Constrained shoulder and hip arthroplasty

An apparatus comprising:

• a) a scapular baseplate comprising:
• i) a scapular bone connecting component,
• ii) a dowel pin, and
• iii) a glenosphere base connecting component;
• b) a humeral baseplate comprising:
• i) a humeral bone, and/or humeral stem, connecting component,
• ii) a glenosphere recess, and
• iii) a first ring connecting component which comprises a circular peripheral recess that accepts a first retaining ring,
• c) a glenosphere comprising:
• i) a top surface that articulates with said glenosphere recess, and
• ii) a bottom surface that attaches to said glenosphere base connecting component of said scapular baseplate;
• d) a retainer assembly comprising:
• i) said first retaining ring which is expandable by force at a first and second hole, wherein said first retaining ring comprises:
• A) said first hole adjacent to said second hole, B) first and second flexible band attachment or holder sites, on opposite sides of said first and second holes, which accept two ends of a first flexible band that is Y-shaped, C) a third flexible band attachment or holder site which accepts a second flexible band;
• and D) a fourth flexible band attachment or holder site which accepts a third flexible band,
• ii) a second ring, wherein said second ring comprises:
• A) a first flexible band attachment or holder site which accepts said first flexible band, B) a second flexible band attachment or holder site which accepts said second flexible band;
• C) a third flexible band attachment or holder site accepts said third flexible band, and D) a scapular baseplate connecting component which comprises a hole that accepts said dowel pin of said secular baseplate,
• iii) said first flexible band that is Y-shaped:
• A) attached to, or configured to be attached to or held by, said second ring at said first flexible band attachment or holder site, and B) attached to, or configured to be attached to or held by, said first retaining ring at both said first and second flexible band attachment or holder sites,
• iv) said second flexible band:
• A) attached to, or configured to be attached to or held by, said second ring, and B) attached to, or configured to be attached to or held by, said first retaining ring, and
• v) said third flexible band:
• A) attached to, or configured to be attached to or held by, said second ring, and B) attached to, or configured to be attached to or held by, said first ring.