The RSA with a lateralized glenosphere implant improves active shoulder motion and clinical and functional outcomes in selected patients with rotator cuff arthropathy or pseudoparalysis. The clinical and functional outcomes after lateralized RSA seem comparable to those previously reported for Grammont design implants, but with the newsworthy lower rate of scapular notching.
The use of reverse shoulder arthroplasty (RSA) has been constantly increasing and indications have expanded for many diagnoses. Medialization of the centre of rotation is one of the causes of glenoid notching and poor range of motion improvement. A more lateralized RSA has been suggested either at the glenoid or humeral side, but lateralizing the RSA yields a greater moment arm, generating greater torque at the glenoid baseplate-bone interface, which creates apprehension about early loosening and failure The aim of this systematic review was to scope analyze the influence on the clinical and functional outcomes of reverse shoulder arthroplasty lateralized at the glenoid side in patients with rotator cuff arthropathy and/or pseudoparalysis.
A systematic review was performed according to guidelines of Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). Pubmed and EMBASE databases were searched up to January 31, 2020. We included studies that comprised male or female adults with rotator cuff arthropathy or pseudoparalysis with or without osteoarthritis and that the RSA procedure was performed with a lateralized design implant. We excluded studies with less than 10 patients, that comprised patients reporting fractures, instability or escape, infection, rheumatologic or neurologic diseases, patients with revision surgeries or failed shoulder arthroplasty, and studies reporting only revision arthroplasties or mixed population that did not sub grouped the primary RSA. The Methodological Index for Non-Randomize Studies (MINORS) was used to assess study methodological quality.
We included 9 studies comprising 6 retrospective studies (level III) and 3 prospective case series (level IV). The mean MINORS score was 11.7 ± 4.3. In total, there were 1,813 patients (61% female) with a mean age of 72.2 ± 3 years (range, 43-95) that underwent RSA with a lateralized design. The most common indications included pseudoparalysis without osteoarthritis (n=362), rotator cuff arthropathy (n=265) and pseudopralysis with osteoarthritis (n=111). The mean follow-up was 40.3 months (range, 28-52 months). Active forward flexion, abduction, external rotation and internal rotation improved with a mean change of 47 to 82º, 43 to 80º, 8 to 39º and 0.6 to 2 points, respectively. Functional scores also improved from pre to postoperative assessment including the American Shoulder and Elbow (mean change, 20 to 50), Constant (mean change, 28 to 40), Simple Shoulder Test (mean change, 3 to 7) and visual analogue score (mean change, -2 to -5). Complication ranged from 0 to 20% and accounted 85 complications (29% aseptic loosening, 9% acromion fracture, 7% glenosphere dissociation, 6% instability, and 6% infection). Scapular notching from 0 to 30% and of those with scapular notching, 53% were grade I, 40% grade II, 7% grade III and 0% grade IV (Sirveaux-Nerot classification). Rate of patients undergoing revision shoulder arthroplasty varied from 0 to 13%.
The RSA with a lateralized glenosphere implant improves active shoulder motion and clinical and functional outcomes in selected patients with rotator cuff arthropathy or pseudoparalysis. These results seem comparable to those previously reported for Grammont design implants, but with the newsworthy lower rate of scapular notching.