A device and method of manufacturing and implanting a custom subtalar arthroereisis implant having side surfaces which are mirrored in topography with the sinus tarsi of a patient. The implant is formed using images of the patient standing in a weight bearing position with their sinus tarsi and the surrounding bone structure in an anatomically correct alignment. Once implanted, the implant urges and maintains the anatomically correct alignment thereby minimizing any patient tendency for abnormal motion between said patent's talus and calcaneus.
