Alexandre Lädermann1,2,3,4, Patrick J Denard5,6, Philippe Collin7, Olivia Zbinden8, Joe Chih-Hao Chiu9, Pascal Boileau10, Flora Olivier11, Gilles Walch12. 1. Division of Orthopaedics and Trauma Surgery, La Tour Hospital, Meyrin, Switzerland. 2. Faculty of Medicine, University of Geneva, Geneva, Switzerland. 3. Division of Orthopaedics and Trauma Surgery, Department of Surgery, Geneva University Hospitals, Geneva, Switzerland. 4. Division of Orthopaedics and Trauma Surgery, Hirslanden Clinique La Colline, Geneva, Switzerland. 5. Southern Oregon Orthopedics, Medford, OR, USA. 6. Department of Orthopaedics and Rehabilitation, Oregon Health & Science University, Portland, OR, USA. 7. Centre Hospitalier Privé Saint-Grégoire (Vivalto Santé), Saint-Grégoire, France. 8. Service of Orthopedics and Traumatology, Lausanne University Hospital, Lausanne, Switzerland. 9. Department of Orthopaedic Sports Medicine, Chang Gung Memorial Hospital, Taoyuan City, Taiwan. 10. iULS (Institut Universitaire Locomoteur et du Sport), Hôpital Pasteur 2, University Côte d'Azur, Nice, France. 11. ReSurg SA, Rue Saint-Jean 22, 1260, Nyon, Switzerland. journals@resurg.com. 12. Centre Orthopédique Santy, Hôpital Privé Jean Mermoz Ramsay GDS, Lyon, France.
Abstract
PURPOSE: To determine how different combinations of humeral stem and glenosphere designs for reverse shoulder arthroplasty (RSA) influence range of motion (ROM) and muscle elongation. METHODS: A computed tomography scan of a non-pathologic shoulder was used to simulate all shoulder motions, and thereby compare the ROM and rotator cuff muscle lengths of the native shoulder versus 30 combinations of humeral components (1 inlay straight stem with 155° inclination and five onlay curved stems with 135°, 145° or 155° inclinations, using concentric, medialized or lateralized trays) and glenospheres (standard, large, lateralized, inferior eccentric and bony increased-offset (BIO-RSA)). RESULTS: Only five of the 30 combinations restored ≥ 50% of the native ROM in all directions: the 145° onlay stem (concentric tray) combined with lateralized or inferior eccentric glenospheres and the 145° stem (lateralized tray) combined with either a large, lateralized or inferior eccentric glenosphere. Lengthening of the supraspinatus and infraspinatus, observed for all configurations, was greatest using onlay stems (7-30%) and BIO-RSA glenospheres (13-31%). Subscapularis lengthening was observed for onlay stems combined with BIO-RSA glenospheres (5-9%), while excessive subscapularis shortening was observed for the inlay stem combined with all glenospheres except the BIO-RSA design (> 15%). CONCLUSIONS: The authors suggest implanting 145° onlay stems, with concentric or lateralized trays, together with lateralized or inferior eccentric glenospheres.
PURPOSE: To determine how different combinations of humeral stem and glenosphere designs for reverse shoulder arthroplasty (RSA) influence range of motion (ROM) and muscle elongation. METHODS: A computed tomography scan of a non-pathologic shoulder was used to simulate all shoulder motions, and thereby compare the ROM and rotator cuff muscle lengths of the native shoulder versus 30 combinations of humeral components (1 inlay straight stem with 155° inclination and five onlay curved stems with 135°, 145° or 155° inclinations, using concentric, medialized or lateralized trays) and glenospheres (standard, large, lateralized, inferior eccentric and bony increased-offset (BIO-RSA)). RESULTS: Only five of the 30 combinations restored ≥ 50% of the native ROM in all directions: the 145° onlay stem (concentric tray) combined with lateralized or inferior eccentric glenospheres and the 145° stem (lateralized tray) combined with either a large, lateralized or inferior eccentric glenosphere. Lengthening of the supraspinatus and infraspinatus, observed for all configurations, was greatest using onlay stems (7-30%) and BIO-RSA glenospheres (13-31%). Subscapularis lengthening was observed for onlay stems combined with BIO-RSA glenospheres (5-9%), while excessive subscapularis shortening was observed for the inlay stem combined with all glenospheres except the BIO-RSA design (> 15%). CONCLUSIONS: The authors suggest implanting 145° onlay stems, with concentric or lateralized trays, together with lateralized or inferior eccentric glenospheres.
Entities:
Keywords:
Glenoid and humeral offset; Glenosphere design; Humeral stem design; Impingement; Muscle length; Range of motion; Reverse total shoulder arthroplasty
Authors: Philipp Moroder; Manuel Urvoy; Patric Raiss; Jean-David Werthel; Doruk Akgün; Jean Chaoui; Paul Siegert Journal: Clin Orthop Relat Res Date: 2022-03-01 Impact factor: 4.755