Osgood-Schlatter Disease
Osgood-Schlatter disease is an overuse injury of the knee that occurs during growth. It's caused by continuous pulling of the patellar tendon on the developing tibial tuberosity, a bony prominence just below the kneecap. The condition is most common in boys aged 10 to 15 and girls aged 8 to 13, and occurs more often in boys than in girls.
Symptoms
Symptoms include a warm, somewhat swollen and painful lump below the knee. Cycling, climbing stairs, starting, stopping, sprinting, jumping, deep knee bends and kneeling are usually painful. In tennis players, symptoms tend to occur during low volleys, side-to-side drills and serving. Symptoms can develop either suddenly or gradually, and often come and go.
The injury is linked to growth. The cartilage at the growth plate of the tibial tuberosity (the bump just below the knee) can tolerate less load than bone. Once the growth plate has closed and all the cartilage has converted into bone, the symptoms disappear for good. In most cases, though, symptoms have already resolved before that point. On average the condition lasts about six months, though some young athletes have symptoms for only a few months while others experience them for up to two years. In rare cases a person still has symptoms after reaching adulthood; this is usually due to loose bone fragments, which can be surgically removed.
Causes
Osgood-Schlatter disease is caused by overuse. Other factors may also play a role; other possible causes that have been suggested include infection or aseptic bone necrosis, though these have not been confirmed by research. Today it's generally accepted that repeated pulling from the patellar tendon is the underlying cause.
What can you do yourself to help prevent this condition?
Unfortunately, Osgood-Schlatter disease cannot always be prevented. However, the risk can be reduced by paying attention to the following:
- Do a full warm-up before and a cool-down after training or a match, each lasting around 10-15 minutes. Pay particular attention to correctly performed stretching exercises, especially for the calf muscles.
- Build up training gradually, so your body can adjust calmly to the extra load.
- Increase sprint and jump exercises gradually, and train a little more lightly the day after an intensive sprint session.
- Avoid doing too many jumping exercises during a growth spurt.
- Make sure you have well-fitting (tennis) shoes with good shock absorption, lateral stability, grip and overall comfort.
- If you have misaligned legs or feet (bow-legs, knock-knees, pronated or high-arched feet), have proper insoles fitted for your shoes and wear supportive footwear.
What can you do yourself if the injury has already developed?
By training less often, and in particular reducing intensity and explosive movements (sprinting and jumping), as well as running in straighter lines, you can still enjoy plenty of sport. If a temporary step back isn't possible and you carry on regardless, you're only setting yourself up for more complaints. There aren't many sports that avoid pain-provoking movements entirely, so alternatives are limited — gentle swimming might be one option. You'll notice that on some days you can do almost everything pain-free, and on others almost nothing. On average, the fluctuating symptoms of this condition last between one and one and a half years. Even once the symptoms have gone, the swelling often remains as a lasting reminder.
Treatment
In principle, this condition is self-limiting, meaning the patient is naturally held back from activities that would cause pain. The best advice is therefore to stop all painful activities for the first 2 months, extending this period by 1 to 2 months if necessary. Complete immobilisation (making the painful knee entirely motionless) is only needed in severe cases. Endurance training can then be resumed gradually, taking into account the load involved in activities such as cycling to school. Specific training such as shooting, sprinting and jumping should only resume after isometric strengthening, once such loads are possible without pain. Alternative forms of exercise, such as light running, exercise-bike cycling or swimming (front crawl), can be offered in the meantime. With a reduced training load over 3-6 months, every athlete should be able to become symptom-free. A check-up every three months is advisable, so that the period of relative immobility doesn't last any longer than necessary.
Besides avoiding excessive pulling on the tendon attachment, a number of other things can help speed up recovery:
- Wearing a patellar tendon strap, fitted just below the kneecap.
- An ice massage after sporting activity, or during a flare-up of symptoms, can help relieve pain.
- Specific stretching exercises for the thigh muscles can reduce the pull on the knee.
- The physiotherapist may use dry needling or deep transverse friction on the thigh to further reduce the pull on the knee.
- The physiotherapist may also use kinesiology tape to ease the complaint.
- In rare cases a cast is applied to rest the knee. If symptoms persist into later life, surgical removal (extirpation) of loose fragments may be considered. Normally, the inflammation resolves completely.