The correction of a paralytic deformity (foot drop, equinovarus and equinovalgus deformity) of the foot by a correctly performed tendon transfer can be satisfying for both the surgeon and the patient. The goal of any tendon transfer to give a stable, functional and plantigrade foot for the patient.
When any tendon transfer is planned the following must be considered-
Also it is important to remember that most muscles will lose a grade of power when transferred particularly if the transfer is not phasic.
Recovery of muscle function may occur for up to one year following the injury, so a tendon transfer may be performed after one year. Waiting longer is not indicated as the foot would be gradually deforming due to the action of the remaining active tendons. A flexible foot deformity is always easier to correct than a fixed deformity, as that would entail doing additional bony procedures.
The most common tendon transferred for correction of a foot drop deformity is the Posterior Tibial Tendon (PTT).The PTT is harvested medially and transferred through the interosseous membrane and inserted over the dorsum of the foot. The tendon is always fixed to bone to ensure faster incorporation of the tendon.
Some patients may have a more global paralytic deformity in which very few tendons remain active. It is a major challenge in those cases to correct the deformity.in such cases where the PTT is paralytic we use the common digital extensors the peroneal tendons or even the Flexor Halluces Longus (FHL) tendon.