The Reverse Shoulder Prosthesis (RSP®) was the first reverse shoulder design to successfully incorporate a center of rotation (COR) lateral to the glenoid.
Clinical Challenge:
Patients presenting with an irreparable, rotator cuff deficient shoulder joint with severe arthropathy typically show evidence of an upward displacement of the humeral head with respect to the glenoid and a loss of glenohumeral joint space. Unfortunately, the functional outcomes using conventional surgical methods are severely limited and typically fail.
Clinical Solution:
The Reverse® Shoulder Prosthesis is a semiconstrained design concept that reverses the shoulder anatomy by lateralizing the shoulder joint to effectively resist the superior pull of the deltoid muscle and optimize soft tissue balancing.
Indications:
• Grossly rotator cuff deficient shoulder joint with severe arthopathy;
• A previously failed joint replacement with a grossly rotator cuff deficient shoulder joint;
• Evidence of upward displacement of the humeral head with respect to the glenoid;
• Loss of glenohumeral joint space
Results:
• Both lateral offset and peripheral screw type affected the magnitude of baseplate motion.
• Baseplate motion for Delta III components and Reverse® Shoulder Prosthesis components fixed with 5.0mm captured screws were below the 150 μm of motion generally accepted as the threshold for bone ingrowth.
• Stable fixation was achieved for the Reverse Shoulder Shoulder Prosthesis neutral components despite a substantially (69%) greater moment at the baseplate-foam interface compared with the Delta III.