The foot is controlled by balanced muscles. What I mean by this is that for every muscle that pulls your foot down, there is one about the same strength that pulls your foot up. Same goes for every toe and for every motion - for every muscle that pulls the foot inward there is one that counterbalances and pulls the foot outward.
As you can imagine if one muscle is injured for whatever reason, the opposing muscle will pull foot in opposite direction. Over time this creates defomities and contractures of joints that can make movement and walking impossible or difficult at best.
With tendon transfers we move tendons around and rebalance those natural motions. For example in a condition called dropfoot ( click here for a video ) the muscles that pull the foot upward cease to function. The downward pulling muscles are the only functioning muscles making it impossible to walk normally. We reroute a one of those downward pulling muscles from the back to the leg to the front of the leg to force them to pull the foot upward hence fixing the dropfoot. Other muscles then step in and are able to pull the foot downward to rebalance the entire limb.
There are other situations where various tendon transfers are needed such as in amputations where certain muscles were removed and imbalance occures, there are other tendon techniques we use , splitting tendons in half, creating new tendons for damaged muscles, even occasionally reinnervating muscles to recreate function.
Recently we have been using EEG technology to measure brain wave function of our patients and use this information to learn which tendon transfer to do as well as using this advanced technique to retrain their muscles after the transfer surgery. To learn more about this click HERE