Hello,
The only time a joint injury is a true emergency is a hip dislocation in these cases time is of the essence to put it back into place. The classic presentation of this is a prominent bump on the hip and the leg appears to be rotated outward also they toe touch. Little dogs tend to have shallow hips so they can dislocate fairly easily and it is most common with a fall or jump. A trip to the ER is indicated they will take an X-ray and if dislocated try to put it back into place. The faster it is put back in place the better as the longer you wait the harder it is to correct and the more likely it is to fail (ie “pop back out”).
The other possibility is a fracture. Little dogs have fragile bones. Although it sounds terrible this isn’t an emergency and cage rest is indicated. See a vet ASAP for an X-ray. An orthopedic specialist should be seen to repair this.
Lastly a knee injury like a cruciate ligament rupture is the next possibility. This is like an ACL in people. It happens with trauma or abnormal forces on the knee associated with playing or turning the leg while the body is in motion. This is often a surgical procedure to correct.
It is also possible to have a muscle, joint, tendon or injury elsewhere which would benefit from rest and analgesics or steroid/NSAID therapy.
In cases like this I have to say it’s best to go directly to the ER for an exam and possible X-ray.
I hope she’s ok.
Keep us posted
I would contact your vet and make them aware of this new behavior right away.
I would worry this is pain. Or stress. There are lots of medications available for these. Please call your vet.