3 year old knee injury

I have a 3 year old boy who was double bounced last month on the trampoline.  He wasn't able to walk for a day and his knee would give out for days after the incident.  He keeps having reinjuries to where he can't run or falls when running.  He's been limping quite often also.  I'm wondering at what age can ligament damage happen and has anyone had a child with a knee injury...a similiar one?

[ChristineMP]

You need to have him seen by an orthopedist. In the meantime, he should wear a full knee brace to avoid re-injuring the joint.

[margypops]

Spring and summer are where trampoline injuries peak,37% of injuries are children under 6 years old ,83% occur when there is more than one child on the trampoline.It sounds like a sprain to the knee ligaments and may take a few weeks. I think it may depend on whether its torn or stretched 2-6 weeks healing time .I think a visit to the Doctor is in order ..Let us know how he is doing good luck Beau