Dialing the glenosphere eccentricity posteriorly to optimize range of motion in reverse shoulder arthroplasty
Background: Friction is the primary cause of notching in reverse shoulder arthroplasty during internal, external rotation (IR/ER), and extension (EXT). To address notching, glenosphere eccentricity (ECC) was introduced. The primary objective of this study was to investigate different positions of gl...
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Elsevier
2025-01-01
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| Series: | JSES International |
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| Online Access: | http://www.sciencedirect.com/science/article/pii/S2666638324004006 |
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| author | Stefan Bauer, MD Arnaud Meylan, MD Jaad Mahlouly, MD Wei Shao, MD William G. Blakeney, MBBS, MSc, MS, FRACS |
| author_facet | Stefan Bauer, MD Arnaud Meylan, MD Jaad Mahlouly, MD Wei Shao, MD William G. Blakeney, MBBS, MSc, MS, FRACS |
| author_sort | Stefan Bauer, MD |
| collection | DOAJ |
| description | Background: Friction is the primary cause of notching in reverse shoulder arthroplasty during internal, external rotation (IR/ER), and extension (EXT). To address notching, glenosphere eccentricity (ECC) was introduced. The primary objective of this study was to investigate different positions of glenosphere ECC to determine whether there is an optimal position for impingement-free range of motion. Methods: In this computer model study, 10 female CTs were analyzed and EXT, ER, IR, and adduction simulated (18 models.) A 135° stem with a +10° liner (145°) was combined with a 25-mm standard/or +3-mm lateralized baseplate (BP) and a 36-mm +2-mm eccentric glenosphere in 4 ECC positions (50° posterior; 30° posterior; 30° anterior; 50° anterior) from the reference position 0° neutral (10 models). Additionally, a concentric 39-mm glenosphere was tested (+2 models). A 0° insert, 135° neck shaft angle (NSA), was tested with a 25-mm standard/or +3-mm BP for 3 configurations (30° posterior; neutral; 39 mm; +6 models). Results: Compared to the 0° neutral reference position, 30° posterior dialing improved the mean ER (group 145°: 40° vs. 38°, group 145° + 3: 51° vs. 49°, both P < .0001), and EXT (group 145°: 35° vs. 34°, P = .029, group 145° + 3: 57° vs. 47°, P = .046, but at the expense of IR (group 145°: 83° vs. 87°, group 145° + 3: 87° vs. 91°, both P < .0001). The position 30° anterior increased IR (group 145°: 90° vs. 87°, group 145° + 3: 94° vs. 91°, both P < .0001) at the expense of ER (group 145°: 33° vs. 38°, group 145° + 3: 44° vs. 49°, both P < .0001) and EXT (group 145°: 24° vs. 34°, P = .055, group 145° +3 mm: 39° vs. 47°, P = .0042). For group 145°, 0° neutral was the best position for combined EXT + IR (121°) compared to 30° posterior/30° anterior/39 mm/50° posterior/50° anterior (118°/113°/118°/113°/110°, P < .0001/P = .15/P = .076/P < .0001/P = .074, respectively) and IR + ER (125° vs. 122°/123°/123°/118°/119°/, P < .001/P = .0028/P = .7/P < .0001/P = .0001, respectively). Lateralization, but most effectively a 135° NSA improved combined EXT + IR + ER + adduction (group 145°: 179° vs. group 135°: 243°, group 145° + 3: 215° vs. group 135° + 3: 276°, P = .0019/P = .00019, respectively). The influence of position 0°neutral or 30°posterior became marginal with a 135°NSA. Conclusion: Posterior dialing of the ECC increases EXT and ER but at the expense of IR. Lateralization, but most effectively a 135° NSA, increase impingement-free motion. A larger noneccentric glenosphere on the same BP is a safe all-round solution to prevent ECC positioning outliers. |
| format | Article |
| id | doaj-art-6ce820b05e7b45e186b8edf89c6de64d |
| institution | Kabale University |
| issn | 2666-6383 |
| language | English |
| publishDate | 2025-01-01 |
| publisher | Elsevier |
| record_format | Article |
| series | JSES International |
| spelling | doaj-art-6ce820b05e7b45e186b8edf89c6de64d2025-01-12T05:26:02ZengElsevierJSES International2666-63832025-01-0191181187Dialing the glenosphere eccentricity posteriorly to optimize range of motion in reverse shoulder arthroplastyStefan Bauer, MD0Arnaud Meylan, MD1Jaad Mahlouly, MD2Wei Shao, MD3William G. Blakeney, MBBS, MSc, MS, FRACS4Centre de l'Épaule et du Membre Supérieur, Ensemple Hospitalier de la Côte, Morges, Switzerland; School of Surgery, University of Western Australia, Perth, AustraliaCentre de l'Épaule et du Membre Supérieur, Ensemple Hospitalier de la Côte, Morges, SwitzerlandCentre de l'Épaule et du Membre Supérieur, Ensemple Hospitalier de la Côte, Morges, SwitzerlandCentre de l'Épaule et du Membre Supérieur, Ensemple Hospitalier de la Côte, Morges, SwitzerlandSchool of Surgery, University of Western Australia, Perth, Australia; Orthopaedic Department, Royal Perth Hospital, Perth, Australia; Corresponding author: William G Blakeney, MBBS, MSc, MS, FRACS, Department of Orthopaedics, Royal Perth Hospital, Victoria Avenue Perth, WA 6000, Australia.Background: Friction is the primary cause of notching in reverse shoulder arthroplasty during internal, external rotation (IR/ER), and extension (EXT). To address notching, glenosphere eccentricity (ECC) was introduced. The primary objective of this study was to investigate different positions of glenosphere ECC to determine whether there is an optimal position for impingement-free range of motion. Methods: In this computer model study, 10 female CTs were analyzed and EXT, ER, IR, and adduction simulated (18 models.) A 135° stem with a +10° liner (145°) was combined with a 25-mm standard/or +3-mm lateralized baseplate (BP) and a 36-mm +2-mm eccentric glenosphere in 4 ECC positions (50° posterior; 30° posterior; 30° anterior; 50° anterior) from the reference position 0° neutral (10 models). Additionally, a concentric 39-mm glenosphere was tested (+2 models). A 0° insert, 135° neck shaft angle (NSA), was tested with a 25-mm standard/or +3-mm BP for 3 configurations (30° posterior; neutral; 39 mm; +6 models). Results: Compared to the 0° neutral reference position, 30° posterior dialing improved the mean ER (group 145°: 40° vs. 38°, group 145° + 3: 51° vs. 49°, both P < .0001), and EXT (group 145°: 35° vs. 34°, P = .029, group 145° + 3: 57° vs. 47°, P = .046, but at the expense of IR (group 145°: 83° vs. 87°, group 145° + 3: 87° vs. 91°, both P < .0001). The position 30° anterior increased IR (group 145°: 90° vs. 87°, group 145° + 3: 94° vs. 91°, both P < .0001) at the expense of ER (group 145°: 33° vs. 38°, group 145° + 3: 44° vs. 49°, both P < .0001) and EXT (group 145°: 24° vs. 34°, P = .055, group 145° +3 mm: 39° vs. 47°, P = .0042). For group 145°, 0° neutral was the best position for combined EXT + IR (121°) compared to 30° posterior/30° anterior/39 mm/50° posterior/50° anterior (118°/113°/118°/113°/110°, P < .0001/P = .15/P = .076/P < .0001/P = .074, respectively) and IR + ER (125° vs. 122°/123°/123°/118°/119°/, P < .001/P = .0028/P = .7/P < .0001/P = .0001, respectively). Lateralization, but most effectively a 135° NSA improved combined EXT + IR + ER + adduction (group 145°: 179° vs. group 135°: 243°, group 145° + 3: 215° vs. group 135° + 3: 276°, P = .0019/P = .00019, respectively). The influence of position 0°neutral or 30°posterior became marginal with a 135°NSA. Conclusion: Posterior dialing of the ECC increases EXT and ER but at the expense of IR. Lateralization, but most effectively a 135° NSA, increase impingement-free motion. A larger noneccentric glenosphere on the same BP is a safe all-round solution to prevent ECC positioning outliers.http://www.sciencedirect.com/science/article/pii/S2666638324004006GlenosphereEccentricityReverse shoulder arthroplastyRange of motionImpingementNotching |
| spellingShingle | Stefan Bauer, MD Arnaud Meylan, MD Jaad Mahlouly, MD Wei Shao, MD William G. Blakeney, MBBS, MSc, MS, FRACS Dialing the glenosphere eccentricity posteriorly to optimize range of motion in reverse shoulder arthroplasty JSES International Glenosphere Eccentricity Reverse shoulder arthroplasty Range of motion Impingement Notching |
| title | Dialing the glenosphere eccentricity posteriorly to optimize range of motion in reverse shoulder arthroplasty |
| title_full | Dialing the glenosphere eccentricity posteriorly to optimize range of motion in reverse shoulder arthroplasty |
| title_fullStr | Dialing the glenosphere eccentricity posteriorly to optimize range of motion in reverse shoulder arthroplasty |
| title_full_unstemmed | Dialing the glenosphere eccentricity posteriorly to optimize range of motion in reverse shoulder arthroplasty |
| title_short | Dialing the glenosphere eccentricity posteriorly to optimize range of motion in reverse shoulder arthroplasty |
| title_sort | dialing the glenosphere eccentricity posteriorly to optimize range of motion in reverse shoulder arthroplasty |
| topic | Glenosphere Eccentricity Reverse shoulder arthroplasty Range of motion Impingement Notching |
| url | http://www.sciencedirect.com/science/article/pii/S2666638324004006 |
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