A tendon transfer is moving a tendon from its normal, anatomic location to another area of the foot or ankle. Tendons typically are 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, 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 some 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.
There are two common reasons your foot and ankle orthopedic surgeon may recommend a tendon transfer in the foot and ankle. One is 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 foot then rolls inward, leading the patient to walk on the inside of their foot. This can cause discomfort.
The other reason is the loss of function of muscles in the lower leg and foot due to a neurological problem such as injury or disease. This can 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 muscles of the front and outside of the calf. This causes the foot to roll outward and the patient to walk on the outside of their foot. This can cause pain and weakness as well as bone fractures and looseness of the ligaments on the outside of the foot.
Tendon transfers usually are 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 canceled.
There are three requirements for tendon transfers to be successful:
- The muscle that the tendon is attached to has to be functional. It must contract at the proper time during walking.
- 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 also can prevent the tendon from gliding along the correct path.
- The joints that the tendon crosses need to be both mobile and stable.
Tendon transfers involve the cutting of the tendon at or near 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 also can be brought into a bone tunnel and fastened with a screw made of metal or an absorbable plastic. An anchor with sutures attached to it also can 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.
Typically the splint stays on the patient’s leg for 10-14 days. At that point the splint and sutures are removed. The patient is then placed in a cast or a removable boot.
Patients typically are non-weightbearing 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.
Physical therapy usually is 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.
Risks and Complications
All surgeries come with possible complications, including 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 requiring further surgery.
Will my foot move normally after the tendon transfer?
It depends on which tendon transfer you have. Some tendon transfers act as a leash for the foot and simply hold it in proper alignment. This does not necessarily provide much movement for your ankle and foot. Other tendon transfers move functional muscles from one side of the foot to the other, and therefore the foot should have a more normal movement after these procedures. The goals for the surgery and recovery should be discussed with your foot and ankle orthopedic surgeon before proceeding with any procedure.