Knee pain in children and adolescents
Knee pain is common during growth and sport. Different causes can produce very similar symptoms: age, activity, duration, swelling or limping and the assessment of the whole limb matter more than the point the child indicates.
In brief
Possible causes include load and sport, Osgood-Schlatter, Sinding-Larsen-Johansson, anterior (patellofemoral) knee pain, patellar instability or dislocation, and osteochondral lesions such as osteochondritis dissecans. One point matters more than any list: in children, pain felt at the knee can come from the hip.
The main groups of causes
Growth and sport-related pain
In children and adolescents who play sport, knee pain frequently involves the tendon insertions around the kneecap. The site of the pain and the age at which it appears differ between these conditions, and so does the way they are followed over time.
The kneecap and instability
Some children describe the knee giving way, or an episode in which the kneecap moved out of place. Here the assessment looks at the extensor mechanism and at limb alignment as a whole, not only at the painful point.
Osteochondral lesions (OCD)
Osteochondral lesions can present with persistent pain, sometimes associated with swelling or mechanical symptoms. The diagnosis requires a clinical assessment and, when indicated, imaging.
Depending on the cause and on the phase of growth, the pathway can include a temporary change in activity and conservative treatment, rehabilitation when indicated and, in selected cases, surgery. The choice depends on the diagnosis and on the individual child: the pages linked above cover each situation in more detail.
Sometimes the problem is not in the knee
A hip problem can be perceived as pain in the thigh or in the knee, with a knee that looks entirely normal on examination. This is one of the reasons why the hip is part of the assessment even when the child points only at the knee.
Slipped capital femoral epiphysis is particularly relevant in adolescents and can present with knee pain and a change in the way the child walks. Other hip conditions can behave in a similar way, which is why the hip is examined rather than excluded on the basis of where the pain is felt.
Other possible causes
Less frequently, knee pain in a child relates to inflammatory joint conditions, to infections, or to bone and joint problems that are not linked to sport at all. These are not the first hypotheses, but they are part of the reason why a knee that hurts persistently, swells or becomes stiff is assessed rather than simply rested.
Why the site of the pain is not enough
Two children can point at exactly the same spot and have completely different situations. Age, the phase of growth, the type and amount of sport, how long the pain has lasted and what the knee does under load all change the interpretation. For this reason this page is meant to orient, not to allow a diagnosis to be made at home.
“When a teenager comes in for knee pain, I always look at the hip as well. It takes a minute and it is the one thing that, if skipped, can send the whole assessment in the wrong direction. Most of the time it is the knee. But the times it is not, it matters a great deal.”
What I assess during the visit
- • The way the child walks and runs
- • Limb alignment and how load is distributed
- • Knee movement and stability, comparing both sides
- • The kneecap and the extensor mechanism
- • The hip, whenever the picture makes it relevant
- • Foot and the rest of the limb, because the knee rarely works in isolation
Are investigations always needed?
Investigations are requested only when the clinical assessment indicates it. History and clinical examination guide the diagnostic pathway in most cases and help establish whether further investigations are needed.
When an assessment can be useful
- • Pain that persists or keeps coming back
- • Sport or daily activity limited by the knee
- • Limping
- • Swelling of the knee
- • Reduced movement or stiffness
- • A sense of instability, giving way or locking
- • A picture that the knee alone does not explain well
Knee pain that persists, limits sport or is not clearly explained? A paediatric orthopaedic assessment can help.
Related conditions
General information only. It does not replace an individual medical assessment.