PIP joint hyperextension and DIP joint flexion

What is a Pseudo-boutonniere deformity? Pseudo-boutonniere deformity, also known as “pseudo-boutonniere,” is a hand deformity that resembles the classic boutonniere deformity but has different underlying causes and mechanisms. The condition involves the abnormal positioning of the fingers, typically affecting the middle joint of the finger (proximal interphalangeal joint or PIP joint) and the distal interphalangeal…