Do you have a flat foot with pain at the inside of your ankle? Many times, this is due to posterior tibial tendinitis. The posterior tibial tendon allows you to invert your foot and get up onto your tiptoes while standing. When this becomes inflamed and degenerative, the foot can start to deform. There are several ways to treat this, but the most common involves performing a lengthening of the calf muscle, an osteotomy of the heel bone (cutting it and shifting it medially) and then reconstructing the medial tendon and ligaments in order to improve the shape of the foot. Many parts of this surgery can now be performed via MIS, including the calf lengthening which may be done using two keyhole incisions and an endoscopic camera to find the tendon and lengthen it, as well as the calcaneal osteotomy, which is done via a 5mm incision rather than a 2 inch incision on the outside of the foot. The benefits for pain, scarring and accidental injury to nerves and veins are lower with the MIS technique. The yellow line shows the extent of the open incision, as compared to the MIS incision, shown in red.