1. Tendon Transfers What are tendon transfers?
Tendons are typically transferred in order to restore more normal movement to a foot and ankle that has lost function.
A common problem is loss of the ability to raise the foot up, which is called foot drop.
This can result from nerve or muscle damage due to stroke or injury.
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.

2. What are tendon transfers?
Some tendon transfers allow the ankle and foot to move up and down and regain some 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.

3. What are the goals of a tendon transfer?
This surgery’s primary goal is to get the ankle and foot into proper alignment.
This can allow the ankle and/or foot to be successfully braced for walking and standing.
In some cases, a tendon transfer may eliminate the need for a brace altogether.
This realignment can also decrease pain by more evenly distributing pressure across the foot.

4. What signs indicate a tendon transfer may be needed?
Two common indications for tendon transfer in the foot and ankle.
A painful, flexible flatfoot. This develops when the posterior tibial tendon stretches and becomes nonfunctional or ruptures, which can cause the arch of the foot to drop.
The patient’s foot then rolls outward and walks on the inside of the foot. This can cause discomfort.

5. What signs indicate a tendon transfer may be needed?
The loss of function of muscles in the lower leg and foot due to a neurological problem.
Include weakness after a stroke, nerve damage after a surgery or accident, or a systemic disease causing weakness of the muscles such as Charcot-Marie-Tooth disease.
These problems most typically weaken the musculature of the front and outside of the calf.
This causes the foot to roll inward and the patient to walk on the outside of their foot. This can cause pain and weakness as well as bone fractures on the outside of the foot.

6. When should I avoid surgery?
Tendon transfers are usually elective procedures. Any medical problems which make surgery more dangerous or difficult, such as a recent heart attack, stroke, blood clot or infection, may require the procedure to be delayed or cancelled.

7. Three requirements for tendon transfers to be successful.
First, the muscle that the tendon is attached to has to be functional. It must contract at the proper time during walking to do what it needs to do.
Second, the soft tissue through which the tendon is to be transferred needs to be as normal as possible. Large areas of scarring or skin damage can make it difficult to transfer the tendon.
It can also prevent the tendon from gliding along the path it must travel in order to function as planned. And third, the joints that the tendon crosses need to be both mobile and stable.

8. General Details of Procedure
Tendon transfers involve the cutting of the tendon at its normal insertion, rerouting it through the soft tissues either around or between the bones of the foot and ankle, and connecting it to another bone in the foot.
When the transferred tendon is long enough, it can be passed through a tunnel drilled through the target bone and then sewn to itself.
The tendon can also be brought into a bone tunnel and fastened with a screw made of either metal or an absorbable plastic.
An anchor with sutures attached to it can also be placed in the bone at the point the tendon is to be attached and the sutures used to sew the tendon to the anchor. The soft tissues are then closed and the patient is placed in a splint.

9. What happens after surgery?
Typically the splint stays on the patient’s leg for 10 to 14 days.
At that point the splint is removed and the surgical sutures are taken out. The patient is then placed in a cast or a removable boot.
Patients are typically non-weight bearing for six weeks after surgery to allow the transferred tendon to heal to its new attachment.
This can be longer or shorter depending on what is seen during surgery. After six weeks, patients usually start to bear more weight on the leg and are placed in a boot if they aren’t in one already.
Patients are out of the cast or boot by 12 weeks after surgery.

10. What happens after surgery?
Physical therapy is usually needed to regain the strength of the transferred muscle and to help the patient learn to walk more normally.
The transferred muscle is weaker than it was in its original functional position because of the transfer.
There may be some limitations in motion of the foot due to the tendon transfer, but the function regained by the transfer should outweigh the function lost.

11. Potential Complications
There are complications that relate to surgery in general. These include the risks associated with anesthesia, infection, damage to nerves and blood vessels, and bleeding or blood clots.
Sometimes the tendon transfer does not heal into its new position. The implant could break or loosen, or there could be progression of the original neurologic condition needing further surgery.

12. Clawing big toe with equino-cavo-varus
Case I C
S/P Lengthening of Achilles tendon ( Stage I )
S/P Tenodesis of EHL in the 1st.M-T bone &
fusion of the I.P. joint with pin ( Stage II )

15. Further reference : Clinics in Podiatric Medicine and Surgery
Principles and Biomechanical Considerations of Tendon Transfers
Laura Walton DPM and Matthew F. Villani DPM
Clinics in Podiatric Medicine and Surgery, , Volume 33, Issue 1, Pages 1-13, Copyright © 2016 Elsevier Inc.

16. Q & A
Dr. 熊永萬
Dr. Bear