A tendon transfer is moving a tendon from its normal, anatomic location to another area of the foot or ankle. Tendons are typically transferred in order to restore more normal movement to a foot and ankle that has lost function. This can result from nerve or muscle damage due to stroke, injury, or other diseases. This muscular weakness or paralysis decreases movement and can lead to the foot becoming bent or twisted, making it difficult or painful to stand, walk or wear shoes.
Some tendon transfers allow the ankle and foot to move up and down and regain strength and motion. Others bring the foot into a position where it is easier to walk, stand and wear shoes, but will not increase range of motion. Realigning the foot and ankle can also decrease pain by more evenly distributing pressure across the foot. In some cases, a tendon transfer may eliminate the need for a brace altogether.
In general, a tendon transfer is a procedure in which a tendon (and attached muscle) that is still working is taken from one part of the foot and moved to another part of the foot to try to replace the missing muscle function. This can be used to treat foot drop, a hammertoe deformity, a claw toe, outward movement of the foot and ankle, fallen arches, strength in the achilles tendon, and more.
Bent Toe Disorders (Hammer, Mallet and Claw)
A bent toe disorder is an oddly bent toe joint. Hammer, claw and mallet toes are often painful and commonly occur in one or more of the four smaller toes.
Progressive Flatfoot (Posterior Tibial Tendon Dysfunction)
If this tendon becomes inflamed, overstretched, or torn, you may experience pain on the inner ankle and gradually lose the inner arch on the bottom of your foot, leading to flatfoot.
When non-surgical or other surgical treatments fail, a tendon transfer may be necessary.
There are a number of tendon transfer procedures that can be performed depending on the foot and ankle injury.
The posterior tibial tendon is taken off its insertion on the navicular bone on the inner side of the foot. This is the first incision. A second incision is made above the ankle and the tendon and muscle are identified. The tendon is pulled into this second incision and then transferred in between the tibia and fibula bones to the front of the ankle.
Another incision is made on the top of the foot at the bone to which the tendon is going to be transferred. The tendon is routed under the skin to this bone and fixed into a tunnel in the bone.
If a Bridle procedure is performed, a second tendon, the peroneus longus, is cut above the level of the ankle on the outer side of the leg. This tendon is then routed to the front of the ankle and the free end is attached to the posterior tibial tendon and the anterior tibial tendon in a bridle configuration. With this construct the posterior tibial muscle pulls on all three tendons to pull the foot up. The posterior tibial tendon is routed to the top of the foot as described above.
Occasionally, the ankle can be very stiff from long-standing weakness. If it is not possible to pull the ankle up for attachment of the tendon transfer, the Achilles tendon is lengthened to help bring the foot and ankle up. This is done either through an incision on the calf or an incision right over the Achilles tendon. The location of the incision is based on which portion of the Achilles is too tight.
Although releasing the tendon can allow the toe to straighten, release of the contracted joint capsule often is necessary as well. In many cases, the FHL tendon transfer is used in combination with other procedures to correct other foot deformities.
The surgery is done through an incision on the inside of the ankle and foot. The initial step is to remove the scarred or inflamed tissue of the PTT. The tendon may be completely removed if it is severely damaged. Just below the PTT is the tendon of the FDL. The FDL is cut so that it is as long as possible. A hole is drilled in the navicular bone. The end of the FDL is placed through the bone. While the foot is held in the corrected position, the tendon is attached to the bone. It may be held in place with stitches and/or an anchor or screw. The incision is then closed. Other procedures may be performed with the tendon transfer to improve the arch. These can include moving or shifting of bones and stretching of the calf muscles or Achilles tendon.
After surgery, no weight is placed on the leg for a period of time. A cast boot will be used at some point to protect the transfer while allowing removal for therapy and hygiene. After a few months the boot will be removed and physical therapy will start. While recovery from surgery may take three to six months, but it may take a full year for all symptoms to fully resolve.