The most common and most likely answer to this crossword clue is the 15 letter word DISARTICULATION
I've seen this crossword clue in Independent
D
I
S
A
R
T
I
C
U
L
A
T
I
O
N
Buddy explains!
The straight part
We know that "Elbow may split due to this" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case elbow may split due to this = disarticulation.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.