft tissue swelling with the loss of the sharp margins of the patellar tendon is visible in the acute phase. Bone fractures may be seen 3 weeks after the onset.
Ultrasound imaging shows swelling of the cartilage and surrounding tissues, infrapatellar bursitis, fragmentation and instability of the ossification center.
Knee pain vanishes usually by itself when the child’s bones stop growing.
Children should avoid sports in the acute phase of the disease and can continue when the pain is gone. During that time children are encouraged to work out other sports such as swimming. However, in severe cases the child should stop training at all.
To relieve the pain a child may use RICE therapy:
R – Rest the knee from the painful activity;
I – Ice over the affected area for 20 minutes every 2-4 hours;
C – Compress the painful area with an elastic bandage;
E – Elevate the leg.
Analgetics and non-steroidal anti-inflammatory drugs (NSAIDs) are used to alleviate the pain and reduce the swelling.
As physical therapy during the recovery phase straight leg raises, short-arc quadriceps exercises and wall slides can be performed. Recommended efforts include exercises to improve the strength of the quadriceps, hamstring and gastrocnemius muscles.
Surgery is indicated in rare cases, as it is even harmful to operate on the immature skeleton.