Aims. The aim of this study was to report long-term clinical outcomes of a modern convertible metal-backed glenoid (MBG) in total shoulder arthroplasty (TSA). Methods. After a minimum of 15 years, a previously studied cohort of 35 patients who received a modern convertible MBG during the period 1996 to 2005 was contacted for clinical and radiological follow-up. At last follow-up, patients were evaluated radiologically and clinically according to the Constant Score, Simple Shoulder Test, and visual analogue scale for pain. Complications and revisions were recorded, and survival analysis was performed. Results. At the last follow-up, 20 patients were contacted. Of these, 15 patients had experienced at least one complication, and ten underwent revision surgery. The mean time to revision was 13.8 years (7 to 20). Cuff failure was the most common complication. Conversion to reverse shoulder arthroplasty, while maintaining the baseplate, was possible in five cases, with good results. In patients in whom the baseplate was removed, revision was performed significantly later (18.4 vs 11.1 years; p = 0.016). The general revision-free survival was 73% (95% CI 49.5 to 87.3) at 15 years and 38% (95% CI 11.8% to 64.3%) at 20 years, while MBG revision-free survival was 96.0% (95% CI 74.8% to 99.4%) at 15 years and 54% (95% CI 16.2% to 80.8%) at 20 years. Clinical scores showed a negative trend over time, although not statistically significant. Radiologically, polyethylene wear was observed in all cases and was complete in 12 out of 19 cases, and five glenoids were ‘at risk’ for loosening. Conclusion. At long-term follow-up, convertible MBG-TSA revealed a high rate of complications and revision surgery, mainly due to soft-tissue failure and polyethylene wear occurring with time. Prompt conversion to RSA maintaining the baseplate provided good results and a low complication rate. Radiological follow-up at about ten years is strictly recommended and, if metal-to-metal contact is observed, conversion to RSA is advisable. These results emphasize the need for continued research into improving TSA outcomes, especially in cases of MBG usage. Cite this article: Bone Jt Open 2025;6(1):82–92

Aims. Optimal glenoid positioning in reverse shoulder arthroplasty (RSA) is crucial to provide impingement-free range of motion (ROM). Lateralization and inclination correction are not yet systematically used. Using planning software, we simulated the most used glenoid implant positions. The primary goal was to determine the configuration that delivers the best theoretical impingement-free ROM. Methods. With the use of a 3D planning software (Blueprint) for RSA, 41 shoulders in 41 consecutive patients (17 males and 24 females; means age 73 years (SD 7)) undergoing RSA were planned. For the same anteroposterior positioning and retroversion of the glenoid implant, four different glenoid baseplate configurations were used on each shoulder to compare ROM: 1) no correction of the RSA angle and no lateralization (C-L-); 2) correction of the RSA angle with medialization by inferior reaming (C+M+); 3) correction of the RSA angle without lateralization by superior compensation (C+L-); and 4) correction of the RSA angle and additional lateralization (C+L+). The same humeral inlay implant and positioning were used on the humeral side for the four different glenoid configurations with a 3 mm symmetric 135° inclined polyethylene liner. Results. The configuration with lateralization and correction of the RSA angle (C+L+) led to better ROM in flexion, extension, adduction, and external rotation (p ≤ 0.001). Only internal rotation was not significantly different between groups (p = 0.388). The configuration where correction of the inclination was done by medialization (C+M+) led to the worst ROM in adduction, extension, abduction, flexion, and external rotation of the shoulder. Conclusion. Our software study shows that, when using a 135° inlay reversed humeral implant, correcting glenoid inclination (RSA angle 0°) and lateralizing the glenoid component by using an angled bony or metallic augment of 8 to 10 mm provides optimal impingement-free ROM. Cite this article: Bone Jt Open 2024;5(10):851–857

Aims

The liner design is a key determinant of the constraint of a reverse total shoulder arthroplasty (rTSA). The aim of this study was to compare the degree of constraint of rTSA liners between different implant systems.