They were injured even in the first movie. No one can honestly believe that Littlefoot and Cera didn't get hurt during their fight. They were really ramming into each other, knocking each other around, there's just no way they didn't get hurt from that, even if it was just bruising.
I'm not talking about the occasional "boo-boo" which you can forget about it less then 10 seconds. There's plenty of those:
1. When Littlefoot got scratched by Petrie when he climbed up on Littlefoot's head in 1
2. When Littlefoot and Cera fought in 1
3. When Cera bumped into a stalegmite in 1
4. When, after the landslide Petrie said "Me hurt all over" in 2
5. When Chomper bit Cera in 1
6. When Ali bit Littlefoot in 4
7. When Littlefoot bumped his head on the log at the beginning of 5
8. When Ducky smashed her hand on Spike's tail in 5
9. When Littlefoot got his tail bitten by Spike in 5
10. When Littlefoot tailwhipped himself in 6
11. When Littlefoot got a rock dropped on his toes by Petrie in 6
12. When Littlefoot rolled over on a pinecone in 7
13. When Ducky smashed her foot onto a rock in 8
And so on. There's no shortage of those. But real injuries? The one you mentioned was from the TV series, I'm talking about the film series. The fact that we had to wait until the tv series to see many real injuries is enough to prove my point. I even googled "Land Before Time injuires"...and got a result for
a topic I made on this site questioning why they hardly ever happen. Serriously, what's up witht this?