The most common and most likely answer to this crossword clue is the 9 letter word ARTICULAR
I've seen this crossword clue in The Daily Telegraph
A
R
T
I
C
U
L
A
R
More clues leading to the result ARTICULAR
Buddy explains!

The straight part
We know that "connected with joint" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case connected with joint = articular.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does ARTICULAR mean?
ARTICULAR adjective- Of, at, or relating to the joints of the body.
- (grammar) Of or relating to the grammatical article.