Aims. Reverse shoulder arthroplasty (RSA) has become the most common type of shoulder arthroplasty used in the UK, and a better understanding of the outcomes after revision of a failed RSA is needed. The aim of this study was to review the current evidence systematically to determine patient-reported outcome measures and the rates of re-revision and complications for patients undergoing revision of a RSA. Methods. MEDLINE, Embase, CENTRAL, and the Cochrane Database of Systematic Reviews were searched. Studies involving adult patients who underwent revision of a primary RSA for any indication were included. Those who underwent a RSA for failure of a total shoulder arthroplasty or hemiarthroplasty were excluded. Pre- and postoperative shoulder scores were evaluated in a random effects meta-analysis to determine the mean difference. The rates of re-revision and complications were also calculated. Results. The initial search elicited 3,166 results and, following removal of duplicates and screening, 13 studies with a total of 1,042 RSAs were identified. An increase in shoulder scores pre- to postoperatively was reported in all the studies. Following revision of a RSA to a further RSA, there was a significant increase in the American Shoulder and Elbow Surgeons Score (mean difference 20.78 (95% CI 8.16 to 33.40); p = 0.001). A re-revision rate at final follow-up ranging from 9% to 32%, a one-year re-revision rate of 14%, and a five-year re-revision rate of 23% were reported. The complication rate in all the studies was between 18.5% and 36%, with a total incidence of 29%. Conclusion. This is the largest systematic review of the outcomes following revision of a RSA. We found an improvement in functional outcomes after revision surgery, but the rates of re-revision and complications are high and warrant consideration when planning a revision procedure. Cite this article: Bone Joint J 2024;106-B(11):1293–1300

Aims. Optimal glenoid positioning in reverse shoulder arthroplasty (RSA) is crucial to provide impingement-free range of motion (ROM). Lateralization and inclination correction are not yet systematically used. Using planning software, we simulated the most used glenoid implant positions. The primary goal was to determine the configuration that delivers the best theoretical impingement-free ROM. Methods. With the use of a 3D planning software (Blueprint) for RSA, 41 shoulders in 41 consecutive patients (17 males and 24 females; means age 73 years (SD 7)) undergoing RSA were planned. For the same anteroposterior positioning and retroversion of the glenoid implant, four different glenoid baseplate configurations were used on each shoulder to compare ROM: 1) no correction of the RSA angle and no lateralization (C-L-); 2) correction of the RSA angle with medialization by inferior reaming (C+M+); 3) correction of the RSA angle without lateralization by superior compensation (C+L-); and 4) correction of the RSA angle and additional lateralization (C+L+). The same humeral inlay implant and positioning were used on the humeral side for the four different glenoid configurations with a 3 mm symmetric 135° inclined polyethylene liner. Results. The configuration with lateralization and correction of the RSA angle (C+L+) led to better ROM in flexion, extension, adduction, and external rotation (p ≤ 0.001). Only internal rotation was not significantly different between groups (p = 0.388). The configuration where correction of the inclination was done by medialization (C+M+) led to the worst ROM in adduction, extension, abduction, flexion, and external rotation of the shoulder. Conclusion. Our software study shows that, when using a 135° inlay reversed humeral implant, correcting glenoid inclination (RSA angle 0°) and lateralizing the glenoid component by using an angled bony or metallic augment of 8 to 10 mm provides optimal impingement-free ROM. Cite this article: Bone Jt Open 2024;5(10):851–857

Aims. This study aimed to assess the impact of using the metal-augmented glenoid baseplate (AGB) on improving clinical and radiological outcomes, as well as reducing complications, in patients with superior glenoid wear undergoing reverse shoulder arthroplasty (RSA). Methods. From January 2016 to June 2021, out of 235 patients who underwent primary RSA, 24 received a superior-AGB after off-axis reaming (Group A). Subsequently, we conducted propensity score matching in a 1:3 ratio, considering sex, age, follow-up duration, and glenoid wear (superior-inclination and retroversion), and selected 72 well-balanced matched patients who received a standard glenoid baseplate (STB) after eccentric reaming (Group B). Superior-inclination, retroversion, and lateral humeral offset (LHO) were measured to assess preoperative glenoid wear and postoperative correction, as well as to identify any complications. Clinical outcomes were measured at each outpatient visit before and after surgery. Results. There were no significant differences in demographic data and preoperative characteristics between the two groups. Both groups showed significant improvements in patient-reported outcome measures (visual analogue scale for pain, visual analogue scale for function, American Shoulder and Elbow Surgeons, Constant, and Simple Shoulder Test scores) from preoperative to final assessment (p < 0.001). However, AGB showed no additional benefit. Notably, within range of motion, Group B showed significant postoperative decrease in both external rotation and internal rotation, unlike Group A (p = 0.028 and 0.003, respectively). Both groups demonstrated a significant correction of superior-inclination after surgery, while patients in Group B exhibited a significant decrease in LHO postoperatively (p = 0.001). Regarding complications, Group A experienced more acromial stress fractures (3 cases; 12.5%), whereas Group B had a higher occurrence of scapular notching (24 cases; 33.3%) (p = 0.008). Conclusion. Both eccentric reaming with STB and off-axis reaming with AGB are effective methods for addressing superior glenoid wear in RSA, leading to improved clinical outcomes. However, it is important to be aware of the potential risks associated with eccentric reaming, which include excessive bone loss leading to reduced rotation and scapular notching. Cite this article: Bone Joint J 2024;106-B(3):268–276

Aims. The aim of this study was to compare the clinical and radiological outcomes of reverse shoulder arthroplasty (RSA) using small and standard baseplates in Asian patients, and to investigate the impact of a mismatch in the sizes of the glenoid and the baseplate on the outcomes. Methods. This was retrospective analysis of 50 and 33 RSAs using a standard (33.8 mm, ST group) and a small (29.5 mm, SM group) baseplate of the Equinoxe reverse shoulder system, which were undertaken between January 2017 and March 2021. Radiological evaluations included the size of the glenoid, the β-angle, the inclination of the glenoid component, inferior overhang, scapular notching, the location of the central cage in the baseplate within the vault and the mismatch in size between the glenoid and baseplate. Clinical evaluations included the range of motion (ROM) and functional scores. In subgroup analysis, comparisons were performed between those in whom the vault of the glenoid was perforated (VP group) and those in whom it was not perforated (VNP group). Results. Perforation of the vault of the glenoid (p = 0.018) and size mismatch in height (p < 0.001) and width (p = 0.013) were significantly more frequent in the ST group than in the SM group. There was no significant difference in the clinical scores and ROM in the two groups, two years postoperatively (all p > 0.05). In subgroup analysis, the VP group had significantly less inferior overhang (p = 0.009), more scapular notching (p = 0.018), and more size mismatch in height (p < 0.001) and width (p = 0.025) than the VNP group. Conclusion. In Asian patients with a small glenoid, using a 29.5 mm small baseplate at the time of RSA was more effective in reducing size mismatch between the glenoid and the baseplate, decreasing the incidence of perforation of the glenoid vault, and achieving optimal positioning of the baseplate compared with the use of a 33.8 mm standard baseplate. However, longer follow-up is required to assess the impact of these findings on the clinical outcomes. Cite this article: Bone Joint J 2023;105-B(11):1189–1195

Aims. Favourable short-term outcomes have been reported following latissimus dorsi tendon transfer for patients with an irreparable subscapularis (SSC) tendon tear. The aim of this study was to investigate the long-term outcomes of this transfer in these patients. Methods. This was a retrospective study involving 30 patients with an irreparable SSC tear and those with a SSC tear combined with a reparable supraspinatus tear, who underwent a latissimus dorsi tendon transfer. Clinical scores and active range of motion (aROM), SSC-specific physical examination and the rate of return to work were assessed. Radiological assessment included recording the acromiohumeral distance (AHD), the Hamada grade of cuff tear arthropathy and the integrity of the transferred tendon. Statistical analysis compared preoperative, short-term (two years), and final follow-up at a mean of 8.7 years (7 to 10). Results. There were significant improvements in clinical scores, in the range and strength of internal rotation and aROM compared with the preoperative values in the 26 patients (87%) who were available for long-term follow-up. These improvements were maintained between short- and long-term follow-ups. Although there was a decreased mean AHD of 7.3 mm (SD 1.5) and an increased mean Hamada grade of 1.7 (SD 0.5) at final follow-up, the rate of progression of cuff tear arthropathy remained low-grade. Comparison between the isolated SSC and combined SSC and reparable supraspinatus tear groups showed no significant differences. At final follow-up, one patient (3.8%) had undergone revision surgery to a reverse shoulder arthroplasty (RSA). No neurological complications were associated with the procedure. Conclusion. Latissimus dorsi transfer for an irreparable SSC tendon tear resulted in a significant clinical improvement, particularly in pain, range and strength of internal rotation and aROM, which were maintained over a mean of 8.7 years following surgery. Given that this was a long-term outcome study, there was a low-grade progression in the rate of cuff tear arthropathy. Thus, the long-term clinical efficacy of latissimus dorsi tendon transfer in patients with irreparable SSC was confirmed as a joint-preserving procedure for these patients, suggesting it as an effective alternative to RSA in young, active patients without degenerative changes of the glenohumeral joint. Cite this article: Bone Joint J 2024;106-B(9):957–963

Aims

Stemless humeral implants have been developed to overcome stem-related complications in total shoulder arthroplasty (TSA). However, stemless implant designs may hypothetically result in less stable initial fixation, potentially affecting long-term survival. The aim of this study is to investigate early fixation and migration patterns of the stemless humeral component of the Simpliciti Shoulder System and to evaluate clinical outcomes.

We determined the short-term clinical outcome and migration within the bone of the humeral cementless component of the Instrumented Bone Preserving (IBP) total elbow replacement in a series of 16 patients. There were four men and 12 women with a mean age at operation of 63 years (40 to 81). Migration was calculated using radiostereometric analysis. There were no intra-operative complications and no revisions. At two-year follow-up, all patients showed a significant reduction in pain and functional improvement of the elbow (both p < 0.001). Although ten components (63%) showed movement or micromovement during the first six weeks, 14 (88%) were stable at one year post-operatively. Translation was primarily found in the proximal direction (median 0.3 mm (interquartile range (IQR) -0.09 to 0.8); the major rotational movement was an anterior tilt (median 0.7° (IQR 0.4° to 1.6°)). One malaligned component continued to migrate during the second year, and one component could not be followed beyond three months because migration had caused the markers to break off the prosthesis.

This study shows promising early results for the cementless humeral component of the IBP total elbow replacement. All patients had a good clinical outcome, and most components stabilised within six months of the operation.

Cite this article: Bone Joint J 2014;96-B:229–36.

Aims. Reverse total shoulder arthroplasty (rTSA) can be used in complex cases when the glenoid requires reconstruction. In this study, a baseplate with composite bone autograft and a central trabecular titanium peg was implanted, and its migration was assessed for two years postoperatively using radiostereometric analysis (RSA). Methods. A total of 14 patients who underwent a rTSA with an autograft consented to participate. Of these, 11 had a primary rTSA using humeral head autograft and three had a revision rTSA with autograft harvested from the iliac crest. The mean age of the patients was 66 years (39 to 81). Tantalum beads were implanted in the scapula around the glenoid. RSA imaging (stereographic radiographs) was undertaken immediately postoperatively and at three, six, 12, and 24 months. Analysis was completed using model-based RSA software. Outcomes were collected preoperatively and at two years postoperatively, including the Oxford Shoulder Score, the American Shoulder and Elbow Score, and a visual analogue score for pain. A Constant score was also obtained for the assessment of strength and range of motion. Results. RSA analysis showed a small increase in all translation and rotational values up to six months postoperatively, consistent with settling of the implant. The mean values plateaued by 12 months, with no evidence of further migration. In four patients, there was significant variation outside the mean, which corresponded to postoperative complications. There was a significant improvement in the clinical and patient-reported outcomes from the preoperative values to those at two years postoperatively (p < 0.001). Conclusion. These findings show, using RSA, that a glenoid baseplate composite of a trabecular titanium peg with autograft stabilizes within the glenoid about 12 months after surgery, and reinforce findings from a previous study of this implant/graft with CT scans at two years postoperatively, indicating that this type of structural composite results in sound early fixation. Cite this article: Bone Joint J 2023;105-B(8):912–919

Aims. This study aimed to quantify the shoulder kinematics during an apprehension-relocation test in patients with anterior shoulder instability (ASI) and glenoid bone loss using the radiostereometric analysis (RSA) method. Kinematics were compared with the patient’s contralateral healthy shoulder. Methods. A total of 20 patients with ASI and > 10% glenoid bone loss and a healthy contralateral shoulder were included. RSA imaging of the patient’s shoulders was performed during a repeated apprehension-relocation test. Bone volume models were generated from CT scans, marked with anatomical coordinate systems, and aligned with the digitally reconstructed bone projections on the RSA images. The glenohumeral joint (GHJ) kinematics were evaluated in the anteroposterior and superoinferior direction of: the humeral head centre location relative to the glenoid centre; and the humeral head contact point location on the glenoid. Results. During the apprehension test, the centre of the humeral head was 1.0 mm (95% CI 0.0 to 2.0) more inferior on the glenoid for the ASI shoulder compared with the healthy shoulder. Furthermore, the contact point of the ASI shoulder was 1.4 mm (95% CI 0.3 to 2.5) more anterior and 2.0 mm (95% CI 0.8 to 3.1) more inferior on the glenoid compared with the healthy shoulder. The contact point of the ASI shoulder was 1.2 mm (95% CI 0.2 to 2.6) more anterior during the apprehension test compared to the relocation test. Conclusion. The humeral head centre was located more inferior, and the GHJ contact point was located both more anterior and inferior during the apprehension test for the ASI shoulders than the healthy shoulders. Furthermore, the contact point displacement between the apprehension and relocation test revealed increased joint laxity for the ASI shoulder than the healthy shoulders. These results contribute to existing knowledge that ASI shoulders with glenoid bone loss may also suffer from inferior shoulder instability. Cite this article: Bone Joint J 2024;106-B(10):1133–1140

Aims. Existing literature indicates that inferiorly inclined glenoid baseplates following reverse total shoulder arthroplasty (RSA) produce better outcomes compared to superiorly inclined baseplates. We aim to compare clinical outcomes for RSAs with superiorly and neutrally/inferiorly inclined lateralized glenospheres. Methods. We retrospectively reviewed 154 consecutive patients undergoing RSA between July 2015 and July 2017 by one single-fellowship trained surgeon (AJ). Two raters (KAM and MVS) independently measured glenoid inclination in preoperative and minimum two year follow-up radiographs (anteroposterior/Grashey) using the RSA angle. Inclination was then compared to patient-reported outcomes, range of motion (ROM), and independently assessed degree of scapular notching and staging of heterotopic ossification at two year follow-up. Results. Median postoperative inclination for each group was found to be -3.6° (interquartile range (IQR) -2.1 to -6.9) and 6.0° (3.2° to 10.1°) for the neutrally/inferiorly and superiorly inclined cohorts, respectively. Preoperative inclination was highly associated with postoperative inclination (p = 0.004). When comparing superiorly and neutrally/inferiorly inclined glenospheres, there were no differences in heterotopic ossification (p = 0.606), scapular notching (p = 0.367), American Shoulder and Elbow Surgeons score (p = 0.419), Single Assessment Numeric Evaluation (p = 0.417), Visual Analogue Scale (VAS) pain score (p = 0.290), forward elevation (p = 0.161), external rotation (p = 0.537), or internal rotation (p = 0.656). Conclusion. Compared to neutral and inferior inclination, up to 6° ± 3° of superior glenoid baseplate inclination on a lateralized RSA design produces no differences in postoperative ROM or patient-reported outcomes, and produces similar levels of scapular notching and heterotopic ossification. Additionally, the degree of preoperative inclination represents an important factor in surgical decision-making as it is strongly associated with postoperative inclination. It is important to note that the findings of this study are only reflective of lateralized RSA prostheses. Cite this article: Bone Joint J 2021;103-B(2):360–365

Aims. Reverse shoulder arthroplasty (RSA) reliably improves shoulder pain and function for a variety of indications. However, the safety and efficacy of RSA in elderly patients is largely unknown. The purpose of this study was to report the mortality, morbidity, complications, reoperations, and outcomes of primary RSA in patients aged > 80 years. Patients and Methods. Between 2004 and 2013, 242 consecutive primary RSAs were performed in patients aged > 80 years (mean 83.3 years (. sd. 3.1)). Of these, 53 were lost to follow-up before two years and ten had died within two years of surgery, leaving 179 for analysis of survivorship, pain, motion, and strength at a minimum of two years or until revision surgery. All 242 patients were considered for the analysis of 90-day, one-year, and overall mortality, medical complications (90-day and overall), surgical complications, and reoperations. The indications for surgery included rotator cuff arthropathy, osteoarthritis, fracture, the sequela of trauma, avascular necrosis, and rheumatoid arthritis. A retrospective review of the medical records was performed to collect all variables. Survivorship free of revision surgery was calculated at two and five years. Results. One patient (0.4%) died within the first 90 days. A total of 45 patients (19%) were known to have died at the time of the final follow-up, with a median time to death of 67.7 months (interquartile range 40.4 to 94.7) postoperatively. Medical complications occurred in six patients (3%) and surgical complications occurred in 21/179 patients (12%). Survivorship free from revision was 98.9% at two years and 98.3% at five years; survivorship free from loosening was 99.5% at final follow-up. The presence of peripheral vascular disease correlated with a higher complication rate. Conclusion. Primary RSA was safe and effective in patients aged > 80 years, with a relatively low rate of medical and surgical complications. Thus, age alone should not be a contraindication to primary RSA in patients aged > 80 years. However, a careful evaluation of comorbidities is required in this age group when considering primary RSA. Cite this article: Bone Joint J 2019;101-B:1520–1525

Aims. The purpose of this study was to determine whether there were long-term differences in outcomes of reverse shoulder arthroplasty (RSA) undertaken for acute proximal humeral fracture versus rotator cuff deficiency with a minimum follow-up of five years. Methods. This was a prospective cohort study comparing 67 patients with acute complex proximal humeral fracture and 64 patients with irreparable rotator cuff deficiency who underwent primary RSA. In the fracture group, there were 52 (77.6%) females and 15 (22.4%) males, with a mean age of 73.5 years (51 to 85), while in the arthropathy group, there were 43 (67.1%) females and 21 (32.9%) males, with a mean age of 70.6 years (50 to 84). Patients were assessed by the Constant score, University of California Los Angeles shoulder score (UCLA), short version of the Disability of the Arm Shoulder and Hand score (QuickDASH), and visual analogue scales (VAS) for pain and satisfaction. Radiological evaluation was also performed. Results. Mean follow-up was 8.4 years (5 to 11). There were no significant differences in mean absolute (p = 0.125) or adjusted (p = 0.569) Constant, UCLA (p = 0.088), QuickDASH (p = 0.135), VAS-pain (p = 0.062), or range of movement at the final follow-up. However, patient satisfaction was significantly lower in the fracture group (p = 0.002). The complication rate was 1.5% (one patient) versus 9.3% (six patients), and the revision rate was 1.5% (one patient) versus 7.8% (five patients) in the fracture and arthropathy groups, respectively. The ten-year arthroplasty survival was not significantly different (p = 0.221). Conclusion. RSA may be used not only for patients with irreparable rotator cuff deficiencies, but also for those with acute complex proximal humeral fractures. We found that RSA provided similar functional outcomes and a low revision rate for both indications at long-term. However, satisfaction is lower in patients with an acute fracture. Cite this article: Bone Joint J 2020;102-B(11):1555–1559

Aims. The number of rotator cuff repairs that are undertaken is increasing. Reverse shoulder arthroplasty (RSA) is the procedure of choice for patients with rotator cuff arthropathy. We sought to determine whether patients who underwent rotator cuff repair and subsequent RSA had different outcomes compared with a matched control group who underwent RSA without a previous rotator cuff repair. Patients and Methods. All patients with a history of rotator cuff repair who underwent RSA between 2000 and 2015 with a minimum follow-up of two years were eligible for inclusion as the study group. Outcomes, including the American Shoulder and Elbow Surgeons (ASES) scores, were compared with a matched control group of patients who underwent RSA without having previously undergone rotator cuff repair. Results. The study group included 45 patients. Their mean age was 69 years (. sd. 8.6) and 27 patients (60%) were women. The mean ASES score improved from 43.1 to 76.6 two years postoperatively, and to 66.9 five years postoperatively. There was no significant difference between the outcomes at two years in the two groups (all p ≥ 0.05), although there was significantly more improvement in ASES scores in the control group (44.5 vs 33.4; p = 0.01). However, there was no significant difference between ASES scores at two and five years when baseline ASES scores were matched in the two groups (p = 0.42 at two years; p = 0.35 at five years). Conclusion. Significant improvements in ASES scores were seen following RSA in patients who had previously undergone rotator cuff repair. They had higher baseline ASES scores than those who had not previously undergone this surgery. However, there was no significant difference in outcomes between the two groups, two years postoperatively. Previous rotator cuff repair does not appear to affect the early outcome after RSA adversely

Aims. Patients with a failed reverse shoulder arthroplasty (RSA) have limited salvage options. The aim of this study was to determine the outcome of revision RSA when used as a salvage procedure for a failed primary RSA. Patients and Methods. We reviewed all revision RSAs performed for a failed primary RSA between 2006 and 2012, excluding patients with a follow-up of less than two years. A total of 27 revision RSAs were included in the study. The mean age of the patients at the time of revision was 70 years (58 to 82). Of the 27 patients, 14 (52% were female). The mean follow-up was 4.4 years (2 to 10). Results. Six patients (22%) developed complications requiring further revision surgery, at a mean of 1.7 years (0.1 to 5.3) postoperatively. The indication for further revision was dislocation in two, glenoid loosening in one, fracture of the humeral component in one, disassociation of the glenosphere in one, and infection in one. The five-year survival free of further revision was 85%. Five additional RSAs developed complications that did not need surgery, including dislocation in three and periprosthetic fracture in two. Overall, patients who did not require further revision had excellent pain relief, and significant improvements in elevation and external rotation of the shoulder (p < 0.01). The mean postoperative American Shoulder and Elbow Surgeons (ASES), and simple shoulder test (SST) scores were 66 and 7, respectively. Radiological results were available in 26 patients (96.3%) at a mean of 4.3 years (1.5 to 9.5). At the most recent follow-up, six patients (23%) had glenoid lucency, which were classified as grade III or higher in three (12%). Smokers had a significantly increased risk of glenoid lucency (p < 0.01). Conclusion. Revision RSA, when used to salvage a failed primary RSA, can be a successful procedure. At intermediate follow-up, survival rates are reasonable, but dislocation and glenoid lucency remain a concern, particularly in smokers. Cite this article: Bone Joint J 2018;100-B:1493–98

Aims. The purpose of this study was to evaluate the cost of reverse shoulder arthroplasty (RSA) for patients with a proximal humerus fracture, using time-driven activity based costing (TDABC), and to compare treatment costs with reimbursement under the Healthcare Resource Groups (HRGs). Methods. TDABC analysis based on the principles outlined by Kaplan and a clinical pathway that has previously been validated for this institution was used. Staffing cost, consumables, implants, and overheads were updated to reflect 2019/2020 costs. This was compared with the HRG reimbursements. Results. The mean cost of a RSA is £7,007.46 (£6,130.67 to £8,824.67). Implants and staffing costs were the primary cost drivers, with implants (£2,824.80) making up 40% of the costs. Staffing costs made up £1,367.78 (19%) of overall costs. The total tariff, accounting for market force factors and high comorbidities, reimburses £4,629. If maximum cost and minimum reimbursement is applied the losses to the trust are £4,828.67. Conclusion. RSA may be an effective and appropriate surgical option in the treatment of proximal humerus fractures; however, a cost analysis at our centre has demonstrated the financial burden of this surgery. Given its increasing use in trauma, there is a need to work towards generating an HRG that adequately reimburses providers. Cite this article: Bone Jt Open 2020;1-12:731–736

Aims. The aim of this study was to report the outcomes of different treatment options for glenoid loosening following reverse shoulder arthroplasty (RSA) at a minimum follow-up of two years. Patients and Methods. We retrospectively studied the records of 79 patients (19 men, 60 women; 84 shoulders) aged 70.4 years (21 to 87) treated for aseptic loosening of the glenosphere following RSA. Clinical evaluation included pre- and post-treatment active anterior elevation (AAE), external rotation, and Constant score. Results. From the original cohort, 29 shoulders (35%) were treated conservatively, 27 shoulders (32%) were revised by revision of the glenosphere, and 28 shoulders (33%) were converted to hemiarthroplasty. At last follow-up, conservative treatment and glenoid revision significantly improved AAE, total Constant score, and pain, while hemiarthroplasty did not improve range of movement or clinical scores. Multivariable analysis confirmed that conservative treatment and glenoid revision achieved similar improvements in pain (glenoid revision vs conservative, beta 0.44; p = 0.834) but that outcomes were significantly worse following hemiarthroplasty (beta -5.00; p = 0.029). Conclusion. When possible, glenoid loosening after RSA should first be treated conservatively, then by glenosphere revision if necessary, and last by salvage hemiarthroplasty. Cite this article: Bone Joint J 2019;101-B:461–469

Objectives. To date, no study has considered the impact of acromial morphology on shoulder range of movement (ROM). The purpose of our study was to evaluate the effects of lateralization of the centre of rotation (COR) and neck-shaft angle (NSA) on shoulder ROM after reverse shoulder arthroplasty (RSA) in patients with different scapular morphologies. Methods. 3D computer models were constructed from CT scans of 12 patients with a critical shoulder angle (CSA) of 25°, 30°, 35°, and 40°. For each model, shoulder ROM was evaluated at a NSA of 135° and 145°, and lateralization of 0 mm, 5 mm, and 10 mm for seven standardized movements: glenohumeral abduction, adduction, forward flexion, extension, internal rotation with the arm at 90° of abduction, as well as external rotation with the arm at 10° and 90° of abduction. Results. CSA did not seem to influence ROM in any of the models, but greater lateralization achieved greater ROM for all movements in all configurations. Internal and external rotation at 90° of abduction were impossible in most configurations, except in models with a CSA of 25°. Conclusion. Postoperative ROM following RSA depends on multiple patient and surgical factors. This study, based on computer simulation, suggests that CSA has no influence on ROM after RSA, while lateralization increases ROM in all configurations. Furthermore, increasing subacromial space is important to grant sufficient rotation at 90° of abduction. In summary, increased lateralization of the COR and increased subacromial space improve ROM in all CSA configurations. Cite this article: A. Lädermann, E. Tay, P. Collin, S. Piotton, C-H Chiu, A. Michelet, C. Charbonnier. Effect of critical shoulder angle, glenoid lateralization, and humeral inclination on range of movement in reverse shoulder arthroplasty. Bone Joint Res 2019;8:378–386. DOI: 10.1302/2046-3758.88.BJR-2018-0293.R1

Aims. Shoulder arthroplasty using short humeral components is becoming increasingly popular. Some such components have been associated with relatively high rates of adverse radiological findings. The aim of this retrospective review was to evaluate the radiological humeral bone changes and mechanical failure rates with implantation of a short cementless humeral component in anatomical (TSA) and reverse shoulder arthroplasty (RSA). Patients and Methods. A total of 100 shoulder arthroplasties (35 TSA and 65 RSA) were evaluated at a mean of 3.8 years (3 to 8.3). The mean age at the time of surgery was 68 years (31 to 90). The mean body mass index was 32.7 kg/m. 2. (17.3 to 66.4). Results. Greater tuberosity stress shielding was noted in 14 shoulders (two TSA and 12 RSA) and was graded as mild in nine, moderate in two, and severe in three. Medial calcar resorption was noted in 23 shoulders (seven TSA and 16 RSA), and was graded as mild in 21 and moderate in two. No humeral components were revised for loosening or considered to be loose radiologically. Nine shoulders underwent reoperation for infection (n = 3), fracture of the humeral tray (n = 2), aseptic glenoid loosening (n = 1), and instability (n = 3). No periprosthetic fractures occurred. Conclusion. Implantation of this particular short cementless humeral component at the time of TSA or RSA was associated with a low rate of adverse radiological findings on the humeral side at mid-term follow-up. Our data do not raise any concerns regarding the use of a short stem in TSA or RSA. Cite this article: Bone Joint J 2019;101-B:610–614

Aims. Scapular notching is a frequently observed radiographic phenomenon in reverse shoulder arthroplasty (RSA), signifying impingement of components. The purposes of this study were to evaluate the effect of glenoid component size and glenosphere type on impingement-free range of movement (ROM) for extension and internal and external rotation in a virtual RSA model, and to determine the optimal configuration to reduce the incidence of friction-type scapular notching. Materials and Methods. Preoperative CT scans obtained in 21 patients (three male, 18 female) with primary osteoarthritis were analyzed using modelling software. Two concurrent factors were tested for impingement-free ROM and translation of the centre of rotation: glenosphere diameter (36 mm vs 39 mm) and type (centred, 2 mm inferior eccentric offset, 10° inferior tilt). Results. Glenosphere size was most predictive of increased extension and external rotation, whereas lateralization of the centre of rotation was the most predictive factor for internal rotation. A larger diameter of glenosphere combined with a 10° tilted configuration demonstrated superior values for extension and external rotation, whereas the eccentric component improved internal rotation by a mean 8.9° (standard deviation 2.7°) compared with a standard concentric glenosphere. Conclusion. Glenosphere configuration can be modified to increase range of movement in RSA. Friction-type scapular notching was most effectively reduced by use of a large-diameter glenosphere with 10° inferior tilt. Cite this article: Bone Joint J 2018;100-B:1182–6

Aims. To investigate the impact of the Charlson and Elixhauser comorbidity indices on patient-reported outcomes measures (PROMs) following shoulder arthroplasty. Methods. Patients undergoing total shoulder arthroplasty (TSA), reverse shoulder arthroplasty (RSA), or hemiarthroplasty (HA) from 2016 to 2018 were identified, along with the Charlson and Elixhauser comorbidities listed as their secondary diagnoses in the electronic medical records. Patients were matched to our institution’s registry to obtain their PROMs, including shoulder-specific (American Shoulder and Elbow Society (ASES) and Shoulder Activity Scale (SAS)) and general health scales (12-Item Short Form Survey (SF-12) and Patient-Reported Outcomes Measurement Information System-Pain Interference). Linear regression models adjusting for age and sex were used to evaluate the association between increasing number of comorbidities and PROM scores. A total of 1,817 shoulder arthroplasties were performed: 1,017 (56%) TSA, 726 (40%) RSA, and 74 (4%) HA. The mean age was 67 years (SD 10), and 936 (52%) of the patients were female. Results. The most common comorbidities were obesity (1,256, 69%) and hypertension (990, 55%). Patients with more comorbidities had lower ASES and SAS scores at baseline (p < 0.001). Elixhauser comorbidities continued to negatively impact ASES and SAS scores at one year (p = 0.002) and two-year follow-up (p = 0.002). Patients with more comorbidities reported greater pain interference on PROMIS at baseline (p = 0.007), but not at two years. Higher number of Charlson comorbidities were associated with lower scores on the SF-12 mental component at baseline (p < 0.001) and two years (p = 0.020). Higher number of Elixhauser comorbidities were associated with lower SF-12 physical component scores at baseline (p < 0.001) and two years (p = 0.004). Conclusion. Higher number of comorbidities was associated with lower baseline scores and worse outcomes on both shoulder-specific and general health PROMs. The presence of specific comorbidities may be used during shared decision-making to manage expectations for patients undergoing shoulder arthroplasty. Cite this article: Bone Joint J 2021;103-B(5):964–970