Clin Should Elbow.  2011 Jun;14(1):105-110.

Reverse Total Shoulder Arthroplasty: Where we are? "Principles"

• Noh KC
• Suh IW

Abstract

PURPOSE
The purpose of this article is to identify and understand the complications of RTSA and to review the current methods of preventing and treating this malady.
MATERIALS AND METHODS
Previous constrained prostheses (ball-and-socket or reverse ball-and-socket designs) have failed because their center of rotation remained lateral to the scapula, which has limited of the motion of the prostheses and produced excessive torque on the glenoid component, and this leads to early loosening. The Grammont reverse prosthesis imposes a new biomechanical environment for the deltoid muscle to act, thus allowing it to compensate for the deficient rotator cuff muscles.
RESULTS
The clinical experience does live up to the lofty biomechanical concept and expectations: the reverse prosthesis restores active elevation above 90degrees in patients with a cuff-deficient shoulder. However, external rotation often remains limited and particularly in patients with an absent or fat-infiltrated teres minor. Internal rotation is also rarely restored after a reverse prosthesis. Failure to restore sufficient tension in the deltoid may result in prosthetic instability.
CONCLUSION
Finally, surgeons must be aware that the results are less predictable and the complication/revision rates are higher in revision surgery than that in the first surgery. A standardized monitoring tool that has clear definitions and assessment instructions is surely needed to document and then prevent complications after revision surgery.

MeSH Terms

Deltoid Muscle
Humans
Prostheses and Implants
Rotator Cuff
Scapula
Shoulder
Torque