The Evolution of Reverse Total Shoulder Arthroplasty-From the First Steps to Novel Implant Designs and Surgical Techniques

Abstract

Purpose of review: The purpose of this review is to summarize recent literature regarding the latest design modifications and biomechanical evolutions of reverse total shoulder arthroplasty and their impact on postoperative outcomes.

Recent findings: Over the past decade, worldwide implantation rates of reverse total shoulder arthroplasty have drastically increased for various shoulder pathologies. While Paul Grammont's design principles first published in 1985 for reverse total shoulder arthroplasty remained unchanged, several adjustments were made to address postoperative clinical and biomechanical challenges such as implant glenoid loosening, scapular notching, or limited range of motion in order to maximize functional outcomes and increase the longevity of reverse total shoulder arthroplasty. However, the adequate and stable fixation of prosthetic components can be challenging, especially in massive osteoarthritis with concomitant bone loss. To overcome such issues, surgical navigation and patient-specific instruments may be a viable tool to improve accurate prosthetic component positioning. Nevertheless, larger clinical series on the accuracy and possible complications of this novel technique are still missing.

Keywords: biomechanics; computer navigation; implant design; patient-specific instruments; reverse total shoulder arthroplasty.

Figure 1

Illustration of biomechanical properties in native joint and reverse total shoulder arthroplasty. Relative to the normal anatomy, the center of rotation (CoR) is shifted medially and inferiorly, thus lengthening the moment arm (r) and increasing the deltoid force (F_D). 1: glenoid baseplate; 2: glenosphere; 3: metaphyseal component; 4: humeral stem.

Figure 2

Standard anteroposterior radiographs of the shoulder after reverse total shoulder implantation with different designs and implantation techniques: (A) Right shoulder, cemented Delta XTEND™ (DePuy Synthes, Raynham, MA, USA); (B) Right shoulder, cemented Affinis Inverse (Mathys, Bettlach, Switzerland); (C) Right shoulder, uncemented HUMELOCK™ Reverse (FX Solutions, Viriat, France); (D) Right shoulder, cemented Lima SMR-system (Lima, Villanova, San Daniele del Friuli, Italy); (E) Left shoulder, cemented Tornier AEQUALIS™ ADJUSTABLE REVERSED (Wright, Memphis, TN, USA); (F) Left shoulder, uncemented Comprehensive^® Reverse Shoulder System (Zimmer Biomet, Warsaw, IN, USA); (G) Left shoulder, cemented custom made reverse total shoulder arthroplasty (Zimmer Biomet, Warsaw, IN, USA); (H) Left shoulder, uncemented MyShoulder^® (Medacta, Castel San Pietro, Switzerland).

Figure 3

Standard anteroposterior radiographs of a right shoulder before and after implantation of a reverse total shoulder arthroplasty: (A) Cuff arthropathy of the shoulder with increased posterior glenoid wear. (B) Implantation of an uncemented MyShoulder (R) (Medacta, Castel San Pietro, Switzerland). Additionally, a bony lateral increased-offset harvested from the humeral head was implanted between the glenoid baseplate and the native glenoid (yellow dotted line).