Leprosy
mailing list, July 13th, 2005
To: all.
Ref.: Intrinsic plus
deformity.
From: H Srinivasan, India.
Dear Salvatore,
I just now happened to see Dr
Schwarz's clarification on intrinsic plus deformity (LML -
June 9th, 2005). I am afraid I have to make some comments.
By definition, this deformity
has two components: flexion ay MCP joint and hyperextension (HE) at
PIP joint. As a consequence of the latter, usually there is an
additional flexion deformity at the DIP joint. You cannot have
contracture of the intrinsic muscles (interossei mainly) without MCP
flexion.
HE of PIP joint without MCP
flexion contracture is seen in some other conditions: sublimis minus
situation, scleroderma involving dorsal skin when it becomes adherent
to the extensor expansion (preventing its volar gliding necessary for PIP
flexion) and some cases of mallet finger. I call these
deformities 'pseudo swan-neck deformities' to distinguish them from
the true swan-neck of the intrinsic plus (contracture or dominance of
the intrinsics - mainly the interossei). It is better to keep the
distinction in mind, as treatments of these conditions are different.
H.
Srinivasan
