Advantages and drawbacks of proximal interphalangeal joint fusion versus flexor tendon transfer in the correction of hammer and claw toe deformity. A finite-element study.

Correction of claw or hammer toe deformity can be achieved using various techniques, including proximal interphalangeal joint arthrodesis (PIPJA), flexor digitorum longus tendon transfer (FDLT), and flexor digitorum brevis transfer. PIPJA is the oldest technique, but is associated with significant complications (infection, fracture, delayed union, and nonunion). FDLT eliminates the deformity, but leads to loss of stability during gait. Flexor digitorum brevis tendon transfer (FDBT) seems to be the best surgical alternative, but it is a recent technique with still limited results. In this work, these three techniques have been analyzed by means of the finite-element method and a comparative analysis was done with the aim of extracting advantages and drawbacks. The results show that the best technique for reducing dorsal displacement of the proximal phalanx is PIPJA (2.28 mm versus 2.73 mm for FDLT, and 3.31 mm for FDBT). However, the best technique for reducing stresses on phalanges is FDLT or FDBT (a reduction of approximately 35% regarding the pathologic case versus the increase of 7% for the PIPJA in tensile stresses, and a reduction of approximately 40% versus 25% for the PIPJA in compression stresses). Moreover, the distribution of stresses in the entire phalanx is different for the PIPJA case. These facts could cause problems for patients, in particular, those with pain in the surgical toe.