Superficial versus deep transfer of the posterior tibialis tendon.

Transfer of the posterior tibialis tendon to the dorsum of the foot is a commonly performed procedure in conditions that weaken ankle dorsiflexors and evertors, resulting in equinovarus foot deformities. When transferring the tendon, surgeons have the choice of routing the tendon deep to the extensor retinaculum or superficial to it. This study compares the biomechanics of these two routing methods. Seven cadaveric lower limbs were tested by applying known forces to the transferred posterior tibialis tendon. Resultant kinematics indicated that passing superficial to the retinaculum resulted in a significantly more efficient motion than transfer deep to the retinaculum.