Outcomes after revision of anatomic total shoulder arthroplasty to reverse shoulder arthroplasty and comparison between cemented or metal-backed glenoid in platform systems.

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Frantzeska Zampeli, Efi Kazum, Alejandro Gomez, Philippe Valenti This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-4296824/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract Background The objective of this study is to report the outcomes after revision of anatomical total shoulder arthroplasty (ATSA) to reverse shoulder arthroplasty (RSA) and to compare between groups depending on the primary ATSA glenoid implant type, cemented polyethylene (PE) versus a convertible metal-backed (MB). The hypothesis was that the outcomes would differ between patients treated with ATSA with PE and MB implants in favor of the platform system. Methods Group A included ten cases of convertible MB glenoid that were revised due to instability (six cases), posterosuperior rotator cuff tear (RCT) (two cases), subscapularis rupture (one case) and polyethylene dissociation (one case); Group B included ten cases of cemented PE that were revised due to glenoid loosening (six cases), RCT (two cases), dislocation (one case), and painful stiffness (one case). Active motion, Constant score, subjective shoulder value, Simple Shoulder Test and pain (VAS) were evaluated at minimum follow-up of two years. Student’s t test and Mann-Whitney tests were used for statistical analysis. Level of significance α=0.05. Results For the entire study cohort, postoperative results were improved compared to the preoperative state (p<0.05) at mean follow-up 60 months (24-188). Group A demonstrated improved postoperative pain levels compared to Group B (VAS 0.1 vs 1.9; p=0.004). No other differences were detected between the two groups (p>0.05). One complication occurred in Group B where one patient was re-operated for RSA instability with a good final functional outcome. Conclusions ATSA to RSA conversion resulted in improved functional outcomes. Post RSA motion and functional outcomes did not differ between the two groups with exception of reduced pain levels for patients treated with a convertible MB ATSA system. Level of evidence : III; retrospective comparative study; treatment study Anatomic total shoulder arthroplasty reverse shoulder arthroplasty revision platform shoulder system convertible system metal-backed glenoid implant Figures Figure 1 Figure 2 Figure 3 Figure 4 Background Failed anatomic total shoulder arthroplasty (ATSA) is an intriguing challenge for the orthopedic surgeon. The main causes that lead to ATSA failure and necessitate a revision surgery consist of glenoid loosening, prosthesis instability, rotator cuff tear, periprosthetic fracture, infection, implant failure and deltoid muscle dysfunction [ 1 – 3 ]. In addition, loss of humeral and glenoid bone stock, soft tissue compromise, and complications related to the failed prosthesis, render the restoration of a stable and functional joint highly difficult [ 4 – 7 ]. Glenoid loosening forms the weakest link in ATSA long-term survival and is often the reason for implant’s failure. Reverse shoulder arthroplasty (RSA) has been considered as the treatment of choice for failed ATSA cases, especially when associated with loss of glenoid bone stock or with an irreparable rotator cuff lesion [ 4 ]. However, ATSA’s cemented polyethylene (PE) implant removal may aggravate the glenoid bone defect and render implantation of the metal back of an RSA difficult [ 8 ]. According to reports, the use of a convertible total shoulder arthroplasty system with a convertible glenoid implant, technically facilitates ATSA to RSA conversion [ 5 , 8 – 14 ]. Such convertible platform systems allow for reductions in revisions’ duration time and associated complications by avoiding humeral stem and/or glenoid metal-backed (MB) component replacement [ 9 , 10 , 15 , 16 ]. The purpose of this study was to report the outcomes of ATSA to RSA revision surgeries and to compare patients’ clinical outcomes depending on the primary ATSA glenoid implant type, cemented PE versus a convertible MB. The primary hypothesis was that post RSA patients will demonstrate improved range of motion (ROM) and functional outcomes. Secondary hypothesis was that the clinical outcomes would differ between patients treated with ATSA with PE and MB implants in favor of the platform system. Methods Patients’ selection Between 2008 and 2018, 208 ATSAs were performed at a single institution. Among these, 20 patients underwent revision of failed ATSA with RSA. Primary and revision procedures were performed by the senior author (PV) and were available for follow up. The patients’ characteristics are described in table 1. (Table 1) Patients’ inclusion criteria consisted of 1) ATSA to RSA revision surgeries using a completely convertible RSA implant and 2) minimal clinical follow-up of 2 years. Exclusion criteria consisted of 1) revision of full PE of ATSA to a metal-backed ATSA (one case), 2) revision of full PE cemented ATSA to an hemiarthoplasty (one case), 3) deltoid palsy, 4) prosthetic infection, 5) revision with additional soft tissue procedure (3 cases). This study was classified as observational (non-interventional) by our local ethics committee. Statutory and ethical obligations of observational (non-interventional) studies in our country: According to the past Huriet law on biomedical research, and to the current regulation that went into effect in August 2006 (law n°2004-806), such studies do not require prior submission or approval to/from an IRB, and they do not require written consent. This observational research on data fulfils current local regulatory and ethical obligations. The study cohort was divided into two groups based on the glenoid implant type that was used at the primary ATSA procedure. Group A (10 cases) consisted of failed ATSAs that were primarily treated with MB glenoid convertible implant (FIGURE 1) and group B (10 cases) represented failed ΑTSA treated primarily with PE cemented glenoid (PE CG) implants (FIGURE 2). Data regarding the etiologies for primary ΑTSA surgeries and revision RSA surgeries are summarized in Table 1 (Table 1). For the primary ATSAs a convertible shoulder prosthesis (Arrow; FH Orthopedics, Mulhouse, France) that facilitates ATSA to RSA revision surgeries was used for most of the cases (FIGURE 1). The system offers a universal humeral stem and either a MB glenoid convertible or a cemented full PE glenoid implant. The MB component was preferred by the senior author if there are cysts in the glenoid, if there was a B1 or B2 glenoid and in case of rheumatoid arthritis. Conversion to a reverse prosthesis allows the surgeon to replace the humeral head metallic tray (ATSA) with a polyethylene insert (RSA) without removing the humeral stem. In case the glenoid implant is a MB device (all cases in group A), polyethylene shell removal exposes a well-fixed glenoid baseplate, which supports a glenosphere insertion. In 2 cases of group B, the PE cemented glenoid implant was part of ATSA with no convertible platform humeral stem implant (DePuy Synthes, J&J MedTech, MA, USA). Surgical technique and intraoperative findings All revisions were performed under general anesthesia and interscalene block for a better postoperative pain relief with the patient in a semi beach chair position and the arm in lying position on a support to relax the deltoid. A Reverse Arrow system (FH orthopedics, Mulhouse, France) was implanted in all cases. The previous deltopectoral approach was used, which could also allow for distal extension of the exposure in case of stem replacement. Adhesions at the deep part of the deltoid and the conjoint tendon were carefully released. Previous biceps tenodesis to the aponeurosis of pectoralis major was verified. In case of thin, fibrotic or considered as non-functional rotator cuff tear, or tear of the subscapularis or supraspinatus muscle, or both, causing instability, a conversion from an anatomic to an RSA was performed. When the subscapularis tendon could be retained, it was peeled off from the medial border of the bicipital groove to obtain sufficient length for a tension-free reinsertion. The RSA that was used (Arrow; FH Orthopedics, Mulhouse, France) allows lateralization in both components (glenosphere and humerus) and the subscapularis tendon was frequently medialized during transosseous reinsertion in order to maintain 30º of external rotation. Before implantation of the new prosthesis five tissue biopsies were collected systematically to search germs even in the absence of local or general infectious signs. The Arrow convertible system is a dual platform system, with a convertibility on both sides (humeral stem and the glenoid MB baseplate). Therefore, the system allows shifting from ATSA to RSA without any humeral stem and/or glenoid MB revision making surgery less demanding, less invasive and less time consuming (FIGURE 1). Nevertheless, the humeral stem had to be revised in cases of loosening or malposition (excessive retroversion/anteversion and/or too proud stem) (FIGURES 2,3). There were 10 cases with MB glenoid component (group A) and 10 cemented PE glenoid components (group B). In group A, the baseplate with a convex back covered with hydroxyapatite, a central keel and an anterior winglet is fixed with two cortical divergent screws. A 4mm thickness polyethylene is impacted into the baseplate. In group B the polyethylene component was pegged (four pegs). During conversion, the anatomic head of the humeral implant was disconnected from the stem and removed. In case of a MB glenoid component, the PE glenoid onlay was removed from the baseplate. No baseplate was loosened, and no baseplate has been removed in this group A (FIGURE 1). In the case of a cemented PE glenoid component, its replacement with a MB glenoid component was performed (FIGURES 2,3). After removing the PE glenoid component and cement, bone defects were reconstructed with cancellous graft (iliac crest bone autograft in one case, synthetic bone graft in one case, and humeral autograft from the humeral re-cut in one case). A metallic long-peg baseplate was used in 6 cases with 10 mm into the native bone. Inferior tilt and perforation of the anterior fossa of the scapula improved the press fit of the base plate. The shape and the lateralization of the metal back glenoid component (thickness 8.5 mm) allowed to decrease the necessity, or the amount of bone graft needed. The metallic long peg (FH orthopedics, Mulhouse, France) improves the primary stability of the glenoid component in glenoid deficiency (FIGURE 4). A glenosphere was impacted on the baseplate. Humeral stems were removed in 7 cases: 5 cases in group A (1 for humeral loosening and 4 to be placed in lower position because the stem was too proud and rendered the RSA irreducible) and 2 cases in group B (the stem was not convertible, DePuy Synthes, J&J MedTech, MA, USA). In all cases except from 1, removal of the stem was possible without osteotomy and, hence, was replaced with a new cemented stem in the correct high. For 1 case (group B) cortical osteotomy of the metaphyseal part was performed to change the humeral stem. A new cemented humeral stem was placed lower to facilitate the reduction of the prosthesis and wire cerclage was used for the fixation of the humerus (FIGURE 3). The metaphyseal part was re-cut and cancellous and chips bone graft allowed to obtain a press fit metaphyseal stem and cement into the diaphysis. A standard polyethylene humeral insert was implanted on the humeral stem in all cases. Postoperative rehabilitation All the patients were immobilized with a brace in neutral rotation maintained for four weeks. Passive ROM in forward elevation and external rotation begun immediately after the operation until pain limits. Active ROM and hydrotherapy were initiated at 6 weeks post-operatively and muscular strengthening of the external rotators and the depressor muscles represented the last step of rehabilitation that was initiated 3 months post-operatively. Patient assessment Pre- and post-operative clinical evaluation was performed by the senior author and included evaluation of functional scores: absolute Constant–Murley score (CMS), subjective shoulder value (SSV), Simple Shoulder Test (SST) and active ROM assessment including forward elevation (FE) at scapular level, external rotation with the arm at the side (ER1), external rotation in 90º of abduction (ER2) and internal rotation (IR). Subjective pain evaluation was recorded with the visual analogue scale (VAS) pain score from one to ten. Strength was measured with the arm in abduction of 90° in the plane of the scapula, with a resistance during five seconds against a hand-held dynamometer fixed at the level of the wrist. In addition, at the last follow up visit patients were asked to evaluate their degree of satisfaction from the final outcome using the following scale: very satisfied, satisfied, or fair. True antero-posterior (neutral, external and internal rotation) and scapular lateral radiographs were routinely performed pre- and post-operatively at the latest follow-up examination. Pre-operative computed tomography (CT) scans were performed to analyze bone deformity, glenoid bone stock, muscle trophicity and degree of fatty infiltration (according to Goutallier classification) [17]. We looked for evidence of glenoid component loosening (radiolucent lines around the PE cemented or the base plate, medialization of the PE component, hardware breakage and migration of base plate or PE) or scapular notching (graded according to the Sirveaux-Nerot classification) [18]. Intra- and post-operative complications were recorded. Statistical analysis The analysis was performed with the statistical battery provided by STATA® (version 11.0 for Mac OS; StataCorp, Texas, USA.). The Shapiro-Wilk test was used to assess the normal distribution of the results, according to the different groups. The Student’s t test or Mann–Whitney test were used to compare the preoperative and postoperative results for all values in the distinct groups, and between groups. Statistical significance was determined at a p-value < 0.05. Results Demographics and patients’ characteristics per group During the study period, 208 ATSAs were performed at our institution, 50 with MB glenoid component and 158 with PE cemented glenoid implant. Twenty patients (12 females) met the inclusion criteria and were evaluated with mean follow-up 60 months (24-188). The patients’ information for the whole study cohort and for groups A (MB, n=10) and B (PE CG, n=10) are demonstrated in table 1. No significant differences were detected between the two groups in terms of pre-operative demographics and patients’ characteristics (p>0.05). Clinical results Clinical results of the whole study cohort are demonstrated in table 2 (Table 2). The 2 groups demonstrated a significant improvement from pre- to post-op ROM and functional results (Table 3). A comparison between the two groups demonstrated no significant differences with regard to ROM, functional and subjective scores with the exception of postoperative VAS score pain in favor of group A (0.1 vs 1.9; p=0.004) (Table 2). Regarding patients’ satisfaction, for group A 8 patients were very satisfied (VS), and 2 satisfied, and in group B 7 VS, 2 satisfied, and 1 fair (revision RSA for dislocation). The postoperative radiographic findings did not show evidence of scapular notching with this lateralized RSA at final follow-up. With regard to the glenoid components, we didn’t find any radiolucent lines posteriorly to the base plate or signs of glenoid loosening. The radiographic analysis on the humeral component demonstrated a stress shielding of the greater tuberosity with a partial osteolysis of the medial part of the humerus in 50% of the cases. No evidence of radiolucent lines around the diaphyseal stem and no humeral loosening were detected in the study cohort at the final follow up. All culture specimens were negative. Complications and revision surgeries No complications were noted in group A. One complication was noted in group B with a postoperative dislocation of the RSA that necessitated open reduction and revision surgery. Discussion The principal findings of this study confirm RSA as a treatment modality for failed ATSA, as the entire cohort displayed improved functional outcomes and reduced postoperative pain. However, primary use of a convertible MB ATSA or cemented PE TSA implants did not influence post RSA ROM and functional outcome. Reduced pain levels in favor of the MB group was the only difference in outcomes between the MB and PE implants. An additional finding in this series was that no baseplate was found to be loose, and none needed removal when the primary glenoid component was an uncemented ΜΒ baseplate. Finally, one patient in the revised PE CG group, showed RSA instability and required further revision surgery. These results have significance due to the increasing need for revision of previously implanted anatomical prostheses. Previous studies reported that failed ATSA revised by RSA resulted in improved postoperative ROM, functional outcomes, and pain score at an early and midterm follow up [ 5 , 7 , 8 , 11 , 12 , 19 – 21 ]. On the other hand, the use of ATSA component revisions or soft tissue reconstructions procedures for failed ATSA resulted in poor final outcomes [ 19 , 22 ]. These results are in line with the results of the current study suggesting RSA to be the treatment of choice in case of failed ATSA. However, no studies have presented the results after revision of failed ATSA with RSA with respect to the glenoid implant type that was used in primary ATSA although some of these previous studies included both all-polyethylene cemented and metal-backed glenoid components [ 7 , 20 ]. Τhe revision reasons for MB and cemented PEs are different from each other. In our series the most common reason for ATSA revision was instability in the MB group (group A) and glenoid loosening in the PE cemented group (group B). Except from this difference in etiology, also difference in time of revision was noted. The time from primary ATSA to revision was much shorter in group A than in group B. This can be explained by the difference in etiology for revision between the 2 groups. For the MB the commonest cause of revision was instability that is usually the result of malposition (either too much retroversion with posterior dislocation or too much anteversion with rupture of the subscapularis tendon, or too overstuffed prosthesis with superior migration and rupture of the supraspinatus). Finally, there was a difference in the proportion of primary ATSAs revised according to glenoid implant type: 20% of primary ATSAs with MB glenoid implant type were revised at short term (mean 28.3 months after primary ATSA) whereas 6.3% of primary ATSA with PE cemented glenoid implant were revised at mid or long term (mean 72.7 months). These discrepancies are explained from the different etiology for revision, which in turn may relate to the different indications for primary ATSA. The MB is preferred in cases with cysts in glenoid, in cases that a glenoid type B1 or B2 has to be corrected, and in case of rheumatoid arthritis. While revising these patients with instability of group A (MB), most of them were posteriorly unstable but no posterior erosion of the PE glenoid insert was noted in contrast to the revision of group B (PE), indicating that in this group A with early revision, the problem was not a PE wear contrary to the group B where the main etiology is the PE wear with a glenoid loosening. For group A (MB) the instability as etiology for revision was the result of mechanical factors related to the implantation of primary prosthesis and is usually not time dependent. Such factors were malpostitioning of the implants (excessive retroversion or correction), and oversized implant with an increase of lateral offset with a consequence a secondary rotator cuff rupture (posterosuperior rotator cuff or subscapularis). The resultant muscular imbalance further deteriorates the instability. These factors may also be related to the reason for primary ATSA. Previous reports have also suggested that the problem of glenoid component failure continues undiminished [ 23 ]. In a recent large epidemiology study, glenoid loosening was the main reason for revising an ATSA and occurred in the long term (mean 99 months) whereas ATSA revision for instability occurred at mean 47 months [ 4 ]. Similarly, Gauci et al in their long-term study, noted that although there can be multiple concomitant indications for revision of ATSA because the failure is often multifactorial, their primary indications were loosening in the PE group and dysfunction of the rotator cuff and/or instability in the MB group, which are similar to the indications of the current study [ 24 ]. Other reports, showed that the instability, can be a combination of mechanical failure and rotator cuff deficiency [ 7 , 25 ]. In this content RSA can address the instability caused by soft tissue deficiency through the semi-constrained prosthesis design and the lateralization that increases compressive forces of the deltoid (wrap around angle) and the remaining cuff. Another difference between the two groups in the current study is that although the functional results were similar, the revision procedure and implantation of MB baseplate is much more difficult in cases with bone defect after PE loosening (group B). It has been reported that full PE glenoid loosening in failed ATSA is usually associated with glenoid bone stock deficiencies which increase the difficulty of implanting an RSA during revision and may result in re-revision rate for persistent glenoid loosening up to 22% and an overall 30% complication rate [ 20 ]. The difficulty of addressing the bone defect when revising an ATSA to RSA due to glenoid loosening is intensified due to the lack of preoperative planification and software dedicated to revision cases, and in these cases the experience of the surgeon is important. In the current series, there were 3 cases with bone loss in the PE group that were treated with cancellous bone grafting and implantation of a long-peg MB baseplate during revision to RSA. This resulted in successful outcome 2 years postoperatively. On the contrary no loosening of MB glenoid implants of primary ATSA was noted in this series. It is generally suggested that bone loss can be addressed in a one-stage revision if the anterior and posterior wall are spared, 10mm of the central peg/screw for the glenoid component is contained within the native bone, and the glenoid allograft is supported at least 70% of its circumference by the native glenoid vault [ 26 ]. In absence of these conditions, glenoid reconstruction with allograft in a 3-month staged protocol is advised [ 25 ]. Cases with primary ATSA with PE glenoid implant are more likely to require structural bone graft during revision to RSA compared to MB primary glenoid implants that usually require either nonstructural or no bone graft at all [ 7 ]. Previous reports noted that although it is important to have available bone grafts during cases of revision ATSA to RSA, the advent of augmented glenoid baseplate components and enhanced fixation techniques may decrease the need for grafting [ 5 ]. In the current study, the design of the MB allows to do a lateralization of the center of rotation of 8.5 mm and concomitantly decreases the size and the frequency of the bone graft needed. The shape and the metallic lateralization of the baseplate implant type explains the low frequency of the bone graft required during revision of ATSA with PE to an RSA [ 27 ]. An inferior tilt of the MB glenoid component and perforation of the anterior fossa of the scapula improves the press fit of the base plate, increases the compression forces for a better healing of the bone graft and decreases the negative effect of shearing forces. (FIGURE 4 ). The lateralization of the humeral stem (cut angle 135°, onlay system and the shape of the humeral stem) combined with a lateralized center of rotation prevent the glenoid notching. No intraoperative complications occurred in the current series. The availability of the new convertible platform systems that allow stem and/or baseplate retention can decrease component extraction-related complications [ 9 , 10 , 14 , 15 ]. In the current study the humeral stem was changed in seven cases of which 4 were because it had been placed too high, and this is a relative disadvantage of an onlay system. In most of the cases (six out of seven), release of the soft tissue and cancellous bone around the proximal part facilitated the humeral stem removal without any corticotomy. Postoperative complication rate has been reported ranging between 7–50% and carry significant morbidity that leads to reoperation rate ranging 0–24% [ 5 , 7 , 9 , 12 – 14 , 20 , 28 – 31 ]. Postoperative complications may include scapular stress fracture, periprosthetic fracture, postoperative dislocation, persistent baseplate loosening, glenosphere dissociation, instability, infection, and painful hardware [ 5 , 7 , 20 ]. By using Kaplan-Meier analysis Seth et al showed 89% survival rate at 2 years and 30% survival rate at 5 years for the RSA used for revision of ATSA [ 5 ]. In the current study one patient was re-operated for RSA instability in the PE group while 19/20 RSA implants survived at mean 60 months follow up. Limitations of the study include the retrospective nature of the study and the small sample size. However, there are very few studies in the literature that have compared the results after ATSA revision to RSA with regards to primary ATSA glenoid implant type. Another limitation is the mid-term follow up. Long term follow-up studies would possibly reveal any differences for the RSA implant survival between MB and PE groups. Finally, the study groups displayed variable diagnoses for primary ATSA procedure and showed different reasons for revision to RSA. Despite these limitations, our series is one of the very few that compared the outcomes after failed ATSA conversion to RSA with respect to primary ATSA glenoid implant type. A single surgeon performed all the operations and a single examiner performed the final evaluation of the patients. As a conclusion, revision of a failed ATSA in RSA results in a functional shoulder with minimal pain. The convertibility of the glenoid implant technically facilitates the revision of a failure of ATSA in RSA and postoperatively patients with a prior convertible prosthesis showed reduced pain. However, no differences in ROM and functional outcomes were noted between convertible MB and cemented PE implants. Conclusions ATSA to RSA conversion resulted in improved functional outcomes. Post RSA motion and functional outcomes did not differ between convertible MB ATSA or cemented PE TSA implants with exception of reduced pain levels for patients treated with a convertible MB ATSA system. Abbreviations ATSA, anatomic total shoulder arthroplasty RSA, Reverse shoulder arthroplasty PE, polyethylene MB, metal-backed ROM, range of motion PE CG, PE cemented glenoid CMS, Constant–Murley score SSV, subjective shoulder value SST, Simple Shoulder Test FE, forward elevation ER1, external rotation with the arm at the side ER2, external rotation in 90º of abduction IR, internal rotation VAS, visual analogue scale CT, computed tomography VS, very satisfied Declarations Ethics approval and consent to participate All experimental protocols were approved by institutional Sante Cite ethics committee IRB accreditation: 0990-0279, Approval number: IRB_ADENE_20240602. No informed consent to participate was obtained from the participants in the study. This study was classified as observational (non-interventional) by Sante Cite ethics committee. Statutory and ethical obligations of observational (non-interventional) studies in France: According to the past Huriet law on biomedical research, and to the current regulation that went into effect in August 2006 (law n°2004-806), such studies do not require written consent. This observational research on data fulfils current French regulatory and ethical obligations. Consent for publication Not applicable Availability of data and materials The datasets used and/or analysed during the current study are available from the corresponding author on reasonable request Competing interests Authos PV: FH orthopaedics; receive royalties Authors FZ, EK, AG: The authors declare that they have no competing interests Funding Not applicable Authors' contributions FZ made substantial contributions to the design of the work, the analysis and interpretation of data; has drafted the work and substantively revised it. PV has made substantial contributions to the conception and design of the work; the acquisition, analysis, and interpretation of data; has drafted the work and substantively revised it EK and AG have made substantial contributions to the acquisition, analysis, and interpretation of data and have substantively revised the work All authors have approved the submitted version; All authors have agreed both to be personally accountable for the author's own contributions and to ensure that questions related to the accuracy or integrity of any part of the work, even ones in which the author was not personally involved, are appropriately investigated, resolved, and the resolution documented in the literature. Acknowledgements The authors acknowledge the contribution of INT to the statistical analysis of data. References Hill JM, Norris TR. Long-term results of total shoulder arthroplasty following bone-grafting of the glenoid. J Bone Joint Surg Am. 2001;83–A(6):877–83. 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Sirveaux F, Favard L, Oudet D, Huquet D, Walch G, Mole D. Grammont inverted total shoulder arthroplasty in the treatment of glenohumeral osteoarthritis with massive rupture of the cuff. Results of a multicentre study of 80 shoulders. J Bone Joint Surg Br. 2004;86:388–95. 10.1302/0301-620X.86B3.14024 . Dines JS, Fealy S, Strauss EJ, Allen A, Craig EV, Warren RF, et al. Outcomes analysis of revision total shoulder replacement. J Bone Joint Surg Am. 2006;88:1494–500. 10.2106/JBJS.D.02946 . Melis B, Bonnevialle N, Neyton L, Levigne C, Favard L, Walch G, et al. Glenoid loosening and failure in anatomical total shoulder arthroplasty: is revision with a reverse shoulder arthroplasty a reliable option? J Shoulder Elb Surg. 2012;21:342–9. https://doi.org/10.1016/j.jse.2011.05.021 . Sajadi KR, Kwon YW, Zuckerman JD. Revision shoulder arthroplasty: an analysis of indications and outcomes. J Shoulder Elb Surg. 2010;19:308–13. http://dx.doi.org/10.1016/j.jse.2009.05.016 . Antuna SA, Sperling JW, Cofield RH, Rowland CM. Glenoid revision surgery after total shoulder arthroplasty. J Shoulder Elb Surg. 2001;10:217–24. 10.1067/mse.2001.113961 . Papadonikolakis A, Neradilek MB, Matsen FA 3rd. Failure of the glenoid component in anatomic total shoulder arthroplasty: a systematic review of the English-language literature between 2006 and 2012. J Bone Joint Surg Am. 2013;95(24):2205-12. 10.2106/JBJS.L.00552 . PMID: 24352774. Gauci MO, Bonnevialle N, Moineau G, Baba M, Walch G, Boileau P. Anatomical total shoulder arthroplasty in young patients with osteoarthritis: all-polyethylene versus metal-backed glenoid. Bone Joint J. 2018;100–B(4):485–92. 10.1302/0301-620X.100B4.BJJ-2017-0495.R2 . PMID: 29629579; PMCID: PMC6503758. Wiesel BB, Williams GR. The reverse prosthesis for failed anatomic shoulder arthroplasty. In: Cofield RH, Sperling JW, editors. Revision and complex shoulder arthroplasty. Philadelphia: Lippincott Williams & Wilkins; 2010. p.237 – 49. Klein SM, Dunning P, Mulieri P, Pupello D, Downes K, Frankle MA. Effects of acquired glenoid bone defects on surgical technique and clinical outcomes in reverse 534 shoulder arthroplasty. J Bone Joint Surg Am. 2010;92:1144–54. 10.2106/JBJS.I.00778 . Valenti P, Sekri J, Kany J, Nidtahar I, Werthel JD. Benefits of a metallic lateralized baseplate prolonged by a long metallic post in reverse shoulder arthroplasty to address glenoid bone loss. Int Orthop. 2019;43(9):2131–9. 10.1007/s00264-018-4249-4 . Epub 2018 Nov 30. PMID: 30506090. Abdel MP, Hattrup SJ, Sperling JW, Cofield RH, Kreofsky CR, Sanchez- Sotelo J. Revision of an unstable hemiarthroplasty or anatomical total shoulder replacement using a reverse design prosthesis. Bone Joint J. 2013;95–B:668–72. http://dx.doi.org/10.1302/0301-620X.95B5.30964 . Kelly JDII, Zhao JX, Hobgood ER, Norris TR. Clinical results of revision shoulder arthroplasty using the reverse prosthesis. J Shoulder Elb Surg. 2012;21:1516–25. http://dx.doi.org/10.1016/j.jse.2011.11.021 . Ortmaier R, Resch H, Matis N, Blocher M, Auffarth A, Mayer M, et al. Reverse shoulder arthroplasty in revision of failed shoulder arthroplasty—outcome and follow-up. Int Orthop. 2013;37:67–75. http://dx.doi.org/10.1007/s00264-012-1742-z . Wall B, Nové-Josserand L, O’Connor DP, Edwards TB, Walch G. Reverse total shoulder arthroplasty: a review of results according to etiology. J Bone Joint Surg Am. 2007;89:1476–85. http://dx.doi.org/10.2106/JBJS.F.00666 . Tables Table 1. Patients’ characteristics Variable No or average (range) Total population (n=20) Group A (MB, n=10) Group B (PE CG, n=10) Male/female 8/12 4/6 4/6 Age at revision surgery (years) 66.6 (39-92) 70.3 (60-82) 63.3 (39-92) Surgical site, right/left 12/8 7/4 5/4 Dominant/non dominant 12/8 7/4 5/4 Follow-up (months) 60 (24-188) 50 (24-90) 60.1 (24-188) Time from ATSA to RSA (months) 51.6 (0-155) 28.3 (0-93) 72.7 (0-155) Reasons for ATSA Glenohumeral arthritis, n=9 PE glenoid loosening of previous TSA, n=1 Glenohumeral arthritis, n=7 Instability arthropathy, n=1 Failed resurfacing arthroplasty with glenoid dysplasia, n=1 PHF malunion, n=1 Reasons for ATSA revision Prothesis instability, n=6 Rupture or non-functional PS RC, n=2 Mechanical dissociation of the PE insert, n=1 SSC rupture, n=1 Glenoid loosening, n=6 1/7 concomitant SSC rupture 1/7 concomitant stiffness PS RC rupture, n=2 Dislocation, n=1 (bad quality SSC) Painful stiffness, n=1 MB, metal-backed ; PE, polyethylene; CD, cemented-glenoid; ATSA, anatomic total shoulder arthroplasty; RSA, reverse shoulder arthroplasty; PHF, proximal humerus fracture; PS RC, posterosuperior rotator cuff; SSC, subscapularis Table 2. Clinical and functional outcomes n=20 PREOP POSTOP p Constant-Murley score 34 (16-58) 71.6 (49-89) <0.001 Gain CMS 37 VAS score 6.3 (4-9) 1 (0-7) <0.001 FE (deg) 101.6 (30-160) 150.5 (100-180) <0.001 ER1 (deg) 19 (-30– 60) 40.5 (20-70) <0.001 ER2 (deg) 39 (0-90) 66.3 (30-90) <0.001 IR (points) 3.9 (2-6) 6.4 (2-10) <0.001 Strength (x/25) 4.9 (0-16) 8.2 (2-16) 0.018 SST 3.5 (1-6) 9.2 (8-12) 0.002 SSV 33.3 (20-50) 79.5 (50-100) <0.001 CMS, Constant Murley Score; VAS, visual analogue scale for pain; PREOP, preoperatively; POSTOP, postoperatively; FE, forward elevation; ER1, external rotation with arm at 0 degrees of abduction (arm at side of the body); ER2, external rotation with arm at 90 degrees of abduction; IR, internal rotation; SST; simple shoulder test; SSV, subjective shoulder value Table 3. Outcomes depending on the primary TSA implant type Group A (MB TSA, n=10) Group B (PE CG, n=10) Between groups comparison postoperative PREOP POSTOP p PREOP POSTOP p p Constant-Murley score 35.7 (16-58) 71.5 (55-85) <0.001 32.3 (21-45) 71.8 (49-89) <0.001 0.863 Gain CMS 35.8 38.2 0.73 VAS score 5.9 (4-9) 0.1 (0-1) <0.001 6.6 (4-8) 1.9 (0-7) <0.001 0.004 FE (deg) 94.4 (30-160) 154.4 (120-170) 0.004 108 (80-140) 147 (100-180) 0.003 0.661 ER1 (deg) 16 (-30–40) 37.8 (20-70) <0.001 22 (-30 – 60) 43 (30-70) 0.012 0.447 ER2 (deg) 36 (0-70) 71.1 (40-90) 0.001 42 (10-90) 62 (30-90) 0.06 0.447 IR (points) 4.2 (2-6) 6.4 (4-8) 0.028 3.6 (2-6) 6.4 (2-10) 0.012 0.931 Strength (kg) 4.6 (0-6) 6.8 (2-12) 0.17 5.2 (0-12) 9.7 (3-16) 0.07 0.222 SST 3.5 (1-6) 9.2 (8-12) 0.002 3.3 (1-5) 7.6 (2-10) 0.041 0.432 SSV 34 (20-50) 82.2 (60-90) 0.000 32.5 (20-50) 77 (50-100) 0.000 0.315 Satisfaction 8 VS, 2S 7 VS, 2S, 1 fair 0.587 Complications none 1 reoperation for instability MB TSA, metal-backed total shoulder arthroplasty; PE CG, Polyethylene cemented glenoid implant; CMS, Constant Murley Score; VAS, visual analogue scale for pain; PREOP, preoperatively; POSTOP, postoperatively; FE, forward elevation; ER1, external rotation with arm at 0 degrees of abduction (arm at side of the body); ER2, external rotation with arm at 90 degrees of abduction; IR, internal rotation; SST; simple shoulder test; SSV, subjective shoulder value; VS, very satisfied; S, satisfied. Additional Declarations Competing interest reported. Author PV: FH orthopaedics; receive royalties Authors FZ, EK, AG: The authors declare that they have no competing interests Cite Share Download PDF Status: Posted Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-4296824","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":331859759,"identity":"7e234072-02b2-4179-8595-71bef16a2015","order_by":0,"name":"Frantzeska Zampeli","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA00lEQVRIiWNgGAWjYBAC9gYwZcHDD6ISCojQwnMATEnwSIL0JhiQoIXBAMwgSgv/4aebCyokZIzPr0788MCAQZ5f7AABLQzHzG7POCPBY3bj7WYJoMMMZ85OwK/FnrHB7DZvG0jL2Q0gLQkGtwlo4WFm/3ab958Ej/GMs5t/EKeFjQdoS4MEjwF/7zYibeHhKbs945gEj8QN3m0WCQYShP3Cw3982+2CGht7/v6zm2/+qLCR55cmoAUEmMGkBFilBGHlCC38B4hTPQpGwSgYBSMPAABAjT7bZ7hpNwAAAABJRU5ErkJggg==","orcid":"","institution":"Hand, Upper Limb \u0026 Microsurgery Department, KAT Attica General Hospital, Kifisia","correspondingAuthor":true,"prefix":"","firstName":"Frantzeska","middleName":"","lastName":"Zampeli","suffix":""},{"id":331859760,"identity":"de636349-5ee1-46a3-a5fe-35e657dea1d7","order_by":1,"name":"Efi Kazum","email":"","orcid":"","institution":"Division of Orthopaedic Surgery, Tel Aviv Sourasky Medical Center, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv","correspondingAuthor":false,"prefix":"","firstName":"Efi","middleName":"","lastName":"Kazum","suffix":""},{"id":331859761,"identity":"18c1b145-ebd2-454d-9baf-fba0584abdbf","order_by":2,"name":"Alejandro Gomez","email":"","orcid":"","institution":"Paris shoulder unit, Clinique Bizet, Paris","correspondingAuthor":false,"prefix":"","firstName":"Alejandro","middleName":"","lastName":"Gomez","suffix":""},{"id":331859762,"identity":"becacb32-fa86-4cdf-8928-252094843a1e","order_by":3,"name":"Philippe Valenti","email":"","orcid":"","institution":"Paris shoulder unit, Clinique Bizet, Paris","correspondingAuthor":false,"prefix":"","firstName":"Philippe","middleName":"","lastName":"Valenti","suffix":""}],"badges":[],"createdAt":"2024-04-20 09:29:17","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-4296824/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-4296824/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":62136690,"identity":"93538a49-f2d2-4e3f-8faa-4e77b57397c2","added_by":"auto","created_at":"2024-08-09 16:27:46","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":895341,"visible":true,"origin":"","legend":"\u003cp\u003eAnatomic total shoulder arthroplasty with cementless metal-backed (MB) baseplate glenoid implant revised with reverse shoulder arthroplasty (RSA) for anterior dislocation with subscapularis rupture\u003c/p\u003e\n\u003cp\u003ea. Anteroposterior shoulder radiograph of 72-year-old female patient (group A), operated 2 years ago for centered osteoarthritis of the right shoulder with convertible cementless MB glenoid component shows anterior dislocation. For this component the baseplate with a convex back covered with hydroxyapatite, a central keel and an anterior winglet was fixed with two cortical divergent screws. A 4mm thickness polyethylene was impacted into the baseplate. A long peg was preferred for this small glenoid with osteoporotic bone\u003c/p\u003e\n\u003cp\u003eb. Revision to RSA was made with baseplate and humeral stem retention\u003c/p\u003e","description":"","filename":"1.png","url":"https://assets-eu.researchsquare.com/files/rs-4296824/v1/4b8ea78f9f532e2977370f76.png"},{"id":62135664,"identity":"7ba64c61-7df8-4581-a566-f4759a298ad0","added_by":"auto","created_at":"2024-08-09 16:19:46","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":64854,"visible":true,"origin":"","legend":"\u003cp\u003eAnatomic total shoulder arthroplasty with polyethylene cemented glenoid (PE CG) component with glenoid loosening and glenoid bone defect\u003c/p\u003e\n\u003cp\u003ea. Anteroposterior shoulder radiograph of 65-year-old female patient (group B), operated 11 years ago for centered osteoarthritis of left shoulder with PE CG component showing superior subluxation of the humeral head\u003c/p\u003e\n\u003cp\u003eb. Axial CT images of left shoulder showing loosening of the polyethylene glenoid component with medialization of the humeral head\u003c/p\u003e","description":"","filename":"2.png","url":"https://assets-eu.researchsquare.com/files/rs-4296824/v1/fe88dcd6c39841ef29019f45.png"},{"id":62135667,"identity":"6c1c50e6-3c5b-4951-8cfa-9d48d9840c55","added_by":"auto","created_at":"2024-08-09 16:19:46","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":256401,"visible":true,"origin":"","legend":"\u003cp\u003eSame patient with figure 2. Anteroposterior (left image) and lateral (right image) left shoulder radiograph after revision of anatomic total shoulder arthroplasty (polyethylene cemented glenoid component) with reverse shoulder arthroplasty with long peg and cancellous bone autograft placed superiorly respectively to the coracoid process. The long peg into the native bone with an inferior tilt of the baseplate decrease the shearing forces and allow to obtain a good fixation of the glenoid component and bone graft healing. The humeral stem was removed after a cortical osteotomy of the metaphyseal part. A new cemented humeral stem was placed lower to facilitate the reduction of the prosthesis. A wire cerclage allowed the fixation of the humerus.\u003c/p\u003e","description":"","filename":"Figure3.png","url":"https://assets-eu.researchsquare.com/files/rs-4296824/v1/2e8d0873c6605ac5c1c1c73f.png"},{"id":62135665,"identity":"50a5288f-fa2c-48e0-b879-647fbc407e2b","added_by":"auto","created_at":"2024-08-09 16:19:46","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":28908,"visible":true,"origin":"","legend":"\u003cp\u003eIn the case of a primary ATSA with polyethylene cemented glenoid implant loosening its replacement with a metal-backed (MB) glenoid component was performed in this series. After removing the PE CG component and cement, glenoid defects should be assessed. A metallic long-peg baseplate was used in six cases with 10 mm into the native bone. Inferior tilt and perforation of the anterior fossa of the scapula improved the press fit of the base plate. The shape and the lateralization of the metal back glenoid component (thickness 8.5 mm) allowed to decrease the necessity, or the amount of bone graft needed. The metallic long peg improves the primary stability of the glenoid component in glenoid deficiency. The base plate should have a primary stability before putting bone graft\u003c/p\u003e","description":"","filename":"Figure4.png","url":"https://assets-eu.researchsquare.com/files/rs-4296824/v1/c6a9a70191a56ca05e77b3fb.png"},{"id":75919481,"identity":"555d970d-0596-44f8-b9de-b7a7d9811a21","added_by":"auto","created_at":"2025-02-10 14:09:11","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":2736481,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-4296824/v1/4d1fccf3-b18b-4cf2-b00e-b8eda67082fa.pdf"}],"financialInterests":"Competing interest reported. Author PV: FH orthopaedics; receive royalties\nAuthors FZ, EK, AG: The authors declare that they have no competing interests","formattedTitle":"Outcomes after revision of anatomic total shoulder arthroplasty to reverse shoulder arthroplasty and comparison between cemented or metal-backed glenoid in platform systems.","fulltext":[{"header":"Background","content":"\u003cp\u003eFailed anatomic total shoulder arthroplasty (ATSA) is an intriguing challenge for the orthopedic surgeon. The main causes that lead to ATSA failure and necessitate a revision surgery consist of glenoid loosening, prosthesis instability, rotator cuff tear, periprosthetic fracture, infection, implant failure and deltoid muscle dysfunction [\u003cspan additionalcitationids=\"CR2\" citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e]. In addition, loss of humeral and glenoid bone stock, soft tissue compromise, and complications related to the failed prosthesis, render the restoration of a stable and functional joint highly difficult [\u003cspan additionalcitationids=\"CR5 CR6\" citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eGlenoid loosening forms the weakest link in ATSA long-term survival and is often the reason for implant\u0026rsquo;s failure. Reverse shoulder arthroplasty (RSA) has been considered as the treatment of choice for failed ATSA cases, especially when associated with loss of glenoid bone stock or with an irreparable rotator cuff lesion [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e]. However, ATSA\u0026rsquo;s cemented polyethylene (PE) implant removal may aggravate the glenoid bone defect and render implantation of the metal back of an RSA difficult [\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e]. According to reports, the use of a convertible total shoulder arthroplasty system with a convertible glenoid implant, technically facilitates ATSA to RSA conversion [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e, \u003cspan additionalcitationids=\"CR9 CR10 CR11 CR12 CR13\" citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e]. Such convertible platform systems allow for reductions in revisions\u0026rsquo; duration time and associated complications by avoiding humeral stem and/or glenoid metal-backed (MB) component replacement [\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e, \u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e, \u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e, \u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eThe purpose of this study was to report the outcomes of ATSA to RSA revision surgeries and to compare patients\u0026rsquo; clinical outcomes depending on the primary ATSA glenoid implant type, cemented PE versus a convertible MB. The primary hypothesis was that post RSA patients will demonstrate improved range of motion (ROM) and functional outcomes. Secondary hypothesis was that the clinical outcomes would differ between patients treated with ATSA with PE and MB implants in favor of the platform system.\u003c/p\u003e"},{"header":"Methods","content":"\u003cp\u003ePatients\u0026rsquo; selection\u003c/p\u003e\n\u003cp\u003eBetween 2008 and 2018, 208 ATSAs were performed at a single institution. Among these, 20 patients underwent revision of failed ATSA with RSA. Primary and revision procedures were performed by the senior author (PV) and were available for follow up. The patients\u0026rsquo; characteristics are described in table 1. (Table 1) Patients\u0026rsquo; inclusion criteria consisted of 1) ATSA to RSA revision surgeries using a completely convertible RSA implant and 2) minimal clinical follow-up of 2 years. Exclusion criteria consisted of 1) revision of full PE of ATSA to a metal-backed ATSA (one case), 2) revision of full PE cemented ATSA to an hemiarthoplasty (one case), 3) deltoid palsy, 4) prosthetic infection, 5) revision with additional soft tissue procedure (3 cases).\u003cem\u003e\u0026nbsp;\u003c/em\u003e\u003c/p\u003e\n\u003cp\u003eThis study was classified as observational (non-interventional) by our local ethics committee. Statutory and ethical obligations of observational (non-interventional) studies in our country: According to the past Huriet law on biomedical research, and to the current regulation that went into effect in August 2006 (law n\u0026deg;2004-806), such studies do not require prior submission or approval to/from an IRB, and they do not require written consent. This observational research on data fulfils current local regulatory and ethical obligations.\u003c/p\u003e\n\u003cp\u003eThe study cohort was divided into two groups based on the glenoid implant type that was used at the primary ATSA procedure. Group A (10 cases) consisted of failed ATSAs that were primarily treated with MB glenoid convertible implant (FIGURE 1) and group B (10 cases) represented failed\u0026nbsp;\u0026Alpha;TSA treated primarily with PE cemented glenoid (PE CG) implants (FIGURE 2). Data regarding the etiologies for primary\u0026nbsp;\u0026Alpha;TSA surgeries and revision RSA surgeries are summarized in Table 1 (Table 1).\u003c/p\u003e\n\u003cp\u003eFor the primary ATSAs a convertible shoulder prosthesis (Arrow; FH Orthopedics, Mulhouse, France) that facilitates ATSA to RSA revision surgeries was used for most of the cases (FIGURE 1). The system offers a universal humeral stem and either a MB glenoid convertible or a cemented full PE glenoid implant. The MB component was preferred by the senior author if there are cysts in the glenoid, if there was a B1 or B2 glenoid and in case of rheumatoid arthritis. Conversion to a reverse prosthesis allows the surgeon to replace the humeral head metallic tray (ATSA) with a polyethylene insert (RSA) without removing the humeral stem. In case the glenoid implant is a MB device (all cases in group A), polyethylene shell removal exposes a well-fixed glenoid baseplate, which supports a glenosphere insertion. In 2 cases of group B, the PE cemented glenoid implant was part of ATSA with no convertible platform humeral stem implant (DePuy Synthes, J\u0026amp;J MedTech, MA, USA).\u003c/p\u003e\n\u003cp\u003eSurgical technique and intraoperative findings\u003c/p\u003e\n\u003cp\u003eAll revisions were performed under general anesthesia and interscalene block for a better postoperative pain relief with the patient in a semi beach chair position and the arm in lying position on a support to relax the deltoid. A Reverse Arrow system (FH orthopedics, Mulhouse, France) was implanted in all cases. The previous deltopectoral approach was used, which could also allow for distal extension of the exposure in case of stem replacement. Adhesions at the deep part of the deltoid and the conjoint tendon were carefully released. Previous biceps tenodesis to the aponeurosis of pectoralis major was verified. In case of thin, fibrotic or considered as non-functional rotator cuff tear, or tear of the subscapularis or supraspinatus muscle, or both, causing instability, a conversion from an anatomic to an RSA was performed. When the subscapularis tendon could be retained, it was peeled off from the medial border of the bicipital groove to obtain sufficient length for a tension-free reinsertion. The RSA that was used (Arrow; FH Orthopedics, Mulhouse, France) allows lateralization in both components (glenosphere and humerus) and the subscapularis tendon was frequently medialized during transosseous reinsertion in order to maintain 30\u0026ordm; of external rotation. Before implantation of the new prosthesis five tissue biopsies were collected systematically to search germs even in the absence of local or general infectious signs. The Arrow convertible system is a dual platform system, with a convertibility on both sides (humeral stem and the glenoid MB baseplate). Therefore, the system allows shifting from ATSA to RSA without any humeral stem and/or glenoid MB revision making surgery less demanding, less invasive and less time consuming (FIGURE 1). Nevertheless, the humeral stem had to be revised in cases of loosening or malposition (excessive retroversion/anteversion and/or too proud stem) (FIGURES 2,3). There were 10 cases with MB glenoid component (group A) and 10 cemented PE glenoid components (group B). In group A, the baseplate with a convex back covered with hydroxyapatite, a central keel and an anterior winglet is fixed with two cortical divergent screws. A 4mm thickness polyethylene is impacted into the baseplate. In group B the polyethylene component was pegged (four pegs). During conversion, the anatomic head of the humeral implant was disconnected from the stem and removed. In case of a MB glenoid component, the PE glenoid onlay was removed from the baseplate. No baseplate was loosened, and no baseplate has been removed in this group A (FIGURE 1). In the case of a cemented PE glenoid component, its replacement with a MB glenoid component was performed (FIGURES 2,3). After removing the PE glenoid component and cement, bone defects were reconstructed with cancellous graft (iliac crest bone autograft in one case, synthetic bone graft in one case, and humeral autograft from the humeral re-cut in one case). A metallic long-peg baseplate was used in 6 cases with 10 mm into the native bone. Inferior tilt and perforation of the anterior fossa of the scapula improved the press fit of the base plate. The shape and the lateralization of the metal back glenoid component (thickness 8.5 mm) allowed to decrease the necessity, or the amount of bone graft needed. The metallic long peg (FH orthopedics, Mulhouse, France) improves the primary stability of the glenoid component in glenoid deficiency (FIGURE 4). A glenosphere was impacted on the baseplate. Humeral stems were removed in 7 cases: 5 cases in group A (1 for humeral loosening and 4 to be placed in lower position because the stem was too proud and rendered the RSA irreducible) and 2 cases in group B (the stem was not convertible, DePuy Synthes, J\u0026amp;J MedTech, MA, USA). In all cases except from 1, removal of the stem was possible without osteotomy and, hence, was replaced with a new cemented stem in the correct high. For 1 case (group B) cortical osteotomy of the metaphyseal part was performed to change the humeral stem. A new cemented humeral stem was placed lower to facilitate the reduction of the prosthesis and wire cerclage was used for the fixation of the humerus (FIGURE 3). The metaphyseal part was re-cut and cancellous and chips bone graft allowed to obtain a press fit metaphyseal stem and cement into the diaphysis. A standard polyethylene humeral insert was implanted on the humeral stem in all cases.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003ePostoperative rehabilitation\u003c/p\u003e\n\u003cp\u003eAll the patients were immobilized with a brace in neutral rotation maintained for four weeks. Passive ROM in forward elevation and external rotation begun immediately after the operation until pain limits. Active ROM and hydrotherapy were initiated at 6 weeks post-operatively and muscular strengthening of the external rotators and the depressor muscles represented the last step of rehabilitation that was initiated 3 months post-operatively.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003ePatient assessment\u003c/p\u003e\n\u003cp\u003ePre- and post-operative clinical evaluation was performed by the senior author and included evaluation of functional scores: absolute Constant\u0026ndash;Murley score (CMS), subjective shoulder value (SSV), Simple Shoulder Test (SST) and active ROM assessment including forward elevation (FE) at scapular level, external rotation with the arm at the side (ER1), external rotation in 90\u0026ordm; of abduction (ER2) and internal rotation (IR). Subjective pain evaluation was recorded with the visual analogue scale (VAS) pain score from one to ten. Strength was measured with the arm in abduction of 90\u0026deg; in the plane of the scapula, with a resistance during five seconds against a hand-held dynamometer fixed at the level of the wrist. In addition, at the last follow up visit patients were asked to evaluate their degree of satisfaction from the final outcome using the following scale: very satisfied, satisfied, or fair. True antero-posterior (neutral, external and internal rotation) and scapular lateral radiographs were routinely performed pre- and post-operatively at the latest follow-up examination. Pre-operative computed tomography (CT) scans were performed to analyze bone deformity, glenoid bone stock, muscle trophicity and degree of fatty infiltration (according to Goutallier classification) [17]. We looked for evidence of glenoid component loosening (radiolucent lines around the PE cemented or the base plate, medialization of the PE component, hardware breakage and migration of base plate or PE) or scapular notching (graded according to the Sirveaux-Nerot classification) [18]. Intra- and post-operative complications were recorded.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eStatistical analysis\u003c/p\u003e\n\u003cp\u003eThe analysis was performed with the statistical battery provided by STATA\u0026reg; (version 11.0 for Mac OS; StataCorp, Texas, USA.). The Shapiro-Wilk test was used to assess the normal distribution of the results, according to the different groups. The Student\u0026rsquo;s t test or Mann\u0026ndash;Whitney test were used to compare the preoperative and postoperative results for all values in the distinct groups, and between groups. Statistical significance was determined at a p-value \u0026lt; 0.05.\u003c/p\u003e"},{"header":"Results","content":"\u003cp\u003eDemographics and patients\u0026rsquo; characteristics per group\u003c/p\u003e\n\u003cp\u003eDuring the study period, 208 ATSAs were performed at our institution, 50 with MB glenoid component and 158 with PE cemented glenoid implant. Twenty patients (12 females) met the inclusion criteria and were evaluated with mean follow-up 60 months (24-188). The patients\u0026rsquo; information for the whole study cohort and for groups A (MB, n=10) and B (PE CG, n=10) are demonstrated in table 1. No significant differences were detected between the two groups in terms of pre-operative demographics and patients\u0026rsquo; characteristics (p\u0026gt;0.05).\u003cem\u003e\u0026nbsp;\u003c/em\u003e\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eClinical results\u003c/p\u003e\n\u003cp\u003eClinical results of the whole study cohort are demonstrated in table 2 (Table 2). The 2 groups demonstrated a significant improvement from pre- to post-op ROM and functional results (Table 3). A comparison between the two groups demonstrated no significant differences with regard to ROM, functional and subjective scores with the exception of postoperative VAS score pain in favor of group A (0.1 vs 1.9; p=0.004) (Table 2).\u0026nbsp;Regarding patients\u0026rsquo; satisfaction, for group A 8 patients were very satisfied (VS), and 2 satisfied, and in group B 7 VS, 2 satisfied, and 1 fair (revision RSA for dislocation).\u003c/p\u003e\n\u003cp\u003eThe postoperative radiographic findings did not show evidence of scapular notching with this lateralized RSA at final follow-up. With regard to the glenoid components, we didn\u0026rsquo;t find any radiolucent lines posteriorly to the base plate or signs of glenoid loosening. The radiographic analysis on the humeral component demonstrated a stress shielding of the greater tuberosity with a partial osteolysis of the medial part of the humerus in 50% of the cases. No evidence of radiolucent lines around the diaphyseal stem and no humeral loosening were detected in the study cohort at the final follow up. All culture specimens were negative.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eComplications and revision surgeries\u003c/p\u003e\n\u003cp\u003eNo complications were noted in group A. One complication was noted in group B with a postoperative dislocation of the RSA that necessitated open reduction and revision surgery.\u003c/p\u003e"},{"header":"Discussion","content":"\u003cp\u003eThe principal findings of this study confirm RSA as a treatment modality for failed ATSA, as the entire cohort displayed improved functional outcomes and reduced postoperative pain. However, primary use of a convertible MB ATSA or cemented PE TSA implants did not influence post RSA ROM and functional outcome. Reduced pain levels in favor of the MB group was the only difference in outcomes between the MB and PE implants. An additional finding in this series was that no baseplate was found to be loose, and none needed removal when the primary glenoid component was an uncemented ΜΒ baseplate. Finally, one patient in the revised PE CG group, showed RSA instability and required further revision surgery. These results have significance due to the increasing need for revision of previously implanted anatomical prostheses.\u003c/p\u003e \u003cp\u003ePrevious studies reported that failed ATSA revised by RSA resulted in improved postoperative ROM, functional outcomes, and pain score at an early and midterm follow up [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e, \u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e, \u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e, \u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e, \u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e, \u003cspan additionalcitationids=\"CR20\" citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e]. On the other hand, the use of ATSA component revisions or soft tissue reconstructions procedures for failed ATSA resulted in poor final outcomes [\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e, \u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e]. These results are in line with the results of the current study suggesting RSA to be the treatment of choice in case of failed ATSA. However, no studies have presented the results after revision of failed ATSA with RSA with respect to the glenoid implant type that was used in primary ATSA although some of these previous studies included both all-polyethylene cemented and metal-backed glenoid components [\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e, \u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eΤhe revision reasons for MB and cemented PEs are different from each other. In our series the most common reason for ATSA revision was instability in the MB group (group A) and glenoid loosening in the PE cemented group (group B). Except from this difference in etiology, also difference in time of revision was noted. The time from primary ATSA to revision was much shorter in group A than in group B. This can be explained by the difference in etiology for revision between the 2 groups. For the MB the commonest cause of revision was instability that is usually the result of malposition (either too much retroversion with posterior dislocation or too much anteversion with rupture of the subscapularis tendon, or too overstuffed prosthesis with superior migration and rupture of the supraspinatus).\u003c/p\u003e \u003cp\u003eFinally, there was a difference in the proportion of primary ATSAs revised according to glenoid implant type: 20% of primary ATSAs with MB glenoid implant type were revised at short term (mean 28.3 months after primary ATSA) whereas 6.3% of primary ATSA with PE cemented glenoid implant were revised at mid or long term (mean 72.7 months). These discrepancies are explained from the different etiology for revision, which in turn may relate to the different indications for primary ATSA. The MB is preferred in cases with cysts in glenoid, in cases that a glenoid type B1 or B2 has to be corrected, and in case of rheumatoid arthritis.\u003c/p\u003e \u003cp\u003eWhile revising these patients with instability of group A (MB), most of them were posteriorly unstable but no posterior erosion of the PE glenoid insert was noted in contrast to the revision of group B (PE), indicating that in this group A with early revision, the problem was not a PE wear contrary to the group B where the main etiology is the PE wear with a glenoid loosening. For group A (MB) the instability as etiology for revision was the result of mechanical factors related to the implantation of primary prosthesis and is usually not time dependent. Such factors were malpostitioning of the implants (excessive retroversion or correction), and oversized implant with an increase of lateral offset with a consequence a secondary rotator cuff rupture (posterosuperior rotator cuff or subscapularis). The resultant muscular imbalance further deteriorates the instability. These factors may also be related to the reason for primary ATSA. Previous reports have also suggested that the problem of glenoid component failure continues undiminished [\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e]. In a recent large epidemiology study, glenoid loosening was the main reason for revising an ATSA and occurred in the long term (mean 99 months) whereas ATSA revision for instability occurred at mean 47 months [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e]. Similarly, Gauci et al in their long-term study, noted that although there can be multiple concomitant indications for revision of ATSA because the failure is often multifactorial, their primary indications were loosening in the PE group and dysfunction of the rotator cuff and/or instability in the MB group, which are similar to the indications of the current study [\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e]. Other reports, showed that the instability, can be a combination of mechanical failure and rotator cuff deficiency [\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e, \u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e]. In this content RSA can address the instability caused by soft tissue deficiency through the semi-constrained prosthesis design and the lateralization that increases compressive forces of the deltoid (wrap around angle) and the remaining cuff.\u003c/p\u003e \u003cp\u003eAnother difference between the two groups in the current study is that although the functional results were similar, the revision procedure and implantation of MB baseplate is much more difficult in cases with bone defect after PE loosening (group B). It has been reported that full PE glenoid loosening in failed ATSA is usually associated with glenoid bone stock deficiencies which increase the difficulty of implanting an RSA during revision and may result in re-revision rate for persistent glenoid loosening up to 22% and an overall 30% complication rate [\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e]. The difficulty of addressing the bone defect when revising an ATSA to RSA due to glenoid loosening is intensified due to the lack of preoperative planification and software dedicated to revision cases, and in these cases the experience of the surgeon is important. In the current series, there were 3 cases with bone loss in the PE group that were treated with cancellous bone grafting and implantation of a long-peg MB baseplate during revision to RSA. This resulted in successful outcome 2 years postoperatively. On the contrary no loosening of MB glenoid implants of primary ATSA was noted in this series.\u003c/p\u003e \u003cp\u003eIt is generally suggested that bone loss can be addressed in a one-stage revision if the anterior and posterior wall are spared, 10mm of the central peg/screw for the glenoid component is contained within the native bone, and the glenoid allograft is supported at least 70% of its circumference by the native glenoid vault [\u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e]. In absence of these conditions, glenoid reconstruction with allograft in a 3-month staged protocol is advised [\u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e]. Cases with primary ATSA with PE glenoid implant are more likely to require structural bone graft during revision to RSA compared to MB primary glenoid implants that usually require either nonstructural or no bone graft at all [\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e]. Previous reports noted that although it is important to have available bone grafts during cases of revision ATSA to RSA, the advent of augmented glenoid baseplate components and enhanced fixation techniques may decrease the need for grafting [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e]. In the current study, the design of the MB allows to do a lateralization of the center of rotation of 8.5 mm and concomitantly decreases the size and the frequency of the bone graft needed. The shape and the metallic lateralization of the baseplate implant type explains the low frequency of the bone graft required during revision of ATSA with PE to an RSA [\u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e]. An inferior tilt of the MB glenoid component and perforation of the anterior fossa of the scapula improves the press fit of the base plate, increases the compression forces for a better healing of the bone graft and decreases the negative effect of shearing forces. (FIGURE \u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e). The lateralization of the humeral stem (cut angle 135\u0026deg;, onlay system and the shape of the humeral stem) combined with a lateralized center of rotation prevent the glenoid notching.\u003c/p\u003e \u003cp\u003eNo intraoperative complications occurred in the current series. The availability of the new convertible platform systems that allow stem and/or baseplate retention can decrease component extraction-related complications [\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e, \u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e, \u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e, \u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e]. In the current study the humeral stem was changed in seven cases of which 4 were because it had been placed too high, and this is a relative disadvantage of an onlay system. In most of the cases (six out of seven), release of the soft tissue and cancellous bone around the proximal part facilitated the humeral stem removal without any corticotomy. Postoperative complication rate has been reported ranging between 7\u0026ndash;50% and carry significant morbidity that leads to reoperation rate ranging 0\u0026ndash;24% [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e, \u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e, \u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e, \u003cspan additionalcitationids=\"CR13\" citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e, \u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e, \u003cspan additionalcitationids=\"CR29 CR30\" citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e31\u003c/span\u003e]. Postoperative complications may include scapular stress fracture, periprosthetic fracture, postoperative dislocation, persistent baseplate loosening, glenosphere dissociation, instability, infection, and painful hardware [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e, \u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e, \u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e]. By using Kaplan-Meier analysis Seth et al showed 89% survival rate at 2 years and 30% survival rate at 5 years for the RSA used for revision of ATSA [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e]. In the current study one patient was re-operated for RSA instability in the PE group while 19/20 RSA implants survived at mean 60 months follow up.\u003c/p\u003e \u003cp\u003eLimitations of the study include the retrospective nature of the study and the small sample size. However, there are very few studies in the literature that have compared the results after ATSA revision to RSA with regards to primary ATSA glenoid implant type. Another limitation is the mid-term follow up. Long term follow-up studies would possibly reveal any differences for the RSA implant survival between MB and PE groups. Finally, the study groups displayed variable diagnoses for primary ATSA procedure and showed different reasons for revision to RSA. Despite these limitations, our series is one of the very few that compared the outcomes after failed ATSA conversion to RSA with respect to primary ATSA glenoid implant type. A single surgeon performed all the operations and a single examiner performed the final evaluation of the patients. As a conclusion, revision of a failed ATSA in RSA results in a functional shoulder with minimal pain. The convertibility of the glenoid implant technically facilitates the revision of a failure of ATSA in RSA and postoperatively patients with a prior convertible prosthesis showed reduced pain. However, no differences in ROM and functional outcomes were noted between convertible MB and cemented PE implants.\u003c/p\u003e"},{"header":"Conclusions","content":"\u003cp\u003eATSA to RSA conversion resulted in improved functional outcomes. Post RSA motion and functional outcomes did not differ between convertible MB ATSA or cemented PE TSA implants with exception of reduced pain levels for patients treated with a convertible MB ATSA system.\u003c/p\u003e"},{"header":"Abbreviations","content":"\u003cp\u003eATSA, anatomic total shoulder arthroplasty\u003c/p\u003e\n\u003cp\u003eRSA, Reverse shoulder arthroplasty\u003c/p\u003e\n\u003cp\u003ePE, polyethylene\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eMB, metal-backed\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eROM, range of motion\u003c/p\u003e\n\u003cp\u003ePE CG, PE cemented glenoid\u003c/p\u003e\n\u003cp\u003eCMS, Constant\u0026ndash;Murley score\u003c/p\u003e\n\u003cp\u003eSSV, subjective shoulder value\u003c/p\u003e\n\u003cp\u003eSST, Simple Shoulder Test\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eFE, forward elevation\u003c/p\u003e\n\u003cp\u003eER1, external rotation with the arm at the side\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eER2, external rotation in 90\u0026ordm; of abduction\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eIR, internal rotation\u003c/p\u003e\n\u003cp\u003eVAS, visual analogue scale\u003c/p\u003e\n\u003cp\u003eCT, computed tomography\u003c/p\u003e\n\u003cp\u003eVS, very satisfied\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003eEthics approval and consent to participate\u003c/p\u003e\n\u003cp\u003eAll experimental protocols were approved by institutional Sante Cite ethics committee IRB accreditation: 0990-0279, Approval number: IRB_ADENE_20240602. No informed consent to participate was obtained from the participants in the study. This study was classified as observational (non-interventional) by Sante Cite ethics committee. Statutory and ethical obligations of observational (non-interventional) studies in France: According to the past Huriet law on biomedical research, and to the current regulation that went into effect in August 2006 (law n\u0026deg;2004-806), such studies do not require written consent. This observational research on data fulfils current French regulatory and ethical obligations.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eConsent for publication\u003c/p\u003e\n\u003cp\u003eNot applicable\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eAvailability of data and materials\u003c/p\u003e\n\u003cp\u003eThe datasets used and/or analysed during the current study are available from the corresponding author on reasonable request\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eCompeting interests\u003c/p\u003e\n\u003cp\u003eAuthos PV: FH orthopaedics; receive royalties\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eAuthors FZ, EK, AG: The authors declare that they have no competing interests \u0026nbsp;\u003c/p\u003e\n\u003cp\u003eFunding\u003c/p\u003e\n\u003cp\u003eNot applicable\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eAuthors\u0026apos; contributions\u003c/p\u003e\n\u003cp\u003eFZ made substantial contributions to the design of the work, the analysis and interpretation of data; has drafted the work and substantively revised it.\u003c/p\u003e\n\u003cp\u003ePV has made substantial contributions to the conception and design of the work; the acquisition, analysis, and interpretation of data; has drafted the work and substantively revised it\u003c/p\u003e\n\u003cp\u003eEK and AG have made substantial contributions to the acquisition, analysis, and interpretation of data and have substantively revised the work\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eAll authors have approved the submitted version;\u003c/p\u003e\n\u003cp\u003eAll authors have agreed both to be personally accountable for the author\u0026apos;s own contributions and to ensure that questions related to the accuracy or integrity of any part of the work, even ones in which the author was not personally involved, are appropriately investigated, resolved, and the resolution documented in the literature.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eAcknowledgements\u003c/p\u003e\n\u003cp\u003eThe authors acknowledge the contribution of INT to the statistical analysis of data.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eHill JM, Norris TR. Long-term results of total shoulder arthroplasty following bone-grafting of the glenoid. J Bone Joint Surg Am. 2001;83\u0026ndash;A(6):877\u0026ndash;83.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSanchez-Sotelo J, et al. Instability after shoulder arthroplasty: results of surgical treatment. J Bone Joint Surg Am. 2003;85\u0026ndash;A(4):622\u0026ndash;31.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eWirth MA, Rockwood CA Jr. Complications of shoulder arthroplasty. Clin Orthop Relat Res 14;307:47\u0026ndash;69.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eGauci MO, Cavalier M, Gonzalez JF, Holzer N, Baring T, Walch G, Boileau P. Revision of failed shoulder arthroplasty: epidemiology, etiology, and surgical options. J Shoulder Elb Surg. 2020;29(3):541\u0026ndash;9. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1016/j.jse.2019.07.034\u003c/span\u003e\u003cspan address=\"10.1016/j.jse.2019.07.034\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e. Epub 2019 Oct 6. PMID: 31594726.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSheth MM, Sholder D, Getz CL, Williams GR, Namdari S. Revision of failed hemiarthroplasty and anatomic total shoulder arthroplasty to reverse total shoulder arthroplasty. J Shoulder Elb Surg. 2019;28(6):1074\u0026ndash;81. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1016/j.jse.2018.10.026\u003c/span\u003e\u003cspan address=\"10.1016/j.jse.2018.10.026\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e. Epub 2019 Feb 1. PMID: 30713064.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eWagner ER, Chang MJ, Welp KM, Solberg MJ, Hunt TJ, Woodmass JM, Higgins LD, Warner JJP. The impact of the reverse prosthesis on revision shoulder arthroplasty: analysis of a high-volume shoulder practice. J Shoulder Elb Surg. 2019;28(2):e49\u0026ndash;56. Epub 2018 Nov 28. PMID: 30503332.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eWalker M, Willis MP, Brooks JP, Pupello D, Mulieri PJ, Frankle MA. The use of the reverse shoulder arthroplasty for treatment of failed total shoulder arthroplasty. 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Int Orthop. 2013;37:1297\u0026ndash;305. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1007/s00264-013-1907-4\u003c/span\u003e\u003cspan address=\"10.1007/s00264-013-1907-4\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eMagosch P, Lichtenberg S, Tauber M, Martetschl\u0026auml;ger F, Habermeyer P. Prospective midterm results of a new convertible glenoid component in anatomic shoulder arthroplasty: a cohort study. Arch Orthop Trauma Surg. 2021;141(5):717\u0026ndash;24. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1007/s00402-020-03454-y\u003c/span\u003e\u003cspan address=\"10.1007/s00402-020-03454-y\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e. Epub 2020 Apr 23. PMID: 32328719.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eMelis B, Bonnevialle N, Neyton N, Walch G, Boileau P. Aseptic glenoid loosening or failure in total shoulder arthroplasty: Results of revision with reverse shoulder arthroplasty. In: Walch G, Boileau P, Mole D, Favard L, Levigne C, Sirveaux F, editors. Shoulder concepts 2010: The glenoid. Paris: Sauramps Medical; 2010. pp. 299\u0026ndash;312.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003ePatel DN, Young B, Onyekwelu I, Zuckerman JD, Kwon YW. Reverse total shoulder arthroplasty for failed shoulder arthroplasty. 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The use of a modular system to convert an anatomical total shoulder arthroplasty to a reverse shoulder arthroplasty: clinical and radiological results. Bone Joint J. 2015;97\u0026ndash;B:1662\u0026ndash;7. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttp://dx.doi.org/10.1302/0301-620X.97B12.35176\u003c/span\u003e\u003cspan address=\"10.1302/0301-620X.97B12.35176\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eKany J, Amouyel T, Flamand O, Katz D, Valenti P. A convertible shoulder system: is it useful in total shoulder arthroplasty revisions? Int Orthop. 2015;39(2):299\u0026ndash;304. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1007/s00264-014-2563-z\u003c/span\u003e\u003cspan address=\"10.1007/s00264-014-2563-z\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e. Epub 2014 Oct 16. 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Grammont inverted total shoulder arthroplasty in the treatment of glenohumeral osteoarthritis with massive rupture of the cuff. Results of a multicentre study of 80 shoulders. J Bone Joint Surg Br. 2004;86:388\u0026ndash;95. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1302/0301-620X.86B3.14024\u003c/span\u003e\u003cspan address=\"10.1302/0301-620X.86B3.14024\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eDines JS, Fealy S, Strauss EJ, Allen A, Craig EV, Warren RF, et al. Outcomes analysis of revision total shoulder replacement. J Bone Joint Surg Am. 2006;88:1494\u0026ndash;500. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.2106/JBJS.D.02946\u003c/span\u003e\u003cspan address=\"10.2106/JBJS.D.02946\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eMelis B, Bonnevialle N, Neyton L, Levigne C, Favard L, Walch G, et al. Glenoid loosening and failure in anatomical total shoulder arthroplasty: is revision with a reverse shoulder arthroplasty a reliable option? J Shoulder Elb Surg. 2012;21:342\u0026ndash;9. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/j.jse.2011.05.021\u003c/span\u003e\u003cspan address=\"10.1016/j.jse.2011.05.021\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSajadi KR, Kwon YW, Zuckerman JD. Revision shoulder arthroplasty: an analysis of indications and outcomes. J Shoulder Elb Surg. 2010;19:308\u0026ndash;13. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttp://dx.doi.org/10.1016/j.jse.2009.05.016\u003c/span\u003e\u003cspan address=\"10.1016/j.jse.2009.05.016\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eAntuna SA, Sperling JW, Cofield RH, Rowland CM. Glenoid revision surgery after total shoulder arthroplasty. J Shoulder Elb Surg. 2001;10:217\u0026ndash;24. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1067/mse.2001.113961\u003c/span\u003e\u003cspan address=\"10.1067/mse.2001.113961\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003ePapadonikolakis A, Neradilek MB, Matsen FA 3rd. Failure of the glenoid component in anatomic total shoulder arthroplasty: a systematic review of the English-language literature between 2006 and 2012. J Bone Joint Surg Am. 2013;95(24):2205-12. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.2106/JBJS.L.00552\u003c/span\u003e\u003cspan address=\"10.2106/JBJS.L.00552\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e. PMID: 24352774.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eGauci MO, Bonnevialle N, Moineau G, Baba M, Walch G, Boileau P. Anatomical total shoulder arthroplasty in young patients with osteoarthritis: all-polyethylene versus metal-backed glenoid. Bone Joint J. 2018;100\u0026ndash;B(4):485\u0026ndash;92. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1302/0301-620X.100B4.BJJ-2017-0495.R2\u003c/span\u003e\u003cspan address=\"10.1302/0301-620X.100B4.BJJ-2017-0495.R2\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e. PMID: 29629579; PMCID: PMC6503758.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eWiesel BB, Williams GR. The reverse prosthesis for failed anatomic shoulder arthroplasty. In: Cofield RH, Sperling JW, editors. Revision and complex shoulder arthroplasty. Philadelphia: Lippincott Williams \u0026amp; Wilkins; 2010. p.237\u0026thinsp;\u0026ndash;\u0026thinsp;49.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eKlein SM, Dunning P, Mulieri P, Pupello D, Downes K, Frankle MA. Effects of acquired glenoid bone defects on surgical technique and clinical outcomes in reverse 534 shoulder arthroplasty. J Bone Joint Surg Am. 2010;92:1144\u0026ndash;54. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.2106/JBJS.I.00778\u003c/span\u003e\u003cspan address=\"10.2106/JBJS.I.00778\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eValenti P, Sekri J, Kany J, Nidtahar I, Werthel JD. Benefits of a metallic lateralized baseplate prolonged by a long metallic post in reverse shoulder arthroplasty to address glenoid bone loss. Int Orthop. 2019;43(9):2131\u0026ndash;9. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1007/s00264-018-4249-4\u003c/span\u003e\u003cspan address=\"10.1007/s00264-018-4249-4\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e. Epub 2018 Nov 30. PMID: 30506090.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eAbdel MP, Hattrup SJ, Sperling JW, Cofield RH, Kreofsky CR, Sanchez- Sotelo J. Revision of an unstable hemiarthroplasty or anatomical total shoulder replacement using a reverse design prosthesis. Bone Joint J. 2013;95\u0026ndash;B:668\u0026ndash;72. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttp://dx.doi.org/10.1302/0301-620X.95B5.30964\u003c/span\u003e\u003cspan address=\"10.1302/0301-620X.95B5.30964\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eKelly JDII, Zhao JX, Hobgood ER, Norris TR. Clinical results of revision shoulder arthroplasty using the reverse prosthesis. J Shoulder Elb Surg. 2012;21:1516\u0026ndash;25. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttp://dx.doi.org/10.1016/j.jse.2011.11.021\u003c/span\u003e\u003cspan address=\"10.1016/j.jse.2011.11.021\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eOrtmaier R, Resch H, Matis N, Blocher M, Auffarth A, Mayer M, et al. Reverse shoulder arthroplasty in revision of failed shoulder arthroplasty\u0026mdash;outcome and follow-up. Int Orthop. 2013;37:67\u0026ndash;75. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttp://dx.doi.org/10.1007/s00264-012-1742-z\u003c/span\u003e\u003cspan address=\"10.1007/s00264-012-1742-z\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eWall B, Nov\u0026eacute;-Josserand L, O\u0026rsquo;Connor DP, Edwards TB, Walch G. Reverse total shoulder arthroplasty: a review of results according to etiology. J Bone Joint Surg Am. 2007;89:1476\u0026ndash;85. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttp://dx.doi.org/10.2106/JBJS.F.00666\u003c/span\u003e\u003cspan address=\"10.2106/JBJS.F.00666\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"},{"header":"Tables","content":"\u003cp\u003eTable 1. Patients\u0026rsquo; characteristics\u0026nbsp;\u003c/p\u003e\n\u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\" width=\"595\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd width=\"20.672268907563026%\" valign=\"top\"\u003e\n \u003cp\u003eVariable\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"79.32773109243698%\" colspan=\"3\" valign=\"top\"\u003e\n \u003cp\u003eNo or average (range)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"20.63758389261745%\" valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"17.449664429530202%\" valign=\"top\"\u003e\n \u003cp\u003eTotal population (n=20)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"30.201342281879196%\" valign=\"top\"\u003e\n \u003cp\u003eGroup A (MB, n=10)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"31.711409395973153%\" valign=\"top\"\u003e\n \u003cp\u003eGroup B (PE CG, n=10)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"20.63758389261745%\" valign=\"top\"\u003e\n \u003cp\u003eMale/female\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"17.449664429530202%\" valign=\"top\"\u003e\n \u003cp\u003e8/12\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"30.201342281879196%\" valign=\"top\"\u003e\n \u003cp\u003e4/6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"31.711409395973153%\" valign=\"top\"\u003e\n \u003cp\u003e4/6\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"20.63758389261745%\" valign=\"top\"\u003e\n \u003cp\u003eAge at revision surgery (years)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"17.449664429530202%\" valign=\"top\"\u003e\n \u003cp\u003e66.6 (39-92)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"30.201342281879196%\" valign=\"top\"\u003e\n \u003cp\u003e70.3 (60-82)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"31.711409395973153%\" valign=\"top\"\u003e\n \u003cp\u003e63.3 (39-92)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"20.63758389261745%\" valign=\"top\"\u003e\n \u003cp\u003eSurgical site, right/left\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"17.449664429530202%\" valign=\"top\"\u003e\n \u003cp\u003e12/8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"30.201342281879196%\" valign=\"top\"\u003e\n \u003cp\u003e7/4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"31.711409395973153%\" valign=\"top\"\u003e\n \u003cp\u003e5/4\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"20.63758389261745%\" valign=\"top\"\u003e\n \u003cp\u003eDominant/non dominant\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"17.449664429530202%\" valign=\"top\"\u003e\n \u003cp\u003e12/8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"30.201342281879196%\" valign=\"top\"\u003e\n \u003cp\u003e7/4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"31.711409395973153%\" valign=\"top\"\u003e\n \u003cp\u003e5/4\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"20.63758389261745%\" valign=\"top\"\u003e\n \u003cp\u003eFollow-up (months)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"17.449664429530202%\" valign=\"top\"\u003e\n \u003cp\u003e60 (24-188)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"30.201342281879196%\" valign=\"top\"\u003e\n \u003cp\u003e50 (24-90)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"31.711409395973153%\" valign=\"top\"\u003e\n \u003cp\u003e60.1 (24-188)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"20.63758389261745%\" valign=\"top\"\u003e\n \u003cp\u003eTime from ATSA to RSA (months)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"17.449664429530202%\" valign=\"top\"\u003e\n \u003cp\u003e51.6 (0-155)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"30.201342281879196%\" valign=\"top\"\u003e\n \u003cp\u003e28.3 (0-93)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"31.711409395973153%\" valign=\"top\"\u003e\n \u003cp\u003e72.7 (0-155)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"20.63758389261745%\" valign=\"top\"\u003e\n \u003cp\u003eReasons for ATSA\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"17.449664429530202%\" valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"30.201342281879196%\" valign=\"top\"\u003e\n \u003cp\u003eGlenohumeral arthritis, n=9 PE glenoid loosening of previous TSA, n=1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"31.711409395973153%\" valign=\"top\"\u003e\n \u003cp\u003eGlenohumeral arthritis, n=7 Instability arthropathy, n=1\u003c/p\u003e\n \u003cp\u003eFailed resurfacing arthroplasty with glenoid dysplasia, n=1\u003c/p\u003e\n \u003cp\u003ePHF malunion, n=1\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"20.63758389261745%\" valign=\"top\"\u003e\n \u003cp\u003eReasons for ATSA revision\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"17.449664429530202%\" valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"30.201342281879196%\" valign=\"top\"\u003e\n \u003cp\u003eProthesis instability, n=6\u003c/p\u003e\n \u003cp\u003eRupture or non-functional PS RC, n=2\u003c/p\u003e\n \u003cp\u003eMechanical dissociation of the PE insert, n=1\u003c/p\u003e\n \u003cp\u003eSSC rupture, n=1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"31.711409395973153%\" valign=\"top\"\u003e\n \u003cp\u003eGlenoid loosening, n=6\u003c/p\u003e\n \u003cp\u003e\u0026nbsp; \u0026nbsp; \u0026nbsp;1/7 concomitant SSC rupture\u003c/p\u003e\n \u003cp\u003e\u0026nbsp; \u0026nbsp; \u0026nbsp;1/7 concomitant stiffness\u003c/p\u003e\n \u003cp\u003ePS RC rupture, n=2\u003c/p\u003e\n \u003cp\u003eDislocation, n=1 (bad quality SSC) Painful stiffness, n=1\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003eMB, metal-backed ; PE, polyethylene; CD, cemented-glenoid; ATSA, anatomic total shoulder arthroplasty; RSA, reverse shoulder arthroplasty; PHF, proximal humerus fracture; PS RC, posterosuperior rotator cuff; SSC, subscapularis\u003c/p\u003e\n\u003cp\u003eTable 2. Clinical and functional outcomes\u003c/p\u003e\n\u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\" align=\"\" width=\"472\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd width=\"29.872881355932204%\" valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"70.12711864406779%\" colspan=\"3\" valign=\"top\"\u003e\n \u003cp\u003en=20\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"29.936305732484076%\" valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"23.991507430997878%\" valign=\"top\"\u003e\n \u003cp\u003ePREOP\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"28.02547770700637%\" valign=\"top\"\u003e\n \u003cp\u003ePOSTOP\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"18.046709129511676%\" valign=\"top\"\u003e\n \u003cp\u003ep\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"29.936305732484076%\" valign=\"top\"\u003e\n \u003cp\u003eConstant-Murley score\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"23.991507430997878%\" valign=\"top\"\u003e\n \u003cp\u003e34\u003c/p\u003e\n \u003cp\u003e(16-58)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"28.02547770700637%\" valign=\"top\"\u003e\n \u003cp\u003e71.6\u003c/p\u003e\n \u003cp\u003e(49-89)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"18.046709129511676%\" valign=\"top\"\u003e\n \u003cp\u003e\u0026lt;0.001\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"29.872881355932204%\" valign=\"top\"\u003e\n \u003cp\u003eGain CMS\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"52.11864406779661%\" colspan=\"2\" valign=\"top\"\u003e\n \u003cp\u003e37\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"18.008474576271187%\" valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"29.936305732484076%\" valign=\"top\"\u003e\n \u003cp\u003eVAS score\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"23.991507430997878%\" valign=\"top\"\u003e\n \u003cp\u003e6.3 (4-9)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"28.02547770700637%\" valign=\"top\"\u003e\n \u003cp\u003e1 (0-7)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"18.046709129511676%\" valign=\"top\"\u003e\n \u003cp\u003e\u0026lt;0.001\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"29.936305732484076%\" valign=\"top\"\u003e\n \u003cp\u003eFE (deg)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"23.991507430997878%\" valign=\"top\"\u003e\n \u003cp\u003e101.6 (30-160)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"28.02547770700637%\" valign=\"top\"\u003e\n \u003cp\u003e150.5 (100-180)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"18.046709129511676%\" valign=\"top\"\u003e\n \u003cp\u003e\u0026lt;0.001\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"29.936305732484076%\" valign=\"top\"\u003e\n \u003cp\u003eER1 (deg)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"23.991507430997878%\" valign=\"top\"\u003e\n \u003cp\u003e19\u003c/p\u003e\n \u003cp\u003e(-30\u0026ndash; 60)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"28.02547770700637%\" valign=\"top\"\u003e\n \u003cp\u003e40.5\u003c/p\u003e\n \u003cp\u003e(20-70)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"18.046709129511676%\" valign=\"top\"\u003e\n \u003cp\u003e\u0026lt;0.001\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"29.936305732484076%\" valign=\"top\"\u003e\n \u003cp\u003eER2 (deg)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"23.991507430997878%\" valign=\"top\"\u003e\n \u003cp\u003e39\u003c/p\u003e\n \u003cp\u003e(0-90)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"28.02547770700637%\" valign=\"top\"\u003e\n \u003cp\u003e66.3\u003c/p\u003e\n \u003cp\u003e(30-90)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"18.046709129511676%\" valign=\"top\"\u003e\n \u003cp\u003e\u0026lt;0.001\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"29.936305732484076%\" valign=\"top\"\u003e\n \u003cp\u003eIR (points)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"23.991507430997878%\" valign=\"top\"\u003e\n \u003cp\u003e3.9 (2-6)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"28.02547770700637%\" valign=\"top\"\u003e\n \u003cp\u003e6.4 (2-10)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"18.046709129511676%\" valign=\"top\"\u003e\n \u003cp\u003e\u0026lt;0.001\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"29.936305732484076%\" valign=\"top\"\u003e\n \u003cp\u003eStrength (x/25)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"23.991507430997878%\" valign=\"top\"\u003e\n \u003cp\u003e4.9 (0-16)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"28.02547770700637%\" valign=\"top\"\u003e\n \u003cp\u003e8.2 (2-16)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"18.046709129511676%\" valign=\"top\"\u003e\n \u003cp\u003e0.018\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"29.936305732484076%\" valign=\"top\"\u003e\n \u003cp\u003eSST\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"23.991507430997878%\" valign=\"top\"\u003e\n \u003cp\u003e3.5 (1-6)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"28.02547770700637%\" valign=\"top\"\u003e\n \u003cp\u003e9.2 (8-12)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"18.046709129511676%\" valign=\"top\"\u003e\n \u003cp\u003e0.002\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"29.936305732484076%\" valign=\"top\"\u003e\n \u003cp\u003eSSV\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"23.991507430997878%\" valign=\"top\"\u003e\n \u003cp\u003e33.3 (20-50)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"28.02547770700637%\" valign=\"top\"\u003e\n \u003cp\u003e79.5 (50-100)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"18.046709129511676%\" valign=\"top\"\u003e\n \u003cp\u003e\u0026lt;0.001\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003eCMS, Constant Murley Score; VAS, visual analogue scale for pain; PREOP, preoperatively; POSTOP, postoperatively; FE, forward elevation; ER1, external rotation with arm at 0 degrees of abduction (arm at side of the body); ER2, external rotation with arm at 90 degrees of abduction; IR, internal rotation; SST; simple shoulder test; SSV, subjective shoulder value\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eTable 3. Outcomes depending on the primary TSA implant type\u0026nbsp;\u003c/p\u003e\n\u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\" align=\"\" width=\"572\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd width=\"16.404886561954626%\" valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"32.11169284467714%\" colspan=\"3\" valign=\"top\"\u003e\n \u003cp\u003eGroup A\u003c/p\u003e\n \u003cp\u003e(MB TSA, n=10)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"35.776614310645726%\" colspan=\"3\" valign=\"top\"\u003e\n \u003cp\u003eGroup B\u003c/p\u003e\n \u003cp\u003e(PE CG, n=10)\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"15.706806282722512%\" valign=\"top\"\u003e\n \u003cp\u003eBetween groups comparison\u003c/p\u003e\n \u003cp\u003epostoperative\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"16.404886561954626%\" valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"10.820244328097731%\" valign=\"top\"\u003e\n \u003cp\u003ePREOP\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"12.390924956369982%\" valign=\"top\"\u003e\n \u003cp\u003ePOSTOP\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"8.900523560209423%\" valign=\"top\"\u003e\n \u003cp\u003ep\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"11.8673647469459%\" valign=\"top\"\u003e\n \u003cp\u003ePREOP\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"14.31064572425829%\" valign=\"top\"\u003e\n \u003cp\u003ePOSTOP\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"9.598603839441536%\" valign=\"top\"\u003e\n \u003cp\u003ep\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"15.706806282722512%\" valign=\"top\"\u003e\n \u003cp\u003ep\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"16.404886561954626%\" valign=\"top\"\u003e\n \u003cp\u003eConstant-Murley score\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"10.820244328097731%\" valign=\"top\"\u003e\n \u003cp\u003e35.7\u003c/p\u003e\n \u003cp\u003e(16-58)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"12.390924956369982%\" valign=\"top\"\u003e\n \u003cp\u003e71.5\u003c/p\u003e\n \u003cp\u003e(55-85)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"8.900523560209423%\" valign=\"top\"\u003e\n \u003cp\u003e\u0026lt;0.001\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"11.8673647469459%\" valign=\"top\"\u003e\n \u003cp\u003e32.3\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e(21-45)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"14.31064572425829%\" valign=\"top\"\u003e\n \u003cp\u003e71.8\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e(49-89)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"9.598603839441536%\" valign=\"top\"\u003e\n \u003cp\u003e\u0026lt;0.001\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"15.706806282722512%\" valign=\"top\"\u003e\n \u003cp\u003e0.863\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"16.433566433566433%\" valign=\"top\"\u003e\n \u003cp\u003eGain CMS\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"23.076923076923077%\" colspan=\"2\" valign=\"top\"\u003e\n \u003cp\u003e35.8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"8.916083916083917%\" valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"26.223776223776223%\" colspan=\"2\" valign=\"top\"\u003e\n \u003cp\u003e38.2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"9.615384615384615%\" valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"15.734265734265735%\" valign=\"top\"\u003e\n \u003cp\u003e0.73\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"16.404886561954626%\" valign=\"top\"\u003e\n \u003cp\u003eVAS score\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"10.820244328097731%\" valign=\"top\"\u003e\n \u003cp\u003e5.9 (4-9)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"12.390924956369982%\" valign=\"top\"\u003e\n \u003cp\u003e0.1 (0-1)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"8.900523560209423%\" valign=\"top\"\u003e\n \u003cp\u003e\u0026lt;0.001\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"11.8673647469459%\" valign=\"top\"\u003e\n \u003cp\u003e6.6 (4-8)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"14.31064572425829%\" valign=\"top\"\u003e\n \u003cp\u003e1.9 (0-7)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"9.598603839441536%\" valign=\"top\"\u003e\n \u003cp\u003e\u0026lt;0.001\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"15.706806282722512%\" valign=\"top\"\u003e\n \u003cp\u003e0.004\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"16.404886561954626%\" valign=\"top\"\u003e\n \u003cp\u003eFE (deg)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"10.820244328097731%\" valign=\"top\"\u003e\n \u003cp\u003e94.4 (30-160)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"12.390924956369982%\" valign=\"top\"\u003e\n \u003cp\u003e154.4 (120-170)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"8.900523560209423%\" valign=\"top\"\u003e\n \u003cp\u003e0.004\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"11.8673647469459%\" valign=\"top\"\u003e\n \u003cp\u003e108\u003c/p\u003e\n \u003cp\u003e(80-140)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"14.31064572425829%\" valign=\"top\"\u003e\n \u003cp\u003e147\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e(100-180)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"9.598603839441536%\" valign=\"top\"\u003e\n \u003cp\u003e0.003\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"15.706806282722512%\" valign=\"top\"\u003e\n \u003cp\u003e0.661\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"16.404886561954626%\" valign=\"top\"\u003e\n \u003cp\u003eER1 (deg)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"10.820244328097731%\" valign=\"top\"\u003e\n \u003cp\u003e16\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e(-30\u0026ndash;40)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"12.390924956369982%\" valign=\"top\"\u003e\n \u003cp\u003e37.8\u003c/p\u003e\n \u003cp\u003e(20-70)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"8.900523560209423%\" valign=\"top\"\u003e\n \u003cp\u003e\u0026lt;0.001\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"11.8673647469459%\" valign=\"top\"\u003e\n \u003cp\u003e22\u003c/p\u003e\n \u003cp\u003e(-30 \u0026ndash; 60)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"14.31064572425829%\" valign=\"top\"\u003e\n \u003cp\u003e43\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e(30-70)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"9.598603839441536%\" valign=\"top\"\u003e\n \u003cp\u003e0.012\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"15.706806282722512%\" valign=\"top\"\u003e\n \u003cp\u003e0.447\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"16.404886561954626%\" valign=\"top\"\u003e\n \u003cp\u003eER2 (deg)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"10.820244328097731%\" valign=\"top\"\u003e\n \u003cp\u003e36\u003c/p\u003e\n \u003cp\u003e(0-70)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"12.390924956369982%\" valign=\"top\"\u003e\n \u003cp\u003e71.1\u003c/p\u003e\n \u003cp\u003e(40-90)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"8.900523560209423%\" valign=\"top\"\u003e\n \u003cp\u003e0.001\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"11.8673647469459%\" valign=\"top\"\u003e\n \u003cp\u003e42\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e(10-90)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"14.31064572425829%\" valign=\"top\"\u003e\n \u003cp\u003e62\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e(30-90)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"9.598603839441536%\" valign=\"top\"\u003e\n \u003cp\u003e0.06\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"15.706806282722512%\" valign=\"top\"\u003e\n \u003cp\u003e0.447\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"16.404886561954626%\" valign=\"top\"\u003e\n \u003cp\u003eIR (points)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"10.820244328097731%\" valign=\"top\"\u003e\n \u003cp\u003e4.2 (2-6)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"12.390924956369982%\" valign=\"top\"\u003e\n \u003cp\u003e6.4 (4-8)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"8.900523560209423%\" valign=\"top\"\u003e\n \u003cp\u003e0.028\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"11.8673647469459%\" valign=\"top\"\u003e\n \u003cp\u003e3.6 (2-6)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"14.31064572425829%\" valign=\"top\"\u003e\n \u003cp\u003e6.4 (2-10)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"9.598603839441536%\" valign=\"top\"\u003e\n \u003cp\u003e0.012\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"15.706806282722512%\" valign=\"top\"\u003e\n \u003cp\u003e0.931\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"16.404886561954626%\" valign=\"top\"\u003e\n \u003cp\u003eStrength (kg)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"10.820244328097731%\" valign=\"top\"\u003e\n \u003cp\u003e4.6 (0-6)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"12.390924956369982%\" valign=\"top\"\u003e\n \u003cp\u003e6.8 (2-12)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"8.900523560209423%\" valign=\"top\"\u003e\n \u003cp\u003e0.17\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"11.8673647469459%\" valign=\"top\"\u003e\n \u003cp\u003e5.2 (0-12)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"14.31064572425829%\" valign=\"top\"\u003e\n \u003cp\u003e9.7 (3-16)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"9.598603839441536%\" valign=\"top\"\u003e\n \u003cp\u003e0.07\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"15.706806282722512%\" valign=\"top\"\u003e\n \u003cp\u003e0.222\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"16.404886561954626%\" valign=\"top\"\u003e\n \u003cp\u003eSST\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"10.820244328097731%\" valign=\"top\"\u003e\n \u003cp\u003e3.5 (1-6)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"12.390924956369982%\" valign=\"top\"\u003e\n \u003cp\u003e9.2 (8-12)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"8.900523560209423%\" valign=\"top\"\u003e\n \u003cp\u003e0.002\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"11.8673647469459%\" valign=\"top\"\u003e\n \u003cp\u003e3.3 (1-5)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"14.31064572425829%\" valign=\"top\"\u003e\n \u003cp\u003e7.6 (2-10)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"9.598603839441536%\" valign=\"top\"\u003e\n \u003cp\u003e0.041\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"15.706806282722512%\" valign=\"top\"\u003e\n \u003cp\u003e0.432\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"16.404886561954626%\" valign=\"top\"\u003e\n \u003cp\u003eSSV\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"10.820244328097731%\" valign=\"top\"\u003e\n \u003cp\u003e34 (20-50)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"12.390924956369982%\" valign=\"top\"\u003e\n \u003cp\u003e82.2 (60-90)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"8.900523560209423%\" valign=\"top\"\u003e\n \u003cp\u003e0.000\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"11.8673647469459%\" valign=\"top\"\u003e\n \u003cp\u003e32.5 (20-50)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"14.31064572425829%\" valign=\"top\"\u003e\n \u003cp\u003e77 (50-100)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"9.598603839441536%\" valign=\"top\"\u003e\n \u003cp\u003e0.000\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"15.706806282722512%\" valign=\"top\"\u003e\n \u003cp\u003e0.315\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"16.404886561954626%\" valign=\"top\"\u003e\n \u003cp\u003eSatisfaction\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"10.820244328097731%\" valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"12.390924956369982%\" valign=\"top\"\u003e\n \u003cp\u003e8 VS, 2S\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"8.900523560209423%\" valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"11.8673647469459%\" valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"14.31064572425829%\" valign=\"top\"\u003e\n \u003cp\u003e7\u0026nbsp;VS, 2S, 1 fair\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"9.598603839441536%\" valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"15.706806282722512%\" valign=\"top\"\u003e\n \u003cp\u003e0.587\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"16.404886561954626%\" valign=\"top\"\u003e\n \u003cp\u003eComplications\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"10.820244328097731%\" valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"12.390924956369982%\" valign=\"top\"\u003e\n \u003cp\u003enone\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"8.900523560209423%\" valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"11.8673647469459%\" valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"14.31064572425829%\" valign=\"top\"\u003e\n \u003cp\u003e1 reoperation for instability\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"9.598603839441536%\" valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"15.706806282722512%\" valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003eMB TSA, metal-backed total shoulder arthroplasty; PE CG, Polyethylene cemented glenoid implant; CMS, Constant Murley Score; VAS, visual analogue scale for pain; PREOP, preoperatively; POSTOP, postoperatively; FE, forward elevation; ER1, external rotation with arm at 0 degrees of abduction (arm at side of the body); ER2, external rotation with arm at 90 degrees of abduction; IR, internal rotation; SST; simple shoulder test; SSV, subjective shoulder value; VS, very satisfied; S, satisfied.\u003c/p\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"Anatomic total shoulder arthroplasty, reverse shoulder arthroplasty, revision, platform shoulder system, convertible system, metal-backed glenoid implant","lastPublishedDoi":"10.21203/rs.3.rs-4296824/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-4296824/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003e\u003cstrong\u003eBackground\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe objective of this study is to report the outcomes after revision of anatomical total shoulder arthroplasty (ATSA) to reverse shoulder arthroplasty (RSA) and to compare between groups depending on the primary ATSA glenoid implant type, cemented polyethylene (PE) versus a convertible metal-backed (MB). The hypothesis was that the outcomes would differ between patients treated with ATSA with PE and MB implants in favor of the platform system.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eMethods\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eGroup A included ten cases of convertible MB glenoid that were revised due to instability (six cases), posterosuperior rotator cuff tear (RCT) (two cases), subscapularis rupture (one case) and polyethylene dissociation (one case); Group B included ten cases of cemented PE that were revised due to glenoid loosening (six cases), RCT (two cases), dislocation (one case), and painful stiffness (one case). Active motion, Constant score, subjective shoulder value, Simple Shoulder Test and pain (VAS) were evaluated at minimum follow-up of two years. Student’s t test and Mann-Whitney tests were used for statistical analysis. Level of significance α=0.05.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eResults\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eFor the entire study cohort, postoperative results were improved compared to the preoperative state (p\u0026lt;0.05) at mean follow-up 60 months (24-188). Group A demonstrated improved postoperative pain levels compared to Group B (VAS 0.1 vs 1.9; p=0.004). No other differences were detected between the two groups (p\u0026gt;0.05). One complication occurred in Group B where one patient was re-operated for RSA instability with a good final functional outcome.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConclusions\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eATSA to RSA conversion resulted in improved functional outcomes. Post RSA motion and functional outcomes did not differ between the two groups with exception of reduced pain levels for patients treated with a convertible MB ATSA system.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eLevel of evidence\u003c/strong\u003e: III; retrospective comparative study; treatment study\u003c/p\u003e","manuscriptTitle":"Outcomes after revision of anatomic total shoulder arthroplasty to reverse shoulder arthroplasty and comparison between cemented or metal-backed glenoid in platform systems.","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2024-08-09 16:19:41","doi":"10.21203/rs.3.rs-4296824/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"b3a41ca8-2ff5-4ea9-8cbd-366bf7dd22a6","owner":[],"postedDate":"August 9th, 2024","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2025-02-10T14:08:55+00:00","versionOfRecord":[],"versionCreatedAt":"2024-08-09 16:19:41","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-4296824","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-4296824","identity":"rs-4296824","version":["v1"]},"buildId":"qtupq5eGEP_6zYnWcrvyt","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}