
==== Front
JSES Int
JSES Int
JSES International
2666-6383
Elsevier

S2666-6383(24)00119-1
10.1016/j.jseint.2024.04.014
Shoulder
Shoulder Arthroplasty
Quantifying bone loss and lateralization with standardized baseplate versus augmented baseplates
Shah Anup MD, MBA Anup.shah@bannerhealth.com
ab∗
Werner Brian MD c
Gobezie Rueben MD d
Denard Patrick MD e
Harmsen Samuel MD f
Brolin Tyler MD g
Bercik Michael MD h
Thankur Siddhant i
Doody Scott i
Knopf David i
Metcalfe Nick i
Lederman Evan MD ab
a Department of Orthopedic Surgery, University of Arizona, College of Medicine – Phoenix, Phoenix, AZ, USA
b Department of Orthopedic Surgery, Banner Sports Medicine, Scottsdale, AZ, USA
c Department of Orthopedic Surgery, University of Virginia, Charlottsville, VA, USA
d Department of Orthopedic Surgery, Cleveland Shoulder Institute, Cleveland, OH, USA
e Department of Orthopedic Surgery, Oregon Shoulder Institute, Medford, OR, USA
f Department of Orthopedic Surgery, Banner Health, Phoenix, AZ, USA
g Department of Orthopedic Surgery, Campbell Clinic, Memphis, TN, USA
h Department of Orthopedic Surgery, Lancaster Orthopedic Group, Lancaster, PA, USA
i Department of Orthopedic Surgery, Arthex, Inc, Naples, FL, USA
∗ Corresponding author: Anup Shah, MD, MBA, Banner Sports Medicine, 7400 N Dobson Rd – 2nd Floor, Scottsdale, AZ 85256, USA. Anup.shah@bannerhealth.com
06 5 2024
9 2024
06 5 2024
8 5 10551062
© 2024 The Authors
2024
https://creativecommons.org/licenses/by-nc-nd/4.0/ This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).
Background

Reverse shoulder arthroplasty continues to be utilized for the treatment of cuff tear arthropathy, glenohumeral degenerative joint disease, and irreparable rotator cuff tears. With advancement in component designs, glenoid retroversion and inclination are now correctable with augmented baseplates. However, quantifying bone loss and lateralization compared to standard baseplates has not been studied. The purpose of the current study is to determine the volume of bone reamed and net lateralization with a standardized baseplate vs. augmented baseplate when glenoid inclination was corrected to neutral.

Methods

A series of 21 computed tomography scans of patients presenting for shoulder arthroplasty were chosen based on a range of increasing native positive inclination. Computed tomography scans were uploaded into segmentation software and processed. Four fellowship trained shoulder surgeons were then blinded from each other and virtually placed a neutral baseplate and an augmented baseplate for each specimen. Baseplate position was standardized. Additionally, baseplate backside seating of a minimum of 80% was also standardized and glenosphere (nonlateralized) size was selected to eliminate variation in baseplate contact and position. Glenoid inclination was corrected to a minimal of neutral in each specimen as well as glenoid retroversion corrected to <10°. Net lateralization from the center of the glenoid to the most lateral aspect of the baseplate was calculated in millimeters.

Results

The mean glenoid retroversion was 8.1° and superior inclination was 10.6° for all specimens. Across all specimens and surgeons, use of a 10-degree augment resulted in similar baseplate backside seating area (219.2 mm3 vs. 226.2 mm3, P > .05). There was substantially lower volume of bone reamed in the augmented baseplate patients (619 mm3 vs. 1102 mm3, P < .001). Larger standard deviation seen in the augmented baseplate columns are attributed to differences in surgeon preference for percent backside seating, which was standardized at a minimum of 80%. Use of a 10-degree full wedge augment resulted in 2.4 mm additional glenoid lateralization than a neutral baseplate on average across all included scapulae.

Conclusion

The current study demonstrates approximately 50% less bone removal and 2.4 mm of true lateralization with a 10-degree augmented baseplate when compared to standard baseplates.

Keywords

Glenoid bone loss
Augmented baseplate
Reverse shoulder arthroplasty
Glenoid inclination
Reverse shoulder angle
Baseplate position
==== Body
pmcAs reverse shoulder arthroplasty (RSA) continues to gain popularity in the treatment of rotator cuff tear arthropathy, glenohumeral joint degenerative joint disease, and irreparable rotator cuff tears, increased focus has been placed on maximizing the amount of glenoid bone stock remaining. Avoiding unnecessary reaming and its associated bone loss is paramount as nearly 40% of patients undergoing RSA already have some degree of glenoid bone loss.7,15 In an effort to minimize reaming and preserve glenoid bone, bony increased offset-reverse shoulder arthroplasty (BIO-RSA) and, more recently, metallic augmented baseplates have enabled surgeons to correct pathologic version or inclination while restoring the native glenohumeral joint line and adopting a more lateralized center of rotation.

BIO-RSA has been reported to have high rates of incorporation as shown by Boileau and Lorenzetti et al, though meticulous technique, patient characteristics, and fixation may affect osseous integration.5,17 In contrast to these studies, others have reported less favorable outcomes with significant resorption of structural bone grafts in up to 25% of cases.12,14 Metallic augments arose as an alternate method to achieving glenoid deformity correction and lateralization that negated concerns over bone graft resorption as well as the technically demanding nature of glenoid bone grafting.

Newer version of augmented baseplates enables up to four millimeters of lateralization and correction of inclination and version without medialization of the paleo glenoid in ten and fifteen-degree augments (Arthrex MGS Baseplate; Arthrex Inc., Naples, FL, USA). In addition, augmented baseplates allow surgeons to obtain the neutral or inferior inclination without compromising inferior glenoid bone. The purpose of the current study was to determine the volume of bone reamed and net lateralization with a standardized baseplate vs. augmented baseplate when glenoid inclination was corrected to neutral. We hypothesized that there would be no difference in volumetric bone loss or net lateralization when using an augmented baseplate as compared to a standard baseplate.

Materials and methods

A series of 21 pathological computed tomography scans of patients presenting for shoulder arthroplasty were chosen based on a range of increasing native positive inclination. Computed tomography scans were then uploaded into the OrthoVis (Arthrex Inc., Naples, FL, USA) segmentation software and processed generating a stereolithography mesh model of the chosen anatomy. Within the software, the implant was then virtually positioned with no alteration in version or inclination, and a central implant axis was loaded coincidental to the scapular line (projection line from glenoid center to the central point of the trigonum scapulae). The implant was then lateralized to minimal backside contact with glenoid surface (∼0% seating). Implant was placed at absolute bare-minimum touch off at 1% backside contact or ∼1-5 mmˆ2. This was done solely to guarantee that the implant is within a planable range but does not “guide” the surgeon in its placement. A central bore was then created along the implant central axis which was then used as an analytical reference (Fig. 1). This was repeated across all 21 specimens creating a centralized baseline implant placement.Figure 1 A central bore was then created along the implant central axis which was then used as an analytical reference.

These cases were uploaded to the Virtual Implant Positioning (VIP) (Arthrex Inc., Naples, FL, USA) portal for surgeon planning. The stereolithography was then exported from OrthoVis and processed in 3-matic (Materialise NV, Leuven, Belgium) to remove erroneous mesh features. Subsequently, the computer aided design (CAD) compatible file was imported into SolidWorks (Dassault Systèmes, Vélizy-Villacoublay, France), a CAD-software, where a SolidWorks environment (Figs. 2 and 3) was created to reproduce the implant positions selected by the surgeons for each unique anatomy and within each phase. The environment assemblies were designed to mimic the implant adjustment controls from the VIP portal.Figure 2 SolidWorks environment was created to reproduce the implant positions selected by the surgeons for (A) each unique anatomy and (B) within each phase.

Figure 3 SolidWorks environment was created to reproduce the implant positions selected by the surgeons for (A) each unique anatomy (B) and within each phase.

All relevant implants and augmented combinations were also imported into the SolidWorks environment in a CAD format. The implants utilized in the study were Arthrex implants (modular glenoid system baseplate and glenospheres). These implants were then positionally controlled by a series of 6 controllers: an anterior-posterior (AP) controller, a lateral-medial (LM) controller, superior-inferior (SI), version controller, inclination controller, and roll controller. The positional controllers were adjusted by 1 mm increments, and the angular controllers by 1° increments. The central axis acted as a 0 point (0, 0, 0; 0°, 0°, 0°) with controller offsets corresponding to the planned offset values (superior-inferior, AP, LM; Version, Roll, Inclination). For the planned example shown (Fig. 4), the corresponding positional controller values would be SI = 2.5 mm, AP = 1 mm, LM = 4.5 mm, and the corresponding angular values would be Version = -9°, Inclination = 0°, and Roll = 0° (2.5, 1, 4.5; -9°, 0°, 0°).Figure 4 Example of the corresponding positional controller (values would be SI = 2.5 mm, AP = 1 mm, LM = 4.5 mm, and the corresponding angular values would be Version = -9°, Inclination = 0°, and Roll = 0° (2.5, 1, 4.5; -9°, 0°, 0°). SI, superior-inferior; AP, anterior-posterior; LM, lateral-medial.

Once the surgeon planned implant position was replicated in the SolidWorks environment, a virtual cut was used to simulate procedural reaming. This produced a backside surface contact area (Fig. 5) and volumetric representation of reamed volume (Fig. 6). Using the measure and mass properties tool provided by SolidWorks (Fig. 7), the backside surface contact area and the reaming volume were calculated. The backside seating surface area measurements were then verified by comparison against the backside seating data provided within the VIP portal to ensure the implant position was properly reproduced. Additionally, lateralization was measured from the glenoid center to the front face of the implant for each sample (Fig. 8).Figure 5 (A) Backside surface contact area and (B) volumetric representation of reamed volume.

Figure 6 (A) Backside surface contact area and (B) volumetric representation of reamed volume.

Figure 7 Calculation of the backside surface contact area and the reaming volume by SolidWorks.

Figure 8 Calculation of lateralization (measured from the glenoid center to lateral edge of implant).

Four fellowship trained shoulder surgeons were blinded from each other and virtually placed a neutral baseplate and an augmented baseplate (either 10-degree or 20-degree augmented full-wedge baseplate if indicated subjectively by each surgeon) for each specimen. Baseplate position was standardized to be placed on the inferior glenoid to have the inferior aspect of the glenosphere be directly in line with the inferior margin of the glenoid (Fig. 9). Additionally, baseplate backside seating of a minimum of 80% was standardized and glenosphere (nonlateralized) size was selected to eliminate variation in baseplate contact and position. Glenoid inclination was corrected to a minimal of neutral in each specimen as well as glenoid retroversion corrected to <10°. Net lateralization from the center of the glenoid to the most lateral aspect of the baseplate was calculated in millimeters.Figure 9 Baseplate standardization based on glenosphere placement.

Results

Baseline data

Baseline measurements (version and inclination) for the twenty-one scapulae are noted in Table I. Mean glenoid retroversion was 8.1°, and superior inclination was 10.6°. The area of backside seating and volumetric bone loss is shown in Table II. Average backside seating area was found to be 219 mm2 (standard deviation [SD] 2.0), 226 mm2 (SD 9.3), and 241 mm2 (SD 10.5) for standard, 10-degree, and 20-degree augments, respectively. Additionally, volumetric bone loss decreased with increasing augments when inclination was corrected to 0 degrees. Standard baseplates required 1102 mm3 bone removed compared to 619.6 mm3 and 615.3 mm3 for 10-degree and 20-degree, respectively. Net lateralization increased by 2.4 mm from standard baseplate to a 10-degree augmented baseplate and another 2.4 mm with use of the 20-degree augmented baseplate.Table I Glenoid retroversion and superior inclination for each scapula as well as mean inclination and version.

Inclination_#	Version	Inclination	Inclination range	
1	−8.8	1.0	0-3	
2	−14.5	1.3	
3	−4.7	2.3	
4	−11.2	4.0	4-6	
5	−4.7	5.2	
6	−6.2	5.7	
7	−8.8	6.2	7-9	
8	−2.4	7.7	
9	−10.7	9.0	
10	−1.8	10.3	10-12	
11	−13.1	11.6	
12	−8.4	11.9	
13	−5.7	13.0	13-15	
14	−2.0	13.4	
15	−13.1	13.8	
16	−3.3	16.0	16-18	
17	−11.7	16.0	
18	−9.4	16.1	
19	−4.9	19.1	19-21	
20	−9.9	19.2	
21	−14.3	20.2	
Mean	−8.1	10.6		

Table II Backside seating of the glenoid baseplate as shown in area (mm2), volumetric bone loss through reaming as shown in volume (mm3), and glenoid lateralization as shown in lateralization (mm) for each surgeon as well as the mean and standard deviation for each of the baseplates planned.

	Standard baseplate (N = 21)	10° augment	20° augment	
Surgeon	Area (mm2)	Volume (mm3)	Lateralization (mm)	Area (mm2)	Volume (mm3)	Lateralization (mm)	Area (mm2)	Volume (mm3)	Lateralization (mm)	
 1	221.1	995.8	7.9	218.6	526.5	10.1	236.3	474.3	12.3	
 2	221.2	1350.7	7.5	228.6	714.0	10.3	241.6	486.1	13.1	
 3	216.5	859.7	7.7	217.3	560.7	9.5	229.4	795.2	11.5	
 4	217.8	1202.4	7.5	240.3	677.3	10.0	257.9	705.5	12.6	
Mean	219.2	1102.1	7.6	226.2	619.6	10.0	241.3	615.3	12.4	
SD	2.0	188.4	0.2	9.3	78.0	0.3	10.5	138.8	0.6	
SD, standard deviation.

Data interpretation

Across all specimens and surgeons, use of a 10-degree augment resulted in similar baseplate backside seating area (219.2 mm3 vs. 226.2 mm3, P > .05), but substantially lower volume of bone reamed in the augmented baseplate patients (619 mm3 vs. 1102 mm3, P < .001). Larger SD seen in the augmented baseplate columns are attributed to differences in surgeon preference for percent backside seating, which was standardized at a minimum of 80%. Use of a 10-degree full wedge augment resulted in 2.4 mm additional glenoid lateralization than a neutral baseplate on average across all included scapulae. When the surgeon indicated a 20-degree full wedge augment, it resulted in similar backside seating area and volume of bone reamed compared to 10-degree augments but resulted in an additional 2.4 mm of glenoid lateralization compared to 10-degree augments.

Discussion

We hypothesized that there would be no difference in volumetric bone loss or net lateralization when using an augmented baseplate as compared to a standard baseplate. The results of this study demonstrate a lower volume of glenoid bone removed (approximately 45%) with comparable backside seating with augmented glenoid baseplates compared to neutral baseplates in glenoids with an inclination angle >0. Additionally, the current study suggests augmented baseplates increased the net lateralization by 2.4 mm and 4.8 mm for 10-degree and 20-degree augments, respectively. Therefore, we disproved our hypothesis and showed that augmented baseplates decrease volumetric bone loss and add to net lateralization.

The advantages of correcting superior inclination, preserving bone, and providing/maintaining lateralization were seen in the current study with the use of metallic augments. Currently, pathologic glenoids have been addressed with eccentric reaming, alternate center line preference, BIO-RSA with or without bone graft, and/or metallic augmented baseplates. The use of augmented glenoid has the benefits of bone preservation (vs eccentric reaming), avoiding excessive glenoid component anteversion (alternate center line), and bone resorption (bone grafting).

The benefit of correcting superior inclination has been shown to increase implant stability18,20 as well as reduce shear forces seen at the baseplate/bone interface.16 The terms inclination and reverse shoulder angle merit some discussion given the consequences of superior glenoid baseplate tilt. The inclination angle (Beta angle) was initially described to depict the global inclination of the glenoid in anatomic shoulder arthroplasty. However, to avoid inadvertent superior tilting of the baseplate in RSA, Boileau advocated for the use of the RSA angle as opposed to the Beta angle when assessing for superior inclination of the glenoid.4 In addition, recent work by Amini also proposed the modified RSA angle based on varying, recommended positions of different baseplates.1

Multiple studies have commented on the benefits and outcomes of preserving glenoid bone stock with augmented baseplates.3,8,13,19 Bauer et al published their results in 37 patients showing augmented baseplates are effective at preserving bone stock and improving range of motion and patient reported outcomes at two years in patients without significant bone loss and correction to five degrees of inferior tilt. Additionally, Jones et al showed no complications and a lower scapular notching rate in the augmented baseplate cohort when compared to the bone graft cohort in their study. The current study not only corroborates the findings of Bauer but also quantifies the volume of bone preserved with augmented baseplates in pathologic glenoids. Specifically, 45% higher volume of bone is removed with standard baseplates when an inclination between a and b is identified.

The ability to maximize baseplate seating is also important as this allows surgeons to maximize initial implant stability. We chose to achieve (80%) backside baseplate seating as this is well above the threshold seen by Formaini et al, who demonstrated no difference in baseplate fixation when at least 50% of the baseplate was in contact with the native bone.6 Notably, however, the authors compared nonlateralized glenoid designs which may not be applicable to lateralized glenoid designs, especially as moving the center of rotation away from the glenoid increases shear force seen on the implant/bone interface.11 With augmented baseplates, satisfactory baseplate seating was achieved with the favorable characteristics of minimizing volumetric bone loss and allowed for glenoid component lateralization.

Lateralized constructs continue to gain popularity given potential benefits such as increased impingement-free range of motion, increased active external rotation, increased component stability, and decreased scapular notching.9,2,10,21,22 There are several methods to produce lateralization through implant characteristics and fixation and surgical technique. Each of these presents potential advantages and disadvantages. For instance, humeral lateralization may occur with thicker polyethylene liners; however, this may come at the cost of increased poly wear. Lateralization at the glenoid via lateralized baseplates and/or glenospheres provides another option but preparation of the glenoid prior to implantation medializes the position of the implant prior to implantation and, in effect, diminishes the true lateralization produced at the glenoid. As the optimal amount and methods of lateralization continues to be elucidated, the measurement of true lateralization, particularly at the glenoid, has become essential. With the addition of each 10° of metallic augmentation, reaming at the glenoid was minimized and 2.4 mm of effective glenoid lateralization was able to be achieved in this study based on the software parameters noted above. This consistent landmark allowed a standardized method to measure net lateralization with different glenoid components and varying reaming depths. Additionally, with increasing glenoid deformity, the addition of metallic augments avoids volumetric glenoid bone loss through reaming and subsequent medialization of the joint line. Ultimately, this will permit the surgeon to plan more accurately offset preoperatively.

The limitations of the current study are like those of any software study. Current limitations in most preoperative planning software programs permit measure inclination measurements only, and as such, this was utilized in the current study. Additionally, inclination and version are based on references marked by the technician/surgeon determined within the computer software. This can add variability to the inclination and version despite reliability and validity measurements. While this study attempted to standardize baseplate position through glenosphere placement, there may be some small variability in positioning. Lastly, the current study only evaluated inclination and not version. Future studies evaluating biplanar correction would permit optimal placement of a bone graft or metallic augment.

Conclusion

The current study demonstrates approximately 50% less bone removal and 2.4 mm of true lateralization with a 10-degree augmented baseplate when compared to standard baseplates.

Disclaimers:

Funding: 10.13039/100007307 Arthrex, Inc , funded this study.

Conflicts of interest: Dr. Shah is a consultant for Arthrex and receives royalties from Medacta. Dr. Werner is a consultant for Arthrex and receives research support from Biomet and Flexion Therapeutics. Dr. Lederman is a consultant for and receives royalties from Arthrex, Inc. Dr. Gobezie is a consultant for and receives royalties from Arthrex, Inc. Dr. Denard is a consultant for and receive royalties from Arthrex, Inc. Dr. Harmsen is a consultant for Arthrex, Inc. Dr. Brolin is a consultant for Arthrex, Inc. Dr. Bercik is a consultant for Arthrex, Inc. The other authors, their immediate families, and any research foundation with which they are affiliated have not received any financial payments or other benefits from any commercial entity related to the subject of this article.

Institutional review board approval was not required for this study.
==== Refs
References

1 Roache W. Patel M. Castaneda P. Hui C. Amini M. The modified reverse shoulder arthroplasty angle: the effect of both glenoid fossa size and implant size on the relevant inclination of the glenoid Seminars in Arthroplasty: JSES 34 2024 326 331
2 Arenas-Miquelez A. Murphy R.J. Rosa A. Caironi D. Zumstein M.A. Impact of humeral and glenoid component variations on range of motion in reverse geometry total shoulder arthroplasty: a standardized computer model study J Shoulder Elbow Surg 30 2021 763 771 10.1016/j.jse.2020.07.026 32763384
3 Bauer J.A. Slowinski J.J. Feng L. Sperling J.W. Duquin T.R. Optimizing glenoid bone preservation in reverse total shoulder arthroplasty using augmented baseplates JSES Rev Rep Tech 3 2023 77 82 10.1016/j.xrrt.2022.10.008 37588078
4 Boileau P. Gauci M.O. Wagner E.R. The reverse shoulder arthroplasty angle: a new measurement of glenoid inclination for reverse shoulder arthroplasty J Shoulder Elbow Surg 28 2019 1281 1290 10.1016/j.jse.2018.11.074 30935825
5 Boileau P. Morin-Salvo N. Gauci M.O. Angled BIO-RSA (bony-increased offset-reverse shoulder arthroplasty): a solution for the management of glenoid bone loss and erosion J Shoulder Elbow Surg 26 2017 2133 2142 10.1016/j.jse.2017.05.024 28735842
6 Formaini N.T. Everding N.G. Levy J.C. The effect of glenoid bone loss on reverse shoulder arthroplasty baseplate fixation J Shoulder Elbow Surg 24 2015 e312 e319 10.1016/j.jse.2015.05.045 26164482
7 Frankle M.A. Teramoto A. Luo Z.P. Levy J.C. Pupello D. Glenoid morphology in reverse shoulder arthroplasty: classification and surgical implications J Shoulder Elbow Surg 18 2009 874 885 10.1016/j.jse.2009.02.013 19482489
8 Gilot G.J. Addressing glenoid erosion in reverse total shoulder arthroplasty Bull Hosp Jt Dis (2013) 71 Suppl 2 2013 S51 S53 24328581
9 Gutiérrez S. Comiskey C.A. Luo Z.P. Pupello D.R. Frankle M.A. 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 90 2008 2606 2615 10.2106/JBJS.H.00012 19047705
10 Gutiérrez S. Keller T.S. Levy J.C. Lee W.E. Luo Z.P. Hierarchy of stability factors in reverse shoulder arthroplasty Clin Orthop Relat Res 466 2008 670 676 10.1007/s11999-007-0096-0 18264855
11 Henninger H.B. Barg A. Anderson A.E. Bachus K.N. Burks R.T. Tashjian R.Z. Effect of lateral offset center of rotation in reverse total shoulder arthroplasty: a biomechanical study J Shoulder Elbow Surg 21 2012 1128 1135 10.1016/j.jse.2011.07.034 22036546
12 Ho J.C. Thakar O. Chan W.W. Nicholson T. Williams G.R. Namdari S. Early radiographic failure of reverse total shoulder arthroplasty with structural bone graft for glenoid bone loss J Shoulder Elbow Surg 29 2020 550 560 10.1016/j.jse.2019.07.035 31610940
13 Jones R.B. Wright T.W. Roche C.P. Bone grafting the glenoid versus use of augmented glenoid baseplates with reverse shoulder arthroplasty Bull Hosp Jt Dis (2013) 73 Suppl 1 2015 S129 S135 26631209
14 Jones R.B. Wright T.W. Zuckerman J.D. Reverse total shoulder arthroplasty with structural bone grafting of large glenoid defects J Shoulder Elbow Surg 25 2016 1425 1432 10.1016/j.jse.2016.01.016 27039671
15 Klein S.M. Dunning P. Mulieri P. Pupello D. Downes K. Frankle M.A. Effects of acquired glenoid bone defects on surgical technique and clinical outcomes in reverse shoulder arthroplasty J Bone Joint Surg Am 92 2010 1144 1154 10.2106/JBJS.I.00778 20439660
16 Knighton T.W. Chalmers P.N. Sulkar H.J. Aliaj K. Tashjian R.Z. Henninger H.B. Reverse total shoulder glenoid component inclination affects glenohumeral kinetics during abduction: a cadaveric study J Shoulder Elbow Surg 31 2022 2647 2656 10.1016/j.jse.2022.06.016 35931329
17 Lorenzetti A. Streit J.J. Cabezas A.F. Bone graft augmentation for severe glenoid bone loss in primary reverse total shoulder arthroplasty: outcomes and evaluation of host bone contact by 2D-3D image registration JB JS Open Access 2 2017 e0015 10.2106/JBJS.OA.17.00015
18 Randelli P. Randelli F. Arrigoni P. Optimal glenoid component inclination in reverse shoulder arthroplasty. How to improve implant stability Musculoskelet Surg 98 Suppl 1 2014 15 18 10.1007/s12306-014-0324-1
19 Sperling J.W. Pearls and tips in shoulder arthroplasty Clin Orthop Surg 11 2019 258 10.4055/cios.2019.11.3.258 31475044
20 Tashjian R.Z. Martin B.I. Ricketts C.A. Henninger H.B. Granger E.K. Chalmers P.N. Superior baseplate inclination is associated with instability after reverse total shoulder arthroplasty Clin Orthop Relat Res 476 2018 1622 1629 10.1097/CORR.0000000000000340 29781910
21 Werner B.S. Chaoui J. Walch G. The influence of humeral neck shaft angle and glenoid lateralization on range of motion in reverse shoulder arthroplasty J Shoulder Elbow Surg 26 2017 1726 1731 10.1016/j.jse.2017.03.032 28528016
22 Werner B.C. Lederman E. Gobezie R. Denard P.J. Glenoid lateralization influences active internal rotation after reverse shoulder arthroplasty J Shoulder Elbow Surg 30 2021 2498 2505 10.1016/j.jse.2021.02.021 33753271
