Is a “jarred” knee a “dislocated” knee?
No, it is not necessarily dislocated and it probably isn’t dislocated but it has suffered some kind of assault. Maybe it has been twisted, compressed or struck and it may have some internal injury such as a torn ligament.
So…a jarred knee is simply an injured knee? Is it the idea?
“Jarred” is not a medical term so it cannot be precisely defined like “dislocated” can. Even as a word, “jarred” defies easy description (see my first response). In any case, “jarred” is a word the person can use to tell you in what manner his knee was injured; it is not a description of the resulting damage to the knee, if any.
In summary then, a “jarred knee” has suffered some trauma but one can’t know what, if any, actual damage to the knee has been caused.
Where did you find “jarred knee”? If someone tells you they have a “jarred knee”, ask them what they mean!
I assume you read “jarred knee” in a text. Didn’t you get any clues as to the meaning from the rest of the context?
Without any context, I would tend to understand that the knee had been bumped fairly hard, but that any resulting injury is nevertheless minor.
I would assume that nothing was broken, dislocated, or even sprained, but there could be some bruising and low-level residual pain after the bump.
To me, saying that a knee has been jarred gives the impression that there was a shock (a sudden blow/bump), but not much more.
The verb ‘to jar’ implies some form of rough contact which, at most, only temporarily disrupts function. Usually such impairment is relatively minor and quick to resolve itself. A ‘jarred’ knee may hurt for a little while, but any actual damage is transitory and not seriously disabling.