Fat injections can be done to the calves or other body areas but it might require several sessions as not all fat lives from one transfer. There are risks though and you should discuss this with your surgeon, including a lack of survival, nodules and uneven contour, infection, hematomas and bleeding, etc.
I Have Slim Legs with Very Muscular Calves Can Fat Transfer Be the Solution?
Doctor Answers 2
Fat injections to legs
Fat can be injected anywhere.
Fat can be injected into almost any area of the body, and is limited only by the creativity of the surgeon. The lower calves are a very difficult area to augment. If you wish to augment the upper calves as well, implants can be placed lower than the end of the calf muscle, and will provide fullness for the mid calf regions. There is a limit as to how low you can place the calf implant however.
For the lower third of the leg probably the only option is fat grafting.