An Analysis of Planned Inclination Correction by Reaming in Reverse Total Shoulder Arthroplasty

Matthew T Glazier ; Ryan Madden; Amanda Strickland; Robert Hartzler

Abstract

Background: The optimal inclination of the glenoid component in reverse total shoulder arthroplasty (RSA) is debated; however, an inferiorly tilted or neutral glenoid baseplate typically requires corrective reaming, structural grafting, or an augmented baseplate. Significant corrective reaming of the inferior glenoid has been theorized to result in medialization, a shortened scapular neck, and impingement. Few reports have described the relationship between the amount of reaming and factors such as degrees of inclination correction, indication for RSA, and patient demographics.Purpose: To characterize these effects in a large series of RSA cases that were 3D planned with pre-operative planning software.   Methods: A retrospective review of RSA cases planned by a single surgeon using a commercially available 3D CT software planning program between 2018 and 2020 was conducted to evaluate the relationship between the 3D virtual reaming depth (mm) required to execute the planned 3D glenoid inclination change along with RSA indication and patient factors. Cases planned for reconstruction using structural graft (defined as planned backside seating <75%), those using an augmented glenoid baseplate, and cases with planned glenoid inclination greater than native glenoid inclination were excluded. Pearson’s correlation coefficient was calculated to evaluate the relationship between the planned reaming depth and the above factors. Results: Sixty-three cases met the inclusion criteria in 29 males (46%) and 34 females (54%). The indications for planning of RSA included 22 cases of rotator cuff arthropathy (35%), 26 cases of massive rotator cuff tears or fracture with no osteoarthritis (41%), and 15 cases of cuff-intact osteoarthritis (24%). The median native 3D inclination was 9 degrees (IQR=6-13). Seventy percent of cases were planned to have a final implant inclination of 0 degrees. The median amount of inferior glenoid reamed was 8 mm (IQR=6-10). Corrective reaming depth was strongly, positively correlated with planned degrees of inclination correction, r (61) =0.67, p<0.001. No significant correlation was found between reaming depth and RSA indication or any patient factor such as age or sex.  Conclusions: Corrective reaming depth of the inferior glenoid in 3D planned RSA cases is highly correlated with correction of superior glenoid inclination. Each 1-degree correction in inclination requires approximately 0.9 mm of inferior reaming. An average reaming depth of 8 mm in the current series was necessary to achieve an average 9-degree inclination correction to neutral tilt. What this study adds: This study quantifies the relationship and direct correlation between the degree of superior glenoid inclination correction and the depth of inferior reaming required in reverse shoulder arthroplasty.How this study might affect research, practice or policy: These findings provide surgeons with practical guidance for preoperative planning that may help optimize implant positioning, reduce unnecessary bone removal, and guide future research on implant design and surgical decision-making.Study Design: Basic Science Study; Computer ModelingLevel of Evidence: Level IV Keywords: reverse shoulder arthroplasty; three-dimensional planning; CT scan; glenoid inclination; glenoid corrective reaming  https://doi.org/10.70885/hmsj.2025.09.001

References

  1. Boileau P, Melis B, Duperron D, Moineau G, Rumian AP, Han Y. Revision surgery of reverse shoulder arthroplasty. J Shoulder Elbow Surg. 2013 Oct;22(10):1359–70. DOI: 10.1016/j.jse.2013.02.004
  2. Groh GI, Groh GM. Complications rates, reoperation rates, and the learning curve in reverse shoulder arthroplasty. J Shoulder Elbow Surg. 2014 Mar;23(3):388–94. DOI: 10.1016/j.jse.2013.06.002
  3. Gupta A, Thussbas C, Koch M, Seebauer L. Management of glenoid bone defects with reverse shoulder arthroplasty—surgical technique and clinical outcomes. J Shoulder Elbow Surg. 2018 May;27(5):853–62. DOI: 10.1016/j.jse.2017.10.004
  4. 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 Jun;30(6):1273–81. DOI: 10.1016/j.jse.2020.09.023
  5. Tashjian RZ, Beck L, Stertz I, Chalmers PN. Preoperative three-dimensional computer planning for reverse total shoulder arthroplasty and bone grafting for severe glenoid deformity. Shoulder Elb. 2021 Oct;13(5):492-501. DOI: 10.1177/1758573220908903
  6. Mehta N, Nicholson GP. Management of Glenoid Bone Loss in Primary Reverse Total Shoulder Arthroplasty. Curr Rev Musculoskelet Med. 2023 May 25;16(8):358–70. DOI: 10.1007/s12178-023-09845-z
  7. Dilisio MF, Warner JJP, Walch G. Accuracy of the Subchondral Smile and Surface Referencing Techniques in Reverse Shoulder Arthroplasty. Orthopedics [Internet]. 2016 Jul [cited 2025 Jan 12];39(4). Available from: https://journals.healio.com/doi/10.3928/01477447-20160610-04
  8. Gutiérrez S, Walker M, Willis M, Pupello DR, Frankle MA. Effects of tilt and glenosphere eccentricity on baseplate/bone interface forces in a computational model, validated by a mechanical model, of reverse shoulder arthroplasty. J Shoulder Elbow Surg. 2011 Jul;20(5):732–9. DOI: 10.1016/j.jse.2010.10.035
  9. 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 Apr;30(4):787–94. DOI: 10.1016/j.jse.2020.06.032
  10. Maurer A, Fucentese SF, Pfirrmann CWA, Wirth SH, Djahangiri A, Jost B, et al. Assessment of glenoid inclination on routine clinical radiographs and computed tomography examinations of the shoulder. J Shoulder Elbow Surg. 2012 Aug;21(8):1096–103. DOI: 10.1016/j.jse.2011.07.010
  11. Youderian AR, Iannotti JP. Preoperative Planning Using Advanced 3-dimensional Virtual Imaging Software for Glenoid Component in Anatomic Total Shoulder Replacement. Tech Shoulder Elb Surg. 2012 Dec;13(4):145–50. DOI:10.1097/BTE.0b013e318256022c
  12. Iannotti JP, Weiner S, Rodriguez E, Subhas N, Patterson TE, Jun BJ, et al. Three-Dimensional Imaging and Templating Improve Glenoid Implant Positioning. J Bone Jt Surg. 2015 Apr 15;97(8):651–8. DOI: 10.2106/JBJS.N.00493
  13. Chalmers PN, Beck L, Granger E, Henninger H, Tashjian RZ. Superior glenoid inclination and rotator cuff tears. J Shoulder Elbow Surg. 2018 Aug;27(8):1444–50. DOI: 10.1016/j.jse.2018.02.043
  14. Laver L, Garrigues GE. Avoiding superior tilt in reverse shoulder arthroplasty: a review of the literature and technical recommendations. J Shoulder Elbow Surg. 2014 Oct;23(10):1582–90. DOI: 10.1016/j.jse.2014.06.029
  15. Shah SS, Sahota S, Denard PJ, Provencher MT, Parsons BO, Hartzler RU, et al. Variability in total shoulder arthroplasty planning software compared to a control CT-derived 3D printed scapula. Shoulder Elb. 2021 Jun;13(3):268–75. DOI: 10.1177/1758573219888821
  16. Tashjian RZ, Martin BI, Ricketts CA, Henninger HB, Granger EK, Chalmers PN. Superior Baseplate Inclination Is Associated With Instability After Reverse Total Shoulder Arthroplasty. Clin Orthop. 2018 Aug;476(8):1622–9. DOI: 10.1097/CORR.0000000000000340
  17. Boileau P, Gauci MO, Wagner ER, Clowez G, Chaoui J, Chelli M, et al. The reverse shoulder arthroplasty angle: a new measurement of glenoid inclination for reverse shoulder arthroplasty. J Shoulder Elbow Surg. 2019 Jul;28(7):1281–90. DOI: 10.1016/j.jse.2018.11.074
  18. Smith MJ, Loftis CM, Skelley NW. Eccentric Reaming for B2 Glenoids: History, Preoperative Planning, Surgical Technique, and Outcome. J Shoulder Elb Arthroplasty. 2019 Aug 22;3. DOI: 10.1177/2471549219870348
  19. Flieg NG, Gatti CJ, Doro LC, Langenderfer JE, Carpenter JE, Hughes RE. A stochastic analysis of glenoid inclination angle and superior migration of the humeral head. Clin Biomech Bristol Avon. 2008 Jun;23(5):554–61. DOI: 10.1016/j.clinbiomech.2008.01.001
  20. Gilot GJ. Addressing glenoid erosion in reverse total shoulder arthroplasty. Bull Hosp Jt Dis 2013. 2013;71 Suppl 2:S51-53. PMID: 24328581
  21. Kandemir U, Allaire RB, Jolly JT, Debski RE, McMahon PJ. The relationship between the orientation of the glenoid and tears of the rotator cuff. J Bone Joint Surg Br. 2006 Aug;88(8):1105–9. DOI: 10.1302/0301-620X.88B8.17732
  22. Konrad GG, Markmiller M, Jolly JT, Ruter AE, Sudkamp NP, McMahon PJ, et al. Decreasing glenoid inclination improves function in shoulders with simulated massive rotator cuff tears. Clin Biomech Bristol Avon. 2006 Nov;21(9):942–9. DOI: 10.1016/j.clinbiomech.2006.04.013
  23. Daggett M, Werner B, Collin P, Gauci MO, Chaoui J, Walch G. Correlation between glenoid inclination and critical shoulder angle: a radiographic and computed tomography study. J Shoulder Elbow Surg. 2015 Dec;24(12):1948–53. DOI: 10.1016/j.jse.2015.07.013
  24. Kirsch JM, Patel M, Singh A, Lazarus MD, Williams GR, Namdari S. Early clinical and radiographic outcomes of an augmented baseplate in reverse shoulder arthroplasty for glenohumeral arthritis with glenoid deformity. J Shoulder Elbow Surg. 2021 Jul;30(7S):S123–30. DOI: 10.1016/j.jse.2020.12.010
  25. Levin JM, Bokshan S, Roche CP, Zuckerman JD, Wright T, Flurin PH, et al. Reverse shoulder arthroplasty with and without baseplate wedge augmentation in the setting of glenoid deformity and rotator cuff deficiency—a multicenter investigation. J Shoulder Elbow Surg. 2022 Dec;31(12):2488–96. DOI: 10.1016/j.jse.2022.04.025
  26. Van Haver A, Heylen S, Vuylsteke K, Declercq G, Verborgt O. Reliability analysis of glenoid component inclination measurements on postoperative radiographs and computed tomography-based 3D models in total and reversed shoulder arthroplasty patients. J Shoulder Elbow Surg. 2016 Apr;25(4):632–40. DOI: 10.1016/j.jse.2015.09.003
  27. Colasanti CA, Lin CC, Ross KA, Luthringer T, Elwell JA, Roche CP, et al. Augmented baseplates yield optimum outcomes when compared with bone graft augmentation for managing glenoid deformity during reverse total shoulder arthroplasty: a retrospective comparative study. J Shoulder Elbow Surg. 2023 May;32(5):958–71. DOI: 10.1016/j.jse.2022.10.015
  28. 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 Dec;73 Suppl 1:S129-135. PMID: 26631209
  29. Liuzza L, Mai DH, Grey S, Wright TW, Flurin PH, Roche CP, et al. Reverse Total Shoulder Arthroplasty with a Superior Augmented Glenoid Component for Favard Type-E1, E2, and E3 Glenoids. J Bone Joint Surg Am. 2020 Nov 4;102(21):1865–73. DOI: 10.2106/JBJS.19.00946
  30. Michael RJ, Schoch BS, King JJ, Wright TW. Managing Glenoid Bone Deficiency-The Augment Experience in Anatomic and Reverse Shoulder Arthroplasty. Am J Orthop Belle Mead NJ. 2018 Mar;47(3). DOI: 10.12788/ajo.2018.0014
  31. Virk M, Yip M, Liuzza L, Abdelshahed M, Paoli A, Grey S, 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 May;29(5):e196–204. DOI: 10.1016/j.jse.2019.09.031
  32. Merolla G, Giorgini A, Bonfatti R, Micheloni GM, Negri A, Catani F, et al. BIO-RSA vs. metal-augmented baseplate in shoulder osteoarthritis with multiplanar glenoid deformity: a comparative study of radiographic findings and patient outcomes. J Shoulder Elbow Surg. 2023 Nov;32(11):2264–75. DOI: 10.1016/j.jse.2023.04.028
  33. Aleem AW, Orvets ND, Patterson BC, Chamberlain AM, Keener JD. Risk of Perforation Is High During Corrective Reaming of Retroverted Glenoids: A Computer Simulation Study. Clin Orthop. 2018 Aug;476(8):1612–9. DOI: 10.1007/s11999.0000000000000302
  34. Rojas J, Meshram P, Srikumaran U, McFarland EG. Clinical and radiographic results of eccentric glenoid reaming in reverse total shoulder arthroplasty. Semin Arthroplasty JSES. 2022 Jun;32(2):405–14. https://doi.org/10.1053/j.sart.2021.12.005

Full text PDF