Osgood-Schlatter disease

What is Osgood-Schlatter disease, and how common is it?

Osgood-Schlatter disease is an overuse injury that causes pain and inflammation at the tibial tubercle (the bony bump just below the kneecap, where the patellar tendon attaches to the shin bone). It mostly affects young people who are still growing¹. The clinical name is tibial tubercle apophysitis, which means irritation of the growth area at that spot.

It's the most common cause of knee pain in active teenagers, and the bump often stands out². Up to 10% of adolescents have it³⁴. It's more common in young people who play sport³, and in boys. It usually appears between about 11 and 15 years of age⁵.

What causes it, and who gets it?

It comes from repeated pulling. During running, jumping and bending, the thigh muscles (quadriceps) pull through the patellar tendon on the growth area at the top of the shin bone, and the area becomes inflamed⁶.

Growth spurts add to this. Because the skeleton lengthens ahead of the muscles, those muscles must lengthen to keep pace and can end up tight. Tight muscles pull harder on the bump, which causes pain, particularly during exercise⁷. Kneeling can also make it worse⁸.

Sport is linked with higher rates, and sport is likely to increase how often it happens³. That doesn't prove sport is the cause in any one child. The people most affected are active teenagers going through a growth spurt⁸.

What does it feel like, and what else could it be?

The usual picture is pain, swelling or tenderness just below the knee, which tends to be worse during or after activity. Running, kneeling, jumping and stairs often bring it on⁹. The pain varies in how strong it is, and a small tender bony bump may develop¹⁰.

Diagnosis is usually based on the typical symptoms and an examination. The examination looks for tenderness over the bump and pain when the knee is straightened against resistance¹¹. When the picture is typical, X-rays or scans aren't normally needed⁸.

When young people have knee pain, serious causes such as infection and tumour are ruled out¹². Some features aren't typical of Osgood-Schlatter disease and can point to another cause:

• swelling or bruising that doesn't improve with rest or elevation
• regular or constant night pain
• numbness or persistent pins and needles
• fever, or redness and heat around the hip, knee or ankle
• a sudden, unexplained limp, or being unable to walk on the leg¹⁰

In children, pain that wakes them at night is linked with tumour. Redness, swelling or stiffness of a joint is linked with infection or inflammatory joint disease. Weight loss, fever, night sweats or tiredness can go with tumour, infection or inflammation¹³. Septic arthritis (a joint infection) is an emergency, because it can destroy a child's joint within 24–48 hours¹³.

Swelling soon after an injury, with a large, tense swollen knee, can mean bleeding into the joint¹¹. A tibial tubercle fracture is a separate injury at the same spot, with a considerable risk of complications and repeat operations¹⁴. A knee that locks, gives way or clicks painfully is also worth knowing about, while painless clicking is normal¹⁵.

What helps first?

Care starts with simple steps at home. Several of them work together:

• Adjust activity. Jumping, running and kicking are limited until they can be done without pain, which can sometimes take several months². Lower-stress options such as swimming, gentle cycling or a cross trainer can keep a young person moving¹⁰. School can be told, as PE lessons may need to be less vigorous⁹.
• Ice after activity, with a towel between the ice and the skin¹⁰. The Try this box below shows how.
• Stretch gently. Regular hamstring and quadriceps stretching for 20–30 seconds, if pain allows⁹.
• Use simple pain relief. Paracetamol is often used⁶. Pharmacists can talk through the options⁹.
• Try physiotherapy. Physiotherapists teach exercises to stretch tight muscles and tendons⁶.

Knee immobilisation, such as a splint, isn't recommended².

How much to cut back depends on the pain. Some advice is to limit jumping, running and kicking until they're pain-free. Other advice is that sport can continue as tolerated, and that over-treatment should be avoided because the condition is benign and settles by itself⁵. Either way, any exercise that increases knee pain is best stopped. Sport is unlikely to cause lasting damage, but it can make the pain worse⁸.

Stretching appears to help, but most common treatments aren't well proven¹⁶⁴. It isn't clear yet whether insoles, straps or taping help the knee. In children's heel pain, which is a different problem, foot orthoses made little difference compared with heel lifts¹⁶.

What can help if that isn't enough?

Most young people don't need more than first-line care. Non-surgical treatment works well for managing Osgood-Schlatter disease, and surgery is uncommon. It appears to be kept for people whose growth plates have closed and whose symptoms persist¹.

Orthopaedic review (by doctors who treat bones and joints) is considered when significant impairment continues despite conservative care². Some young athletes have a separate small piece of bone (an ossicle) in the patellar tendon. It can cause long-lasting pain, and removing it may be considered⁵. How long first-line care should be tried before moving on isn't clear yet.

How long does it last, and can it come back?

Osgood-Schlatter disease settles by itself, and full resolution is expected². Symptoms should go once the young person has finished growing, but the bump will usually stay prominent².

The discomfort can last weeks to months, and it may come and go until growth has stopped⁶. Pain can ease before sport is back to normal. Getting back to full sport can take months, so a gradual return guided by pain makes sense¹⁷.

What speeds recovery, and what stops the pain coming back, isn't clear yet.