Purpose of review: Over the past decade, our understanding of the biomechanics of the reverse total shoulder arthroplasty (RTSA) has advanced, resulting in design adjustments, improved outcomes, and expanding indications. The purpose of this review is to summarize recent literature regarding the biomechanics of RTSA and the evolving indications for its use.
Recent findings: While Grammont's principles of RTSA biomechanics remain pillars of contemporary designs, a number of modifications have been proposed and trialed in later generations to address complications such as impingement and glenoid failure. Clinical and biomechanical literature suggest that less medialized, more inferior glenospheres result in less impingement and notching. On the humerus, a more vertical neck cut is associated with less impingement. Indications for RTSA continue to expand beyond the classic indication of cuff tear arthropathy (CTA). Patients without a functional cuff but no arthritis now have a reliable option in the RTSA. RTSA has also replaced hemiarthroplasty as the implant of choice for displaced three- and four-part proximal humerus fractures in the elderly. Finally, updated design options and modular components now allow for treatment of glenoid bone loss, failed arthroplasty, and proximal humerus tumors with RTSA implants. Reverse total shoulder arthroplasty design has been modernized on both the glenoid and humerus to address biomechanical challenges of early implants. As outcomes improve with these modifications, RTSA indications are growing to address complex bony pathologies such as tumor and bone loss. Longitudinal follow-up of patients with updated designs and novel indications is essential to judicious application of RTSA technology.
Keywords: Biomechanics; Proximal humerus fracture; Reverse total shoulder arthroplasty; Rotator cuff; Scapular notching.
Conflict of interest statement
Caitlin M. Rugg, Monica J. Coughlan and Drew. A. Lansdown declare that they have no conflict of interest.
Expanding Roles for Reverse Shoulder ArthroplastyPN Chalmers et al. Curr Rev Musculoskelet Med 9 (1), 40-8. PMID 26803609.Since its introduction in the USA in 2003, reverse total shoulder arthroplasty (RTSA) has been used with increasingly frequency as surgeons have observed the remarkable i …
Prostheses for Reverse Total Shoulder ArthroplastyJM Kazley et al. Expert Rev Med Devices 16 (2), 107-118. PMID 30669890. - ReviewDespite an expansion in the understanding of the biomechanics of the rotator cuff deficient shoulder and its effect on the reverse total shoulder prostheses, Grammont pri …
Outcomes After Shoulder Replacement: Comparison Between Reverse and Anatomic Total Shoulder ArthroplastyTK Kiet et al. J Shoulder Elbow Surg 24 (2), 179-85. PMID 25213827.TSA and RTSA have similar complication rates, need for revision, patient-reported outcomes, and range of motion at 2 years of follow-up. The use of side-by-side cohorts i …
Reverse Shoulder Arthroplasty Versus Hemiarthroplasty for Treatment of Proximal Humerus FracturesWW Schairer et al. J Shoulder Elbow Surg 24 (10), 1560-6. PMID 25958208.Although HSA remains the most common arthroplasty choice for proximal humerus fractures, RTSA is becoming widely used. Patient characteristics and complications were simi …
Indications for Reverse Total Shoulder Arthroplasty in Rotator Cuff DiseaseGN Drake et al. Clin Orthop Relat Res 468 (6), 1526-33. PMID 20049573. - ReviewIn short-term followup the RTSA relieves symptoms and restores function for patients with cuff tear arthropathy and irreparable rotator cuff tears with pseudoparalysis (p …