10–14 years · Recovery 8–12 weeks with tendon-loading program
Sinding-Larsen–Johansson
SLJ syndrome affects the lower pole of the patella. Repeated traction from the patellar tendon irritates the apophysis during periods of rapid growth, producing front-of-knee pain that worsens with running, jumping and stairs.
Common symptoms
- Pain at the lower edge of the kneecap
- Tenderness to touch on the kneecap tip
- Pain climbing stairs or jumping
- Stiffness after sitting
What causes it
- Growth spurts
- Tight quads and weak glutes
- Volleyball, basketball, athletics
- Spikes in training intensity
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More on Sinding-Larsen–Johansson
Evidence-informed articles for parents and coaches on this condition, growth-related injury and youth athletic development.
Why Do Growth-Related Injuries Happen?
Growth-related injuries are not bad luck. They are the predictable result of demand outrunning capacity at a specific point in development.
ReadCan You Prevent Growth-Related Injuries in Young Athletes?
You cannot prevent growth. You can meaningfully change the odds, and the things that work are simpler and cheaper than most parents expect.
ReadAdolescent Knee Pain: Red Flags That Need Assessment
Most adolescent knee pain is load-related and self-limiting. A short list of features should prompt clinical assessment instead.
ReadKnee Pain in Children: The Common Causes and What to Do Next
Where the knee hurts tells you most of what you need to know. This is the parent's map of the four or five things that account for the vast majority of knee pain in young athletes.
ReadWhy Do Growing Children Get Knee and Heel Pain?
Knee and heel pain cluster in growing athletes for a specific, well-understood reason - and once you understand it, the management makes sense.
ReadHow Much Training Is Too Much for a Young Athlete?
There is no universal number - but there are reliable thresholds, warning signs and a simple way to keep track.
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