Clinics in Shoulder and Elbow

Korean Shoulder and Elbow Society (대한견·주관절의학회)
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Implant selection for successful reverse total shoulder arthroplasty

  • Joo Han Oh (Department of Orthopedic Surgery, Seoul National University Bundang Hospital, Seoul National University College of Medicine) ;
  • Hyeon Jang Jeong (Department of Orthopedic Surgery, Seoul National University Bundang Hospital, Seoul National University College of Medicine) ;
  • Yoo-Sun Won (Department of Orthopedic Surgery, Seoul National University Bundang Hospital, Seoul National University College of Medicine)
  • Received : 2022.08.11
  • Accepted : 2022.10.03
  • Published : 2023.03.01
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Abstract

Reverse total shoulder arthroplasty (RTSA) emerged as a new concept of arthroplasty that does not restore normal anatomy but does restore function. It enables the function of the torn rotator cuff to be performed by the deltoid and shows encouraging clinical outcomes. Since its introduction, various modifications have been designed to improve the outcome of the RTSA. From the original cemented baseplate with peg or keel, a cementless baseplate was designed that could be fixed with central and peripheral screws. In addition, a modular-type glenoid component enabled easier revision options. For the humeral component, the initial design was an inlay type of long stem with cemented fixation. However, loss of bone stock from the cemented stem hindered revision surgery. Therefore, a cementless design was introduced with a firm metaphyseal fixation. Furthermore, to prevent complications such as scapular notching, the concept of lateralization emerged. Lateralization helped to maintain normal shoulder contour and better rotator cuff function for improved external/internal rotation power, but excessive lateralization yielded problems such as subacromial notching. Therefore, for patients with pseudoparalysis or with risk of subacromial notching, a medial eccentric tray option can be used for distalization and reduced lateralization of the center of rotation. In summary, it is important that surgeons understand the characteristics of each implant in the various options for RTSA. Furthermore, through preoperative evaluation of patients, surgeons can choose the implant option that will lead to the best outcomes after RTSA.

Keywords

References

  1. Jonsson EO, Ekholm C, Salomonsson B, Demir Y, Olerud P; Collaborators in the SAPF Study Group. Reverse total shoulder arthroplasty provides better shoulder function than hemiarthroplasty for displaced 3- and 4-part proximal humeral fractures in patients aged 70 years or older: a multicenter randomized controlled trial. J Shoulder Elbow Surg 2021;30:994-1006.  https://doi.org/10.1016/j.jse.2020.10.037
  2. Rugg CM, Gallo RA, Craig EV, Feeley BT. The pathogenesis and management of cuff tear arthropathy. J Shoulder Elbow Surg 2018;27:2271-83.  https://doi.org/10.1016/j.jse.2018.07.020
  3. Harman M, Frankle M, Vasey M, Banks S. Initial glenoid component fixation in "reverse" total shoulder arthroplasty: a biomechanical evaluation. J Shoulder Elbow Surg 2005;14(1 Suppl S):162S-167S.  https://doi.org/10.1016/j.jse.2004.09.030
  4. Grammont PM, Baulot E. Delta shoulder prosthesis for rotator cuff rupture. Orthopedics 1993;16:65-8.  https://doi.org/10.3928/0147-7447-19930101-11
  5. Monir JG, Abeyewardene D, King JJ, Wright TW, Schoch BS. Reverse shoulder arthroplasty in patients younger than 65 years, minimum 5-year follow-up. J Shoulder Elbow Surg 2020;29:e215-21.  https://doi.org/10.1016/j.jse.2019.10.028
  6. Kim H, Kim CH, Kim M, et al. Is reverse total shoulder arthroplasty (rTSA) more advantageous than anatomic TSA (aTSA) for osteoarthritis with intact cuff tendon? A systematic review and meta-analysis. J Orthop Traumatol 2022;23:3. 
  7. Dickerson P, Pill SG, Longstaffe R, Shanley E, Thigpen CA, Kissenberth MJ. Systematic review of reversing pseudoparalysis of the shoulder due to massive, irreparable rotator cuff tears. J Shoulder Elbow Surg 2020;29(7S):S87-91.  https://doi.org/10.1016/j.jse.2020.04.039
  8. Kazley JM, Cole KP, Desai KJ, Zonshayn S, Morse AS, Banerjee S. Prostheses for reverse total shoulder arthroplasty. Expert Rev Med Devices 2019;16:107-18.  https://doi.org/10.1080/17434440.2019.1568237
  9. Crum RJ, de Sa DL, Su FL, Lesniak BP, Lin A. Decreased complication profile and improved clinical outcomes of primary reverse total shoulder arthroplasty after 2010: a systematic review. Shoulder Elbow 2021;13:154-67.  https://doi.org/10.1177/1758573219852977
  10. Cho SH, Lee HJ, Aldhafian OR, Kim YS. Comparison of lateralized versus medialized reverse total shoulder arthroplasty: a systematic review and meta-analysis. Orthop J Sports Med 2022;10:23259671211063922. 
  11. Youn SM, Lee HS, Rhee SM, Rhee YG. Medialized vs. lateralized humeral implant in reverse total shoulder arthroplasty: the comparison of outcomes in pseudoparalysis with massive rotator cuff tear. J Shoulder Elbow Surg 2022;31:736-46.  https://doi.org/10.1016/j.jse.2021.08.011
  12. Callegari J, Haidamous G, Ladermann A, Phillips C, Tracy S, Denard P. Factors influencing appropriate implant selection and position in reverse total shoulder arthroplasty. Orthop Clin North Am 2021;52:157-66.  https://doi.org/10.1016/j.ocl.2020.12.006
  13. Nyffeler RW, Altioklar B, Bissig P. Causes of acromion and scapular spine fractures following reverse shoulder arthroplasty: a retrospective analysis and literature review. Int Orthop 2020;44:2673-81.  https://doi.org/10.1007/s00264-020-04813-5
  14. Cabezas AF, Krebes K, Hussey MM, et al. Morphologic variability of the shoulder between the populations of North American and East Asian. Clin Orthop Surg 2016;8:280-7.  https://doi.org/10.4055/cios.2016.8.3.280
  15. Jeong HJ, Jeong MG, Kim SW, et al. Optimal insertion site of glenoid baseplate in reverse total shoulder arthroplasty: anatomical simulation using three dimensional image processing software. Int Orthop 2021;45:3171-7.  https://doi.org/10.1007/s00264-021-05235-7
  16. Oh JH, Lee S, Rhee SM, Jeong HJ, Yoo JC. Rationale for small glenoid baseplate: position of central cage within glenoid vault (Exactech® Equinoxe® Reverse System). Clin Shoulder Elb 2019;22:24-8.  https://doi.org/10.5397/cise.2019.22.1.24
  17. Jha SC, Fukuta S, Wada K, et al. Optimizing baseplate position in reverse total shoulder arthroplasty in small-sized Japanese females: technical notes and literature review. J Med Invest 2016;63:8-14.  https://doi.org/10.2152/jmi.63.8
  18. Mourad W, Wiater JM, Wiater BP, Martusiewicz A. Baseplate options for reverse total shoulder arthroplasty. Curr Rev Musculoskelet Med 2020;13:769-75.  https://doi.org/10.1007/s12178-020-09677-1
  19. Roche C, DiGeorgio C, Yegres J, et al. Impact of screw length and screw quantity on reverse total shoulder arthroplasty glenoid fixation for 2 different sizes of glenoid baseplates. JSES Open Access 2019;3:296-303.  https://doi.org/10.1016/j.jses.2019.08.006
  20. Rhee SM, Lee JD, Park YB, Yoo JC, Oh JH. Prognostic radiological factors affecting clinical outcomes of reverse shoulder arthroplasty in the Korean population. Clin Orthop Surg 2019;11:112-9.  https://doi.org/10.4055/cios.2019.11.1.112
  21. Stephens BF, Hebert CT, Azar FM, Mihalko WM, Throckmorton TW. Optimal baseplate rotational alignment for locking-screw fixation in reverse total shoulder arthroplasty: a three-dimensional computer-aided design study. J Shoulder Elbow Surg 2015;24:1367-71.  https://doi.org/10.1016/j.jse.2015.01.012
  22. Li J, Zhou J, Wang D, Li D, Zhang W. Applied anatomical study on suprascapular nerve protection in reverse total shoulder arthroplasty. J Orthop Surg Res 2020;15:524. 
  23. Frank JK, Siegert P, Plachel F, Heuberer PR, Huber S, Schanda JE. The evolution of reverse total shoulder arthroplasty-from the first steps to novel implant designs and surgical techniques. J Clin Med 2022;11:1512. 
  24. Denard PJ, Werner BC, Gobezie R, Tokish JM, Kissenberth MJ, Lederman E. Lower rates of radiolucency with a hybrid all-polyethylene pegged glenoid component compared to a completely cemented pegged glenoid component. Semin Arthroplasty 2020;30:56-62.  https://doi.org/10.1053/j.sart.2020.05.002
  25. Bodendorfer BM, Loughran GJ, Looney AM, et al. Short-term outcomes of reverse shoulder arthroplasty using a custom baseplate for severe glenoid deficiency. J Shoulder Elbow Surg 2021;30:1060-7.  https://doi.org/10.1016/j.jse.2020.08.002
  26. Hartzler RU, Denard PJ, Griffin JW, Werner BC, Romeo AA. Surgeon acceptance of an initial 3D glenoid preoperative plan: rates and risk factors. J Shoulder Elbow Surg 2021;30:787-94.  https://doi.org/10.1016/j.jse.2020.06.032
  27. Jones RB, Wright TW, Roche CP. Bone grafting the glenoid versus use of augmented glenoid baseplates with reverse shoulder arthroplasty. Bull Hosp Jt Dis (2013) 2015;73 Suppl 1:S129-35. 
  28. Virk M, Yip M, Liuzza L, et al. Clinical and radiographic outcomes with a posteriorly augmented glenoid for Walch B2, B3, and C glenoids in reverse total shoulder arthroplasty. J Shoulder Elbow Surg 2020;29:e196-204.  https://doi.org/10.1016/j.jse.2019.09.031
  29. Rangarajan R, Blout CK, Patel VV, Bastian SA, Lee BK, Itamura JM. Early results of reverse total shoulder arthroplasty using a patient-matched glenoid implant for severe glenoid bone deficiency. J Shoulder Elbow Surg 2020;29(7S):S139-48.  https://doi.org/10.1016/j.jse.2020.04.024
  30. Paisley KC, Kraeutler MJ, Lazarus MD, Ramsey ML, Williams GR, Smith MJ. Relationship of scapular neck length to scapular notching after reverse total shoulder arthroplasty by use of plain radiographs. J Shoulder Elbow Surg 2014;23:882-7.  https://doi.org/10.1016/j.jse.2013.09.003
  31. Duethman NC, Aibinder WR, Nguyen NT, Sanchez-Sotelo J. The influence of glenoid component position on scapular notching: a detailed radiographic analysis at midterm follow-up. JSES Int 2020;4:144-50.  https://doi.org/10.1016/j.jses.2019.11.004
  32. Edwards TB, Trappey GJ, Riley C, O'Connor DP, Elkousy HA, Gartsman GM. Inferior tilt of the glenoid component does not decrease scapular notching in reverse shoulder arthroplasty: results of a prospective randomized study. J Shoulder Elbow Surg 2012;21:641-6.  https://doi.org/10.1016/j.jse.2011.08.057
  33. Jang YH, Lee JH, Kim SH. Effect of scapular notching on clinical outcomes after reverse total shoulder arthroplasty. Bone Joint J 2020;102:1438-45.  https://doi.org/10.1302/0301-620X.102B11.BJJ-2020-0449.R1
  34. Collotte P, Erickson J, Vieira TD, Domos P, Walch G. Clinical and radiologic outcomes of eccentric glenosphere versus concentric glenosphere in reverse shoulder arthroplasty. J Shoulder Elbow Surg 2021;30:1899-906.  https://doi.org/10.1016/j.jse.2020.10.032
  35. Nolte PC, Miles JW, Tanghe KK, et al. The effect of glenosphere lateralization and inferiorization on deltoid force in reverse total shoulder arthroplasty. J Shoulder Elbow Surg 2021;30:1817-26.  https://doi.org/10.1016/j.jse.2020.10.038
  36. Patel M, Martin JR, Campbell DH, Fernandes RR, Amini MH. Inferior tilt of the glenoid leads to medialization and increases impingement on the scapular neck in reverse shoulder arthroplasty. J Shoulder Elbow Surg 2021;30:1273-81.  https://doi.org/10.1016/j.jse.2020.09.023
  37. Poon PC, Chou J, Young SW, Astley T. A comparison of concentric and eccentric glenospheres in reverse shoulder arthroplasty: a randomized controlled trial. J Bone Joint Surg Am 2014;96:e138. 
  38. de Wilde LF, Poncet D, Middernacht B, Ekelund A. Prosthetic overhang is the most effective way to prevent scapular conflict in a reverse total shoulder prosthesis. Acta Orthop 2010;81:719-26.  https://doi.org/10.3109/17453674.2010.538354
  39. Chou J, Malak SF, Anderson IA, Astley T, Poon PC. Biomechanical evaluation of different designs of glenospheres in the SMR reverse total shoulder prosthesis: range of motion and risk of scapular notching. J Shoulder Elbow Surg 2009;18:354-9.  https://doi.org/10.1016/j.jse.2009.01.015
  40. Collotte P, Bercik M, Vieira TD, Walch G. Long-term reverse total shoulder arthroplasty outcomes: the effect of the inferior shifting of glenoid component fixation. Clin Orthop Surg 2021;13:505-12.  https://doi.org/10.4055/cios20245
  41. Routman HD, Simovitch RW, Wright TW, Flurin PH, Zuckerman JD, Roche CP. Acromial and scapular fractures after reverse total shoulder arthroplasty with a medialized glenoid and lateralized humeral implant: an analysis of outcomes and risk factors. J Bone Joint Surg Am 2020;102:1724-33.  https://doi.org/10.2106/JBJS.19.00724
  42. Schoch BS, Taba H, Aibinder W, King JJ, Wright TW. Effect of reverse shoulder arthroplasty lateralization design on scapular notching: a single-surgeon experience. Orthopedics 2020;43:e585-91.  https://doi.org/10.3928/01477447-20200812-10
  43. Kennon JC, Songy C, Bartels D, et al. Primary reverse shoulder arthroplasty: how did medialized and glenoid-based lateralized style prostheses compare at 10 years. J Shoulder Elbow Surg 2020;29(7S):S23-31.  https://doi.org/10.1016/j.jse.2019.11.004
  44. Denard PJ, Lederman E, Parsons BO, Romeo AA. Finite element analysis of glenoid-sided lateralization in reverse shoulder arthroplasty. J Orthop Res 2017;35:1548-55.  https://doi.org/10.1002/jor.23394
  45. Giuseffi SA, Streubel P, Sperling J, Sanchez-Sotelo J. Short-stem uncemented primary reverse shoulder arthroplasty: clinical and radiological outcomes. Bone Joint J 2014;96:526-9.  https://doi.org/10.1302/0301-620X.96B3.32702
  46. Kerrigan AM, Reeves J, Langohr GD, Johnson JA, Athwal GS. Reverse shoulder arthroplasty glenoid lateralization influences scapular spine strains. Shoulder Elbow 2021;13:610-9.  https://doi.org/10.1177/1758573220935567
  47. Muller AM, Born M, Jung C, et al. Glenosphere size in reverse shoulder arthroplasty: is larger better for external rotation and abduction strength. J Shoulder Elbow Surg 2018;27:44-52.  https://doi.org/10.1016/j.jse.2017.06.002
  48. Roche CP. Reverse shoulder arthroplasty biomechanics. J Funct Morphol Kinesiol 2022;7:13. 
  49. Boileau P, Morin-Salvo N, Gauci MO, et al. Angled BIO-RSA (bony-increased offset-reverse shoulder arthroplasty): a solution for the management of glenoid bone loss and erosion. J Shoulder Elbow Surg 2017;26:2133-42.  https://doi.org/10.1016/j.jse.2017.05.024
  50. Kirzner N, Paul E, Moaveni A. Reverse shoulder arthroplasty vs BIO-RSA: clinical and radiographic outcomes at short term follow-up. J Orthop Surg Res 2018;13:256. 
  51. Akhtar A, Ng CY. Cement extrusion and radial nerve palsy during revision shoulder and elbow arthroplasty: beware of the cortical breach. J Clin Orthop Trauma 2021;16:226-9.  https://doi.org/10.1016/j.jcot.2021.02.013
  52. Wiater JM, Moravek JE Jr, Budge MD, Koueiter DM, Marcantonio D, Wiater BP. Clinical and radiographic results of cementless reverse total shoulder arthroplasty: a comparative study with 2 to 5 years of follow-up. J Shoulder Elbow Surg 2014;23:1208-14.  https://doi.org/10.1016/j.jse.2013.11.032
  53. Denard PJ, Noyes MP, Walker JB, et al. Proximal stress shielding is decreased with a short stem compared with a traditional-length stem in total shoulder arthroplasty. J Shoulder Elbow Surg 2018;27:53-8.  https://doi.org/10.1016/j.jse.2017.06.042
  54. Erickson BJ, Denard PJ, Griffin JW, Gobezie R, Lederman E, Werner BC. Initial and 1-year radiographic comparison of reverse total shoulder arthroplasty with a short versus standard length stem. J Am Acad Orthop Surg 2022;30:e968-78.  https://doi.org/10.5435/JAAOS-D-21-01032
  55. Wagner ER, Statz JM, Houdek MT, Cofield RH, Sanchez-Sotelo J, Sperling JW. Use of a shorter humeral stem in revision reverse shoulder arthroplasty. J Shoulder Elbow Surg 2017;26:1454-61.  https://doi.org/10.1016/j.jse.2017.01.016
  56. Erickson BJ, Chalmers PN, Denard PJ, Gobezie R, Romeo AA, Lederman ES. Current state of short-stem implants in total shoulder arthroplasty: a systematic review of the literature. JSES Int 2020;4:114-9.  https://doi.org/10.1016/j.jses.2019.10.112
  57. Abdic S, Athwal GS, Wittmann T, Walch G, Raiss P. Short stem humeral components in reverse shoulder arthroplasty: stem alignment influences the neck-shaft angle. Arch Orthop Trauma Surg 2021;141:183-8.  https://doi.org/10.1007/s00402-020-03424-4
  58. Upfill-Brown A, Satariano N, Feeley B. Stemless shoulder arthroplasty: review of short and medium-term results. JSES Open Access 2019;3:154-61.  https://doi.org/10.1016/j.jses.2019.07.008
  59. Romeo AA, Erickson BJ, Costouros J, et al. Eclipse stemless shoulder prosthesis vs. Univers II shoulder prosthesis: a multicenter, prospective randomized controlled trial. J Shoulder Elbow Surg 2020;29:2200-12.  https://doi.org/10.1016/j.jse.2020.07.004
  60. Kostretzis L, Konstantinou P, Pinto I, Shahin M, Ditsios K, Papadopoulos P. Stemless reverse total shoulder arthroplasty: a systematic review of contemporary literature. Musculoskelet Surg 2021;105:209-24.  https://doi.org/10.1007/s12306-021-00710-1
  61. Liu EY, Kord D, Yee NJ, et al. Stemless reverse total shoulder arthroplasty: a systematic review of short- and mid-term results. Shoulder Elbow 2021;13:482-91.  https://doi.org/10.1177/17585732211013356
  62. Magosch P, Lichtenberg S, Habermeyer P. Survival of stemless humeral head replacement in anatomic shoulder arthroplasty: a prospective study. J Shoulder Elbow Surg 2021;30:e343-55.  https://doi.org/10.1016/j.jse.2020.09.034
  63. Lewicki KA, Martin AJ, Bell JE, Van Citters DW. Fatigue failure of reverse shoulder humeral tray components of a single design. J Shoulder Elbow Surg 2016;25:1288-96.  https://doi.org/10.1016/j.jse.2015.12.021
  64. Kozak T, Bauer S, Walch G, Al-Karawi S, Blakeney W. An update on reverse total shoulder arthroplasty: current indications, new designs, same old problems. EFORT Open Rev 2021;6:189-201.  https://doi.org/10.1302/2058-5241.6.200085
  65. Gulotta LV, Choi D, Marinello P, et al. Humeral component retroversion in reverse total shoulder arthroplasty: a biomechanical study. J Shoulder Elbow Surg 2012;21:1121-7.  https://doi.org/10.1016/j.jse.2011.07.027
  66. Oh JH, Sharma N, Rhee SM, Park JH. Do individualized humeral retroversion and subscapularis repair affect the clinical outcomes of reverse total shoulder arthroplasty. J Shoulder Elbow Surg 2020;29:821-9.  https://doi.org/10.1016/j.jse.2019.08.016
  67. Stephenson DR, Oh JH, McGarry MH, Rick Hatch GF 3rd, Lee TQ. Effect of humeral component version on impingement in reverse total shoulder arthroplasty. J Shoulder Elbow Surg 2011;20:652-8.  https://doi.org/10.1016/j.jse.2010.08.020
  68. Aleem AW, Feeley BT, Austin LS, et al. Effect of humeral component version on outcomes in reverse shoulder arthroplasty. Orthopedics 2017;40:179-86. https://doi.org/10.3928/01477447-20170117-04
  69. Jassim SS, Ernstbrunner L, Ek ET. Does humeral component version affect range of motion and clinical outcomes in reverse total shoulder arthroplasty? A systematic review. J Clin Med 2021;10:5745. 
  70. Kontaxis A, Chen X, Berhouet J, et al. Humeral version in reverse shoulder arthroplasty affects impingement in activities of daily living. J Shoulder Elbow Surg 2017;26:1073-82.  https://doi.org/10.1016/j.jse.2016.11.052
  71. Oh JH, Kim W, Cayetano AA Jr. Measurement methods for humeral retroversion using two-dimensional computed tomography scans: which is most concordant with the standard method. Clin Orthop Surg 2017;9:223-31.  https://doi.org/10.4055/cios.2017.9.2.223
  72. Ladermann A, Denard PJ, Boileau P, et al. Effect of humeral stem design on humeral position and range of motion in reverse shoulder arthroplasty. Int Orthop 2015;39:2205-13.  https://doi.org/10.1007/s00264-015-2984-3
  73. Chan K, Langohr GD, Mahaffy M, Johnson JA, Athwal GS. Does humeral component lateralization in reverse shoulder arthroplasty affect rotator cuff torque? Evaluation in a cadaver model. Clin Orthop Relat Res 2017;475:2564-71.  https://doi.org/10.1007/s11999-017-5413-7
  74. Merolla G, Walch G, Ascione F, et al. Grammont humeral design versus onlay curved-stem reverse shoulder arthroplasty: comparison of clinical and radiographic outcomes with minimum 2-year follow-up. J Shoulder Elbow Surg 2018;27:701-10.  https://doi.org/10.1016/j.jse.2017.10.016
  75. Keener JD, Chalmers PN, Yamaguchi K. The humeral implant in shoulder arthroplasty. J Am Acad Orthop Surg 2017;25:427-38.  https://doi.org/10.5435/JAAOS-D-15-00682
  76. Gutierrez S, Comiskey CA 4th, Luo ZP, Pupello DR, Frankle MA. Range of impingement-free abduction and adduction deficit after reverse shoulder arthroplasty: hierarchy of surgical and implant-design-related factors. J Bone Joint Surg Am 2008;90:2606-15.  https://doi.org/10.2106/JBJS.H.00012
  77. Langohr GD, Willing R, Medley JB, Athwal GS, Johnson JA. Contact mechanics of reverse total shoulder arthroplasty during abduction: the effect of neck-shaft angle, humeral cup depth, and glenosphere diameter. J Shoulder Elbow Surg 2016;25:589-97.  https://doi.org/10.1016/j.jse.2015.09.024
  78. Giles JW, Langohr GD, Johnson JA, Athwal GS. Implant design variations in reverse total shoulder arthroplasty influence the required deltoid force and resultant joint load. Clin Orthop Relat Res 2015;473:3615-26.  https://doi.org/10.1007/s11999-015-4526-0
  79. Kim SC, Kim IS, Jang MC, Yoo JC. Complications of reverse shoulder arthroplasty: a concise review. Clin Shoulder Elb 2021;24:42-52.  https://doi.org/10.5397/cise.2021.00066
  80. Bacle G, Nove-Josserand L, Garaud P, Walch G. Long-term outcomes of reverse total shoulder arthroplasty: a follow-up of a previous study. J Bone Joint Surg Am 2017;99:454-61.  https://doi.org/10.2106/JBJS.16.00223
  81. Ernstbrunner L, Andronic O, Grubhofer F, Camenzind RS, Wieser K, Gerber C. Long-term results of reverse total shoulder arthroplasty for rotator cuff dysfunction: a systematic review of longitudinal outcomes. J Shoulder Elbow Surg 2019;28:774-81.  https://doi.org/10.1016/j.jse.2018.10.005
  82. Werthel JD, Walch G, Vegehan E, Deransart P, Sanchez-Sotelo J, Valenti P. Lateralization in reverse shoulder arthroplasty: a descriptive analysis of different implants in current practice. Int Orthop 2019;43:2349-60.  https://doi.org/10.1007/s00264-019-04365-3
  83. Greiner S, Schmidt C, Konig C, Perka C, Herrmann S. Lateralized reverse shoulder arthroplasty maintains rotational function of the remaining rotator cuff. Clin Orthop Relat Res 2013;471:940-6.  https://doi.org/10.1007/s11999-012-2692-x
  84. Nelson R, Lowe JT, Lawler SM, Fitzgerald M, Mantell MT, Jawa A. Lateralized center of rotation and lower neck-shaft angle are associated with lower rates of scapular notching and heterotopic ossification and improved pain for reverse shoulder arthroplasty at 1 year. Orthopedics 2018;41:230-6.  https://doi.org/10.3928/01477447-20180613-01
  85. Jeon YD, Yoon JY, Jeong HJ, et al. Significance of the acromiohumeral distance on stress radiography for predicting healing and function after arthroscopic repair of massive rotator cuff tears. J Shoulder Elbow Surg 2021;30:e471-81.  https://doi.org/10.1016/j.jse.2020.10.029
  86. Kwon J, Kim SH, Lee YH, Kim TI, Oh JH. The Rotator Cuff Healing Index: a new scoring system to predict rotator cuff healing after surgical repair. Am J Sports Med 2019;47:173-80. https://doi.org/10.1177/0363546518810763