The subtalar joint arthroeresis procedure has been around since the 1940's although it was very different back then. Arthroeresis means joint-blocking and it is done the block the motion of the subtalar joint. Why? It is the subtalar joint that is resposible for allowing the foot arch to go into a collapsed position. The motion in that joint is limited with the arthroeresis but some motion is preserved - as opposed to an arthrodesis procedure where we remove the joint completely and fuse it so no motion occurs. the implant simply blocks the foot joint from dropping the arch.
Throughout the 1940's and 50's, procedures were developed to reduce motion in that subtalar joint, cutting bone a specific way was used widely to create a stopper inside the joint. In the 60's and 70's surgeons also fashioned implants out of silicone or plastic to stuff into the outside of the joint to acheive the joint motion limiting. In the 80's and 90's a few commercially available implants were introduced that were small metal implants that could be placed through a small incision usually less than an inch long into the subtalar joint. These are in use today and are a common procedure for flatfoot correction. The patient selection is key, only a certain type of flatfoot should be corrected with this method and many times a lengthening on the achilles tendon needs to be done in conjunction. It is the surgeons job to properly examine the foot to judge this for the best possible outcome.
originally these procedures were done in children before complete bone and joint maturity meaning that if the implant was placed at an early enough age the joint itself would adapt to the new limited range of motion. At some point the child would 'grow out of the implant' and it would no longer be needed. The joint itself wound have changed enough to keep the flatfoot straight. In the past ten years the implants have been used more in adults with good success as well but again - the surgeon needs to identify which feet the implant will help. Many times fusion of joints or cutting the bones may give a better long lasting result.