Abstract: The present invention provides systems, devices, and methods for using two or more flexible bands to constrain shoulder and/or hip replacement components to reduce dislocation and/or instability (e.g., constrain the glenosphere against a glenosphere recess, or constrain a femoral head against an acetabular component). In certain embodiments, one end of the flexible bands are attached to, or are held by, a first ring (e.g., expandable ring, such as a snap ring) that is configured to be operably connected (e.g., via a humeral baseplate) to a humeral stem, while another end of the flexible bands are attached to, or are held by, a second ring (e.g., flat ring, washer, annular, hoop, or orbital) that is configured to be operably connected (e.g., via a scapular baseplate) to a scapular bone. In some embodiments, an outer sleeve (e.g.