The Achilles tendon connects both calf muscles (gastrocnemius and soleus) to the heel bone. When it is too tight it holds the foot pointed down so the heel can’t reach the floor. An Achilles lengthening cuts and lengthens the tendon — often through several small “Z” or sliding cuts (percutaneous or open) — so the foot can sit flat. It lengthens more of the calf than a gastrocnemius recession, which makes it useful for more severe or combined contractures, but it also weakens push-off more, so surgeons reserve it for tightness that isn’t limited to the gastrocnemius alone.
Performed under anesthesia. In the common percutaneous technique the surgeon makes two or three small nicks and partially cuts the tendon at different levels so it slides to a longer length as the foot is brought up to neutral; open Z-lengthening is used for larger corrections. A cast usually holds the foot in the corrected position afterward.
Typically a cast or boot for several weeks, then physical therapy to rebuild calf strength and a normal heel-to-toe gait. Bracing (an AFO) is sometimes used afterward, especially in cerebral palsy. Full return to activity generally takes a few months.