Abstract
Aims
The objective of this study was to compare simulated range of motion (ROM) for reverse total shoulder arthroplasty (rTSA) with and without adjustment for scapulothoracic orientation in a global reference system. We hypothesized that values for simulated ROM in preoperative planning software with and without adjustment for scapulothoracic orientation would be significantly different.
Methods
A statistical shape model of the entire humerus and scapula was fitted into ten shoulder CT scans randomly selected from 162 patients who underwent rTSA. Six shoulder surgeons independently planned a rTSA in each model using prototype development software with the ability to adjust for scapulothoracic orientation, the starting position of the humerus, as well as kinematic planes in a global reference system simulating previously described posture types A, B, and C. ROM with and without posture adjustment was calculated and compared in all movement planes.
Results
All movement planes showed significant differences when comparing protocols with and without adjustment for posture. The largest mean difference was seen in external rotation, being 62° (SD 16°) without adjustment compared to 25° (SD 9°) with posture adjustment (p < 0.001), with the highest mean difference being 49° (SD 15°) in type C. Mean extension was 57° (SD 18°) without adjustment versus 24° (SD 11°) with adjustment (p < 0.001) and the highest mean difference of 47° (SD 18°) in type C. Mean abducted internal rotation was 69° (SD 11°) without adjustment versus 31° (SD 6°) with posture adjustment (p < 0.001), showing the highest mean difference of 51° (SD 11°) in type C.
Conclusion
The present study demonstrates that accounting for scapulothoracic orientation has a significant impact on simulated ROM for rTSA in all motion planes, specifically rendering vastly lower values for external rotation, extension, and high internal rotation. The substantial differences observed in this study warrant a critical re-evaluation of all previously published studies that examined component choice and placement for optimized ROM in rTSA using conventional preoperative planning software.
Cite this article: Bone Joint J 2024;106-B(11):1284–1292.
Take home message
Simulated range of motion in preoperative planning protocols is affected by adjustment for scapulothoracic orientation.
Considering individual body posture renders different results in all movement planes, especially external rotation, extension, and high internal rotation.
Introduction
In past decades, reverse total shoulder arthroplasty (rTSA) has emerged as a valuable option for various shoulder pathologies, restoring function and alleviating pain.1,2 Despite the positive outcomes associated with rTSA, some patients encounter certain challenges such as restricted range of motion (ROM), instability, component loosening, or scapular notching.3,4
With modern technologies such as 3D preoperative planning software, surgeons can explore different component combinations and placements for rTSA, in an attempt to maximize theoretical impingement-free ROM. However, recent literature suggests that there is a marked disparity between the calculated ROM and the actual clinical outcome.5-7 All current commercially available preoperative planning software for shoulder arthroplasty merely considers glenohumeral anatomy and does not account for scapular orientation with regard to the thorax. It has recently been shown that posture and scapulothoracic orientation, which vary between individuals, have an impact on theoretically achievable ROM in rTSA.8,9 For clinical application, variations in scapulothoracic orientation between patients were grouped into three different posture types (type A with upright posture and retracted scapulae; type B with average posture; and type C with advanced thoracic kyphosis and subsequent internal scapular rotation, anterior tilt, protraction, and drooping) (Figure 1).8
Fig. 1
Three posture types, based on previously established values for scapulothoracic orientation.8 Type A shows an upright posture with retracted scapulae, while type C presents with advanced thoracic kyphosis and subsequent increase in scapula internal rotation, anterior tilt, downward, rotation, protraction, and drooping. Type B constitutes an average patient. The statistical shoulder shape model of humerus and scapula fitted into different posture types is shown below each type.
The objective of this study was to compare simulated ROM for rTSA with prototype development software with and without adjustment for scapulothoracic orientation. We hypothesized that values for simulated ROM for rTSA with and without adjustment for scapulothoracic orientation would differ significantly.
Methods
Ethics
This study was based on CT data collected in a multicentre shoulder arthroplasty registry (Arthrex, USA) approved by its institutional review board (Salus IRB/AIRR-00608).
Shoulder statistical shape model
Based on a training set of 50 CT scans that included the entire humerus and scapula, a shoulder statistical shape model (SSM) was created. CT scans were collected from the Virtual Implant Positioning (VIP; Arthrex) database to represent the patient population. CT scans were obtained from 31 female and 19 male patients with a mean age of 71 years (34 to 93), including 33 right and 17 left shoulders. For the shoulder SSM, only right shoulders were considered and left shoulders were mirrored to simulate right shoulders. All patients with previous shoulder surgery, osteoarthritis, cuff arthropathy, or other bony pathology were excluded. All CT scans were manually segmented, and 3D surfaces of humerus and scapula were reconstructed using Mimics (Materialise, Belgium). To compute the shoulder SSM reference between all points, the training set surfaces were determined according to previously described methods for humeral and scapular correspondences computation.10,11 We then applied principal component analysis to compute the principal modes of variations – eigenvectors with eigenvalues – of the shoulder SSM. The calculated principal modes of variation allow for alterations of the shoulder SSM along the anatomical variations, so that a large number of shoulder models can be created.
Prototype development software
For the purpose of this study, preoperative planning software was created that allowed virtual implantation of a rTSA (Univers Revers; Arthrex). This prothesis is marked by a humeral semi-inlay design with a 135° neck-shaft angle and a modular glenoid system allowing for 4 mm baseplate lateralization and 4 mm glenosphere lateralization or eccentricity. The ROM is automatically calculated by rotating the humerus with the humeral implant around the centre of rotation (COR) in predefined reference systems, detecting collisions with an algorithm. Two sets of reference systems were defined in the software: scapular and global reference systems. The scapular reference system is defined as a best-fit plane between the trigonum scapulae, the glenoid centre, and the inferior angle, various superficial points (Y_s), a normal to this best-fit plane (X_s), and the cross product of those two planes (Z_s). The global reference system is defined as follows: X_g (sagittal plane), Y_g (coronal plane), and Z_g (axial plane) (Figure 2). For the conventional ROM calculation with the scapular reference system, the humerus is moved in relation to the scapula around the implant COR. Abduction and adduction movements are calculated around the X_s axis, flexion/extension movements are calculated around the Y_s axis, and internal and external rotations are calculated around the Z_s axis. To compute posture-adjusted ROM, the software rotates the scapula to the previously published mean values for the scapular internal rotation, upward/downward rotation, and anterior/posterior tilt of the scapula in respect of global reference axes for posture types A, B, and C (Table I; Figure 3).9 The starting position of the humerus is aligned according to the global reference system (Figure 2 and Figure 4). Abduction/adduction movements are calculated around the X_g axis, flexion/extension movements are calculated around the Y_g axis, and internal/external rotations are calculated around the Z_g axis.
Fig. 2
Illustration of scapular and global reference systems for abduction kinematic plane of the humerus applied in a type C patient in a coronal and transverse view. In all commercially available software, movements are referenced to the scapula, which is considered to be in neutral orientation. This means that an abduction motion is aligned with the scapular axis and not orthogonal to the coronal body axis, as would be the case utilizing a global reference system.
Table I.
Measurements for scapulothoracic orientation for individual posture types, based on previously published data.9
| Parameter | Type A | Type B | Type C |
|---|---|---|---|
| Mean scapular internal rotation, ° (SD) | 32 (6) | 42 (3) | 53 (5) |
| Mean scapular upward rotation, ° (SD) | -3 (6) | -12 (7) | -15 (13) |
| Mean scapular anterior tilt, ° (SD) | 23 (11) | 24 (8) | 33 (7) |
Fig. 3
Illustration of different scapulothoracic orientations in space in a type C patient. The scapula either did not adjust or adjusted according to types A, B, or C.
Fig. 4
Illustration of starting position of the humerus in a posture type C patient in three different types of commercially available planning software and a posture-adjusted software. In a standard software, the starting position is aligned with the scapula that is neutrally oriented in space. Therefore, considering the whole body and scapulothoracic orientation, the starting position of the humerus is incorrect. With a posture-adjusted software, a neutral starting position of the humerus can be achieved.
Preoperative planning
A SSM was fitted into ten shoulder CT scans randomly selected from 162 patients who underwent rTSA and six fellowship-trained shoulder surgeons (PM, PR, PJD, BCW, BJE, PS) independently planned a rTSA with their own preferences using the prototype development software (Arthrex). Possible choices for glenoid and humeral component selection and placement included all the commercially available choices for the implant system used. Simulated impingement-free ROM without and with posture adjustment for each type was obtained for the following movements: abduction, adduction, flexion, extension, external rotation (ER), external rotation in 30° abduction (hER), internal rotation (IR), and internal rotation in 30° abduction (hIR).
Statistical analysis
Statistical analysis including descriptive statistics were performed with SPSS Statistics software v. 29.0 (IBM, USA). The level of statistical significance was set to an α of 0.05, and all tests were two-sided. All outcome variables were analyzed using a Kolmogorov-Smirnov test and showed a normal distribution. For comparison of ROM outcomes between standard and adjusted software, a paired t-test was used.
Results
All movement planes showed significant differences in ROM when comparing results without adjustment and mean results for posture adjustment (Figure 5). Mean abduction was 77° (SD 4°) without adjustment compared to 81° (SD 5°) with posture adjustment (Mean pairwise differences (Δ) = 4°; p < 0.001). Adduction was 10° (SD 6°) without versus 19° (SD 14°) with posture adjustment (Δ = 9°; p < 0.001). While flexion was lower without adjustment (72° (SD 10°)) compared to 122° (SD 8°) with posture adjustment (Δ = 50°; p < 0.001), extension was higher without (57° (SD 18°)) compared to with (24° (SD 11°)) posture adjustment (Δ = -33°; p < 0.001). ER was 62° (SD 16°) without versus 25° (SD 9°) with posture adjustment (Δ = -36°; p < 0.001), while IR was 60° (SD 15°) without versus 99° (SD 19°) with posture adjustment (Δ = 39°, p < 0.001). While hER was 79° (SD 11°) without adjustment compared to 95° (SD 19°) with posture adjustment (Δ = 16°; p < 0.001), hIR was 69° (SD 11°) without versus 31° (SD 6°) with posture adjustment (Δ = -38°; p < 0.001).
Fig. 5
Comparison of the mean simulated mean range of motion (ROM) and SD in different planes simulated without posture adjustment protocol (black) to mean ROM with a posture-adjusted protocol (blue). *p < 0.001, paired t-test. ER, external rotation; hER, high external rotation; hIR, high internal rotation; IR, internal rotation.
Individual results comparing ROM without adjustment to each posture type (A, B, and C) are seen in Figure 6. All movement planes showed significant differences (p < 0.001), except for hER in type B (p = 0.610), abduction (p = 0.003) and adduction (p = 0.032) in type C. Mean pairwise differences are summarized in Table II. Figure 7 shows diffent contact areas between the humeral component and the scapula for conventional and posture adjusted planning software.
Fig. 6
Comparison of the mean range of motion and SD in different planes simulated without posture adjustment protocol to an adjusted protocol for all posture types. *p < 0.001, †p < 0.05, paired t-test; ER, external rotation; hER, high external rotation; hIR, high internal rotation; IR, internal rotation.
Table II.
Pairwise differences (Δ) in simulated mean range of motion between non-adjusted and adjusted preoperative shoulder arthroplasty planning software.
| Variable | Mean Δ, ° (SD; range) | ||
|---|---|---|---|
| Non-adjusted vs type A adjusted | Non-adjusted vs type B adjusted | Non-adjusted vs type C adjusted | |
| Abduction | 8 (3; 4 to 17) | 3 (3; 0 to 11) | 4 (3; 0 to 13) |
| Adduction | 11 (7; 2 to 38) | 15 (10; 0 to 49) | 13 (10; 0 to 51) |
| Flexion | 53 (11; 32 to 84) | 46 (11; 26 to 83) | 51 (11; 30 to 88) |
| Extension | 24 (18; 2 to 68) | 31 (19; 2 to 68) | 47 (18; 13 to 80) |
| External rotation | 27 (16; 0 to 60) | 33 (16; 4 to 64) | 49 (15; 23 to 80) |
| Internal rotation | 28 (15, 0 to 54) | 41 (15, 2 to 77) | 48 (14, 15 to 84) |
| External rotation in 30° abduction | 18 (11, 2 to 45) | 22 (17, 0 to 51) | 29 (19, 2 to 60) |
| Internal rotation in 30° abduction | 27 (11, 6 to 47) | 35 (11, 13 to 54) | 51 (11, 30 to 71) |
-
ER, external rotation; hER, high external rotation; hIR, high internal rotation; IR, internal rotation.
Fig. 7
Illustration of range of motion (ROM) simulation in a type C patient using a) a conventional preoperative planning protocol and b) a posture-adjusted protocol. Due to the altered scapulothoracic orientation, simulated mechanical impingement occurs in different areas of the scapula (red and yellow), explaining divergent ROM results between protocol with and without posture adjustment. ER, external rotation; hER, high external rotation; hIR, high internal rotation; IR, internal rotation.
Discussion
The present study demonstrates the importance of incorporating scapulothoracic orientation and global reference planes when simulating ROM for rTSA. We observed large differences in most planes of motion and particularly overestimated values for extension, external rotation, and internal rotation in 30° of abduction using a conventional simulation protocol compared to a posture-adjusted protocol. These results question the validity of currently commercially available planning solutions to simulate ROM in rTSA and their value in helping to guide the user in optimizing implant position for the best outcomes. These available systems do not currently consider the patient-specific orientation of the scapula, starting point of the humerus, and COR of the joint, and thus may render misleading results.
The value of preoperative planning in understanding and addressing glenoid deformities is widely recognized.12-14 Studies have demonstrated that accurate component placement can be achieved by following a preoperative plan.15 This facilitates the precise positioning of the central screw or post and increases bony containment.16 Jacquot et al17 showed that using preoperative planning enhances the accuracy of freehand positioning, and patient-specific guides may even improve the position of the central entry point. Optimized glenoid component position may improve postoperative movement and decrease risk of complication, such as scapular notching.16 Furthermore, by using 3D planning techniques, surgeons can estimate the appropriate size of the glenoid baseplate and determine approximate screw lengths. Additionally, they can make reasonably accurate predictions regarding the required shaft sizes for the humeral component.15,18 With various component options available, surgeons can even simulate lateralization or distalization to achieve the desired configuration. One promising feature of commercially available planning software has been simulated ROM. These systems allow for the rotation of the humeral component around the glenosphere in multiple planes, enabling surgeons to assess potential mechanical impingement and provide a prediction of ROM that can be expected postoperatively. However, CT scans of the affected shoulder only capture the glenohumeral joint and disregard the natural relationship between the scapula, the humerus, and the thorax. As shown in Figure 3, in standard software, the scapula is used as a reference that defines the starting position of the humerus and the movement planes based on the scapular axis, rather than the individual body axes. As scapular rotation increases, as seen in type C patients, the disparity between the scapular and body axes (global reference) becomes more pronounced. The adjusted software used in this study not only accounts for changes in scapulothoracic orientation (types A, B, and C) but is uniquely calibrated to a global reference for humeral starting position and kinematic planes.
The substantial simulated ROM differences observed between posture-adjusted and non-adjusted planning software can be explained by the fact that the repositioning of the humerus and scapula in the global reference system leads to different contact scenarios in the various kinematic planes (Figure 7). The study findings revealed a significant difference in measured flexion when posture adjustment was implemented compared to when it was not, across all scapulothoracic orientation types. During flexion, in a standard simulation with the scapula in a straight position, the humeral component encounters interference with the coracoid process below 90°. Conversely, when considering scapular internal rotation within the same movement, the coracoid process is relatively medialized, allowing the humeral component to extend until it reaches the anterior acromion, enabling increased movement. In the analysis of rotational movement, the non-adjusted software demonstrated a balanced ROM for internal and external rotation and internal and external rotation in 30° of abduction. However, with incorporated posture adjustments, imbalances in rotational movement were observed. These findings align with previous studies that used simulations accounting for the humeral starting position in relation to the body axes.8,9 Specifically, it was observed that in 0° abduction, internal rotation was favoured when there was advanced scapular internal rotation (type C), while external rotation was diminished. This phenomenon has been previously described.9 Interestingly, in the case of 30° abduction, our simulation yielded opposing results compared to adducted rotation. Upon closer examination of the model (Figure 7), it can be observed that in type C patients, the changed scapulothoracic orientation resulted in early impingement with the coracoid process. However, there is more space available for rotation towards the posterosuperior part of the glenoid before encountering notching, which can explain a better abducted external rotation. These observations align with clinical observations where external rotation in adduction after rTSA may lead to early posteroinferior notching, while external rotation in 30° abduction has a larger range before notching occurs. Similarly, it might explain the often limited internal rotation after rTSA, such as reaching behind one’s back, which requires a combination of internal rotation and abduction resulting in an impingement with the coracoid. Baumgarten5 conducted a study to examine the disparities between ROM calculated using preoperative software and the actual active ROM observed at the one-year follow-up. Interestingly, they observed a similar pattern in external rotation compared to the results of our study. Their software tended to overestimate external rotation by an absolute difference of 28°, but underestimated it in abducted external rotation, with an absolute difference of 32°. Moreover, their software substantially overestimated abducted internal rotation, with an absolute difference of 62°. The biggest difference was found in abduction. However, it is crucial to note that their clinical measurements included scapulothoracic movement, while their simulation is based on glenohumeral motion only, which is also true for our study. Moreover, variances in humeral retrotorsion may impact both internal and external rotation, with each surgeon selecting their preferred rotation during planning. Increased retrotorsion is associated with greater external rotation, while decreased retrotorsion is associated with favoured internal rotation.19 However, the substantial differences in simulated ROM observed in this study justify re-evaluation of all previously published studies that examined component choice and placement for optimized ROM in rTSA using conventional preoperative planning software.
Despite the arguable improvement in simulating ROM after rTSA when scapulothoracic orientation is adjusted, certain limitations remain, including the lack of simulation of scapula kinematics and soft-tissue impingement. It is important to acknowledge that the simulation solely accounts for glenohumeral movement and does not consider scapulothoracic motion. Consequently, cautious interpretation is advised, particularly when assessing values of abduction and flexion in clinical practice. Furthermore, component choice for the surgeons and placement were not further analyzed in this study. Humeral component torsion in particular could have an impact on rotational movement. While this does not allow for interpretation of individual implantation styles on ROM outcome in different posture types, the effect of scapulothoracic orientation seems to be present across a variety of different configurations, as the planning was performed by six independent shoulder surgeons according to their individual preferences. Additionally, the simulation employed shape models that were chosen at random, which underlines the generalizability of the obtained results. Furthermore, the values used for scapulothoracic orientation of each posture type were based on previously published data.9 The obtained values were derived from whole-body CT scans in the supine position, which could affect scapulothoracic orientation. In a study comparing scapulothoracic orientation in supine and standing position, Matsumura et al20 observed less upward rotation, anterior tilting, and internal rotation of the scapula in the standing position. Analyzing standing patients could therefore offer more realistic values for scapulothoracic orientation, potentially enhancing diagnostic accuracy in preoperative planning.
The present study demonstrates that taking scapulothoracic orientation and global reference planes into account has considerable impact on simulated ROM for rTSA, specifically rendering much lower values for extension, external rotation, and internal rotation in 30° of abduction. The substantial differences in posture-adjusted and non-adjusted simulated ROM observed in this study question the validity of all currently commercially available solutions to simulate ROM in rTSA, and their value in guiding the surgeon to optimize implant position for the best outcome.
References
1. Best MJ , Aziz KT , Wilckens JH , McFarland EG , Srikumaran U . Increasing incidence of primary reverse and anatomic total shoulder arthroplasty in the United States . J Shoulder Elbow Surg . 2021 ; 30 ( 5 ): 1159 – 1166 . Crossref PubMed Google Scholar
2. Boileau P , Watkinson DJ , Hatzidakis AM , Balg F . Grammont reverse prosthesis: design, rationale, and biomechanics . J Shoulder Elbow Surg . 2005 ; 14 ( 1 Suppl S ): 147S – 161S . Crossref PubMed Google Scholar
3. Bohsali KI , Bois AJ , Wirth MA . Complications of shoulder arthroplasty . J Bone Joint Surg Am . 2017 ; 99-A ( 3 ): 256 – 269 . Crossref PubMed Google Scholar
4. Kriechling P , Zaleski M , Loucas R , Loucas M , Fleischmann M , Wieser K . Complications and further surgery after reverse total shoulder arthroplasty : report of 854 primary cases . Bone Joint J . 2022 ; 104-B ( 3 ): 401 – 407 . Crossref PubMed Google Scholar
5. Baumgarten KM . Accuracy of Blueprint software in predicting range of motion 1 year after reverse total shoulder arthroplasty . J Shoulder Elbow Surg . 2023 ; 32 ( 5 ): 1088 – 1094 . Crossref PubMed Google Scholar
6. Berhouet J , Samargandi R , Favard L , Turbillon C , Jacquot A , Gauci MO . The real post-operative range of motion differs from the virtual pre-operative planned range of motion in reverse shoulder arthroplasty . J Pers Med . 2023 ; 13 ( 5 ): 765 . Crossref PubMed Google Scholar
7. Sheth BK , Lima DJL , Drummond M , Grauer J , Rudraraju RT , Sabesan VJ . Assessment of 3D automated software to predict postoperative impingement free range of motion after reverse shoulder arthroplasty . Seminars in Arthroplasty: JSES . 2021 ; 31 ( 4 ): 783 – 790 . Crossref Google Scholar
8. Moroder P , Akgün D , Plachel F , Baur ADJ , Siegert P . The influence of posture and scapulothoracic orientation on the choice of humeral component retrotorsion in reverse total shoulder arthroplasty . J Shoulder Elbow Surg . 2020 ; 29 ( 10 ): 1992 – 2001 . Crossref PubMed Google Scholar
9. Moroder P , Urvoy M , Raiss P , et al. Patient posture affects simulated ROM in reverse total shoulder arthroplasty: a modeling study using preoperative planning software . Clin Orthop Relat Res . 2022 ; 480 ( 3 ): 619 – 631 . Crossref PubMed Google Scholar
10. Poltaretskyi S , Chaoui J , Mayya M , et al. Prediction of the pre-morbid 3D anatomy of the proximal humerus based on statistical shape modelling . Bone Joint J . 2017 ; 99-B ( 7 ): 927 – 933 . Crossref PubMed Google Scholar
11. Mayya M , Poltaretskyi S , Hamitouche C , Chaoui J . Mesh correspondence improvement using Regional Affine Registration: application to statistical shape model of the scapula . IRBM . 2015 ; 36 ( 4 ): 220 – 232 . Crossref Google Scholar
12. Larose G , Greene AT , Jung A , et al. High intraoperative accuracy and low complication rate of computer-assisted navigation of the glenoid in total shoulder arthroplasty . J Shoulder Elbow Surg . 2023 ; 32 ( 6S ): S39 – S45 . Crossref PubMed Google Scholar
13. Iannotti J , Baker J , Rodriguez E , et al. Three-dimensional preoperative planning software and a novel information transfer technology improve glenoid component positioning . J Bone Joint Surg Am . 2014 ; 96-A ( 9 ): e71 . Crossref PubMed Google Scholar
14. Nguyen D , Ferreira LM , Brownhill JR , et al. Improved accuracy of computer assisted glenoid implantation in total shoulder arthroplasty: an in-vitro randomized controlled trial . J Shoulder Elbow Surg . 2009 ; 18 ( 6 ): 907 – 914 . Crossref PubMed Google Scholar
15. Lilley BM , Lachance A , Peebles AM , et al. What is the deviation in 3D preoperative planning software? A systematic review of concordance between plan and actual implant in reverse total shoulder arthroplasty . J Shoulder Elbow Surg . 2022 ; 31 ( 5 ): 1073 – 1082 . Crossref PubMed Google Scholar
16. Berhouet J , Gulotta LV , Dines DM , et al. Preoperative planning for accurate glenoid component positioning in reverse shoulder arthroplasty . Orthop Traumatol Surg Res . 2017 ; 103 ( 3 ): 407 – 413 . Crossref PubMed Google Scholar
17. Jacquot A , Gauci MO , Chaoui J , et al. Proper benefit of a three dimensional pre-operative planning software for glenoid component positioning in total shoulder arthroplasty . Int Orthop . 2018 ; 42 ( 12 ): 2897 – 2906 . Crossref PubMed Google Scholar
18. Wittmann T , Befrui N , Rieger T , Raiss P . Stem size prediction in shoulder arthroplasty with preoperative 3D planning . Arch Orthop Trauma Surg . 2023 ; 143 ( 7 ): 3735 – 3741 . Crossref PubMed Google Scholar
19. Stephenson DR , Oh JH , McGarry MH , Rick Hatch GF , Lee TQ . Effect of humeral component version on impingement in reverse total shoulder arthroplasty . J Shoulder Elbow Surg . 2011 ; 20 ( 4 ): 652 – 658 . Crossref PubMed Google Scholar
20. Matsumura N , Yamada Y , Oki S , et al. Three-dimensional alignment changes of the shoulder girdle between the supine and standing positions . J Orthop Surg Res . 2020 ; 15 ( 1 ): 411 . Crossref PubMed Google Scholar
Author contributions
P. Moroder: Conceptualization, Data curation, Formal analysis, Investigation, Methodology, Writing – original draft
S. Poltaretskyi: Conceptualization, Data curation, Formal analysis, Investigation, Methodology, Resources, Software, Visualization, Writing – original draft
P. Raiss: Conceptualization, Formal analysis, Investigation, Writing – review & editing
P. J. Denard: Investigation, Methodology, Writing – review & editing
B. C. Werner: Investigation, Methodology, Writing – review & editing
B. J Erickson: Investigation, Methodology, Writing – review & editing
J. W. Griffin: Investigation, Methodology, Writing – review & editing
N. Metcalfe: Conceptualization, Investigation, Project administration, Software, Writing – review & editing
P. Siegert: Conceptualization, Data curation, Formal analysis, Investigation, Methodology, Visualization, Writing – original draft
Funding statement
The authors disclose receipt of the following financial or material support for the research, authorship, and/or publication of this article: S. Poltaretskyi is an employee of Arthrex, and P. Raiss is a paid consultant for Arthrex. P. Siegert reports software support from Arthrex for this study. B. C. Werner reports funding from Arthrex for this study. P. Moroder reports software support and article processing charges funding from Arthrex for this study, as well as consulting fees from and a patent submission with Arthrex, which are related to this study.
ICMJE COI statement
S. Poltaretskyi is an employee of Arthrex. P. Raiss is a paid consultant for Arthrex, and also receives speaker payments or honoraria and support for attending meetings and/or travel from Arthrex, and stock or stock options from Zurimed, all of which are unrelated to this study. P. Siegert reports software support from Arthrex for this study. B. C. Werner reports funding from Arthrex for this study, as well as consulting fees from Arthrex and Lifenet, and speaker payments or honoraria from Arthrex which are unrelated to this study. P. Moroder reports software support and article processing charges funding from Arthrex for this study, as well as consulting fees from and a patent submission with Arthrex, which are related to this study. P. Denard reports grant funding from Arthrex for this study, as well as royalties or licenses, consulting fees, and speaker payments or honoraria from Arthrex which are unrelated to this study. P. Denard also reports speaker payments or honoraria from Pacira and stock or stock options from PT Genie, unrelated to this study. B. J. Erickson reports consulting fees from Arthrex, unrelated to this study. J. Griffin reports royalties or licenses, consulting fees, speaker payments or honoraria, support for attending meetings and/or travel, and patents from Arthrex, all of which are unrelated to this study.
Data sharing
The datasets generated and analyzed in the current study are not publicly available due to data protection regulations. Access to data is limited to the researchers who have obtained permission for data processing. Further inquiries can be made to the corresponding author.
Open access funding
Arthrex funded the open access fee for this article.
Open access statement
This is an open-access article distributed under the terms of the Creative Commons Attribution Non-Commercial No Derivatives (CC BY-NC-ND 4.0) licence, which permits the copying and redistribution of the work only, and provided the original author and source are credited. See https://creativecommons.org/licenses/by-nc-nd/4.0/
This article was primary edited by G. Scott.
