ENGINEERING ANALYSIS OF A FAILED COMPASS PROXIMAL INTERPHALANGEAL (PIP) JOINT HINGE

A failed compass hinge external fixator for fingers has been analyzed. The device consists of polymer parts manufactured from polyetherimide. Finite element analysis (FEA) was used to investigate the principal stresses in the device under different loading conditions. Scanning electron microscopy (SEM) was used to investigate the fracture surfaces. The FEA showed that the maximum principal stress was greater than the fatigue strength of polyetherimide. The SEM fractographs confirm that failure was by brittle fatigue.