By the excruciating pain of it ... and some difficulty in walking a straight line. If you suspect this has happened, please seek the advice of a medical professional as soon as possible and have the hip x-rayed.
You will have unequal legs, the one with hip dislocation is shorter than the other.
See a doctor!
The first sign would be pain, as dislocating your hip (regardless of whether it is an implant or your own bone) strains and rips a bunch of ligaments and muscles around the socket. Also, you would likely have difficulty putting any weight on that leg and possibly you would not be able to walk at all. You may also be able to feel that the bone is not in the correct location, particularly if you compare the suspect hip to the other hip.
If your shoulder commonly comes out of its socket, then it is a preexisting condition. If it is the first time you have dislocated your shoulder or if you have never dislocated your shoulder, then it is not a preexisting condition.
He will be limping
A dislocated shoulder or knee can be quite painful.
the only one i know is someone dislocated their shoulder in weightlifting, ouch!
Dislocated Shoulder
it is bad
it is damaged
The shoulder joint is the most easily dislocated joint in the body due to its wide range of motion and relatively shallow socket. It is common for the shoulder to dislocate when the arm is forced into an extreme position or experiences a sudden impact.
Take it to the vet and let him do it
It just has to be put back into place.
A dislocated shoulder is typically very painful, causing sudden and intense discomfort. The pain is usually exacerbated by movement and can radiate down the arm. Immediate medical attention is needed to relocate the shoulder and manage pain.
The medical uses for a shoulder brace are to protect the shoulder and keep it in place usually after a shoulder injury. These are often used when one has dislocated a shoulder.