Osgood-Schlatters Disease is a common cause of knee pain in late adolescent and early teenage boys. The condition is less prevalent in females, although being active in sports increases a young female’s chances. This condition was named for the two doctors who defined the condition, simultaneously, in 1908; Dr. Robert Osgood and Dr. Carl Schlatter.
The quadriceps tendon attaches to the patella (knee cap) and then continues down to the top of the tibia as the patellar tendon. When the quadriceps muscle flexes it shortens pulling upward on the tendon, which in turn causes the tendon to pull up on the tibia, causing the lower leg to extend. As with any attachment it is under considerable stress when forcibly extending the knee or supporting the bodyweight during dynamic activities. Repetitive forceful contractions of the quadriceps can cause tiny avulsion fractures at the tendon attachment on the tibia. The bone will attempt to repair itself by adding more calcium to the area to protect and strengthen the attachment. This causes the lump under the knee often associated with Osgood-Schlatters Disease. When an adolescent or young teen goes through a growth spurt the muscles often struggle to keep pace with the growing bones and therefore are often too short compared with the accompanying bones. This places additional stress on the attachments and happens often with the femur and quadriceps muscle. The femur grows quickly and the quadriceps does not stretch so the muscle is tight until it has a chance to adapt to the new growth. This puts a chronic strain on the quadriceps and patellar tendon. This stress leads to those tiny fractures at the attachment site when the muscle is under stress. These lead to the calcium loading at the site and pain and inflammation result.
Causes of Osgood-Schlatters
Osgood-Schlatters may be caused by any condition that puts extra stress on the patellar tendon resulting in small breaks at the attachment site. Some of the common causes:
- A growth spurt or rapid lengthening of the femur, causing the quadriceps to be tight.
- Repetitive stress to the patellar tendon through knee flexion and extension, such as with kicking or landing when jumping.
- Chronically tight quadriceps as seen with weight training without proper flexibility training as well.
- Untreated injury to the knee causing small avulsion fractures to the patellar tendon attachment on the tibia
Signs and Symptoms
Knee pain without an apparent direct cause or pain in the knee during and after exercise may be a sign of Osgood-Schlatters Disease. Although the symptoms may be similar to other conditions, such as patellar tendonitis, in younger athletes this condition should be considered. Some of the common signs and symptoms of this disorder include:
- Pain below the knee cap, worsens with exercise or when contracting the quadriceps.
- Swelling and tenderness below the knee.
- A bony prominence may be noted under the knee as the condition advances.
- A “grinding” or stretching sensation may be noted at the tendons attachment site.
Preventing Osgood-Schlatters Disease involves avoiding or changing the conditions that lead to it. Knowing that chronic stress on the tendon and attachment causes this disorder, it is important to reduce that stress. Some of the strategies for prevention include:
- Proper warm-up techniques will help prepare the muscles and tendons for the activity and increase the flexibility of the tendon. Warmer tendons are more flexible tendons.
- If particular activities cause pain they are probably causing stress on the area. Reducing or avoiding these activities will help prevent the development of this condition. It is important to distinguish between healthy muscle pain and pain of injury. If it is stiffness and pain in the belly of the muscle and goes away in 24 hours it is simply pain from muscle breakdown and recovery, if it does not go away in a day or two, or is focused around a joint or bone attachment it may be the result of an injury.
- Since a lot of the stress placed on the quadriceps and patellar tendons is due to tight quadriceps muscles, stretching these muscles to relieve the tightness and to lengthen the muscle will help alleviate some of the stress. Developing a balance between the hamstrings and quadriceps is also important. If the hamstrings are proportionately weaker than the quadriceps then they will not be able to act as a counter force against the forceful quadriceps contractions, which could put additional stress on the tendon. If the quadriceps muscles are weaker than the hamstrings (very rare) they will be chronically tight from resisting the hamstrings. Strengthening the quadriceps also helps facilitate muscle lengthening and increases flexibility if done properly through a full range of motion.
Exercises for Osgood Schlatters disease
The following exercises are commonly prescribed to patients with this condition. You should discuss the suitability of these exercises with your osteopath prior to beginning them. Generally, they should be performed 3 times daily and only provided they do not cause or increase symptoms.
Static Quadriceps Contraction
Begin this exercise by sitting with your leg straight in front of you (figure 2). Tighten the muscle at the front of your thigh (quadriceps) by pushing your knee down into a towel. Put your fingers on your inner quadriceps to feel the muscle tighten during contraction. Hold for 5 seconds and repeat 10 times as hard as possible pain free.
Begin this exercise by holding a chair or table for balance. Take your heel towards your bottom, keeping your knees together and your back straight until you feel a gentle stretch in the front of your thigh or as far as you can go without pain. Hold for 15 seconds and repeat 4 times at a mild to moderate stretch pain-free.