Tendon Transfer Procedures

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.

Conditions

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.

Surgery

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.

• Foot Drop Treatment (PTT Tendon Transfer):
  For a foot drop, a posterior tibial tendon transfer procedure can involve the posterior tibial tendon alone or transfer with two other tendons, the peroneus longus and the anterior tibialis. When all three tendons are used it is called a Bridle procedure.

  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.

• Flexor to Extensor Tendon Transfer:
  Your foot and ankle orthopaedic surgeon makes an incision on the bottom of the involved toe. There are two tendons to each toe that help to flex or bend the toe. One of the tendons is transferred to the top of the toe. It is then attached to the tendon that extends or straightens the toe through an incision on the top of the toe. A pin may be inserted into the toe to help maintain alignment for a number of weeks after the procedure.
• Flexor Hallicus Longus (FHL) to the Proximal Phalanx Transfer:
  Once the patient is under anesthesia, the foot and ankle orthopaedic surgeon makes an incision along the inside of the toe. The surgeon takes care to protect the nearby nerve and artery. The tendon is released from its attachment and a stitch is placed into the end of it. A hole is drilled in the bone at the base of the toe close to the metatarsophalangeal (MTP) joint. The tendon is passed through the hole from the bottom of the toe up to the top of the toe, and a stitch is used to tie the tendon securely back to itself.

  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.

• Flexor Hallicus Longus to Peroneus Brevis Transfer:
  An incision is made over the course of the PB around the outside of the ankle. The PB is examined carefully and any degenerative portion is removed. A second incision is made on the inside of the foot and the FHL is identified and pulled from the inside of the foot to the outside of the foot where the PB inserts. The FHL can be directly attached with a screw or suture to the bone where the PB inserts. After the tendon transfer, the wound is closed with sutures.
• Flexor Digitorum Longus (FDL) Transfer:
  The PTT connects to the navicular bone near the middle of the foot at the instep. In this surgery, the FDL tendon is moved from its usual position and transferred to the navicular bone. This helps support or replace the diseased PTT to improve function. The diseased PTT is cleaned up or removed to eliminate it as a source of pain.

  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.

• Peroneus Longus to Achilles Tendon Transfer:
  Patients can be placed on their back, side, or face down for the surgery depending on surgeon’s preference and any additional procedures being performed. The PL tendon is identified, cut, redirected and tied into either the Achilles’ tendon with suture or into heel bone with an anchor. The incisions are then closed and a splint is placed on the leg.

Rehabilitation

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.