CONSTRAINED SHOULDER AND HIP ARTHROPLASTY

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., cylindrical silicone sleeve) is employed that is sized to generally enclose the flexible bands, the glenosphere, and glenosphere recess, or conversely, for the hip joint, the femoral head and acetabular component liner.