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Purpose: The aim of this study was to observe the effects of changing humeral tray thickness on the resultant of intraoperative glenohumeral joint loads using a load-sensing system (LSS)., Methods: An rTSA was performed on fresh frozen full-body cadaver shoulders by using an internal proprietary LSS on the humeral side. The glenohumeral loads (Newtons) and the direction of the resultant force applied on the implant were recorded during four standard positions (External rotation, Extension, Abduction, Flexion) and three "complex" positions of Activity Daily Life ("behind back", "overhead reach" and "across chest"). For each position, the thickness was increased from 0 to 6 mm in a continuous fashion using the adjustment feature of the humeral system. Each manoeuvre was repeated three times., Results: All shoulder positions showed a high repeatability of the glenohumeral load magnitude measured with an intra-class correlation coefficient of over 0.9. For each position, we observed a strong but no linear correlation between humeral tray thickness and joint loads. It was a cubical correlation (r s = 0,91) with a short ascending phase, then a plateau phase, and finally a phase with an exponential growth of the loads on the humeral implant. In addition, an increase in trail-poly thickness led to a recentering of force application at the interface of the two glenohumeral implants., Conclusion: This study provides further insight into the effects of humeral implant thickness on rTSA glenohumeral joint loads during different positions of the arm. Data obtained using this type of device could guide surgeons in finding the proper implant balance during rTSA., (© 2024. The Author(s) under exclusive licence to SICOT aisbl.)

Background: Accurate insertion of the glenoid guide pin in shoulder arthroplasty (RSA) is important for obtaining optimized glenoid component position and orientation. The objective of this study was to evaluate and compare the accuracy of 3 glenoid guide pin insertion techniques: (1) traditional software planning using freehand guide pin insertion (freehand), (2) guide pin insertion utilizing patient-specific instrumentation (PSI), and (3) using a mixed-reality navigation (MR-NAV) system., Methods: Twenty (20) computed tomography (CT) scans were obtained from patients exhibiting glenoid erosion patterns according to the Walch and Favard classifications. Cases were planned using validated 3-dimensional (3D) preoperative planning software. The CT data were then used to 3D print triplicate plastic models of each glenoid to evaluate the 3 guide pin insertion techniques. The first technique employed traditional software planning with freehand guide pin insertion. The second method used preoperatively planned PSI guides, whereas the third used an MR-NAV system, which provided real-time holographic guidance during guide pin insertion. Once all guide pins had been inserted into the models, an independent optical tracking system and custom digitization device was used to quantify the position and orientation of each guide pin relative to the glenoid. The outcomes for this study included the absolute mean error in guide pin inclination, version, and entry point relative to the preoperative plan. The absolute Total Global Error was also assessed, which was defined as the sum of the absolute guide pin orientation and position error relative to the preoperative plan., Results: No statistically significant differences between MR-NAV and PSI were found for the inclination error (2° ± 1° vs. 2° ± 1°; P = .056), version error (1° ± 1° vs. 1° ± 1°; P > .99), and Total Global Error (5 ± 1 [mm + deg] vs. 5 ± 1 [mm + deg], P > .99), respectively. The freehand technique produced significantly greater error than MR-NAV and PSI for inclination (5° ± 3°, P ≤ .017), version (4° ± 3°, P ≤ .032), and Total Global Error (8 ± 3 [mm + deg], P < .001). No statistically significant differences in the entry point error were observed between all guide pin insertion methods (P ≥ .058)., Discussion: These results demonstrate that the precision and accuracy of MR-NAV is comparable to PSI and superior to a freehand technique for glenoid guide pin insertion in vitro. Further study is needed to compare the accuracy of these techniques intraoperatively, in addition to assessing a potential learning curve between surgeons of varying experience with the MR-NAV system., (Copyright © 2024 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.)

Introduction: In reverse shoulder arthroplasty (RSA) new designs enable greater amounts of lateralization to prevent instability and scapular notching and increase range of motion, however, excessive lateralization leads to stress upon the acromion that can result in scapular spine fatigue fractures. Aim of this study was to gender- and size-specifically assess the influence of glenosphere size and different humeral designs on lateralization, distalization, and bony impingement-free range of motion (ROM) in patients undergoing RSA., Methods: Computed tomography scans from 30 osteoarthritic patients (f:15, m:15) and 20 cuff tear arthropathy patients (f:10, m:10) were used to virtually simulate RSA implantation. The efficacy of an inlay Grammont-type system vs. an onlay lateralizing system combined with different glenosphere sizes (36 mm vs. 42 mm) in achieving ROM, lateralization, and distalization was evaluated. Moreover, gender and patient's constitution were correlated to humeral size by radiologically measuring the best-fit circle of the humeral head., Results: A different amount of relative lateralization was achieved in both genders using large glenospheres and onlay designs. Latter yielded a higher ROM in all planes for men and women with a 42 mm glenosphere; with the 36 mm glenosphere, an increased ROM was observed only in men. The 155° inlay design led to joint medialization only in men, whereas all designs led to lateralization in women. When adjusting the absolute amount of lateralization to humerus' size (or patient's height), regardless of implant type, women received greater relative lateralization using 36 mm glenosphere (inlay: 1%; onlay 12%) than men with 42 mm glenosphere (inlay: -3%; onlay: 8%)., Conclusion: The relative lateralization achieved using onlay design is much higher in women than men. Small glenospheres yield greater relative lateralization in women compared to large glenospheres in men. Humeral lateralization using onlay designs should be used cautiously in women, as they lead to great relative lateralization increasing stress onto the acromion., Level of Evidence: Basic Science Study, Computer Modeling., (© 2024. The Author(s).)

Purpose: The aim of the present systematic review is to collect all the available evidence regarding the clinical and radiological results of revision to reverse shoulder arthroplasty (RSA) of modular anatomic shoulder prostheses (TSA) using a convertible metal-backed glenoid (MBG)., Methods: This study was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement. Studies investigating revision of TSA to RSA utilizing a convertible MBG and reporting clinical and radiological outcomes were identified., Results: A total of five studies on the use of convertible modular glenoid component in the setting of TSA revision to RSA were finally included in the present systematic review. A total of 60 procedures were reported. Mean operative times was 65 min. Intraoperative complications included 3 cases of glenoid loosening. Only one case of dislocation was reported as postoperative complication. At mean follow-up of 32.3 months post-revision, no glenoid loosening was reported, VAS score decreased from 7.7 to 1.5, Constant Score increased from 24.8 to 57.6., Conclusions: Revision to RSA after failed TSA using a convertible modular glenoid component was associated with a low rate of intraoperative and postoperative complications, low surgical time and led to good results in term of pain relieve and functional outcomes. Given the complexity and risk associated with revision of anatomic shoulder prosthesis having a convertible glenoid may help to simplify the procedure and improve clinical results., (© 2024. The Author(s) under exclusive licence to SICOT aisbl.)

Purpose: Reverse shoulder arthroplasty has demonstrated excellent clinical efficacy for patients with shoulder joint diseases and is increasingly in demand. Traditional surgery faces challenges such as limited exposed surfaces and a narrow field of vision, leading to a shorter prosthesis lifespan and a higher risk of complications. In this study, an optical navigation system was proposed to assist surgeons in real-time tracking of the surgical scene., Methods: Our optical navigation system was developed using the NDI Polaris Spectra device and several open-source platforms. The first step involved using the preoperative medical image to plan screw implantation paths. Real-time tracking of the patient phantom or cadaver and the surgical instrument was achieved through registration and calibration algorithms. Surgeons were guided on drilling through visualization methods. Postoperative results were compared with the planned implantation paths, and an algorithm was introduced to correct errors caused by the incorrect beginning points., Results: Experiments involved three scapula cadavers and their corresponding phantoms with identical anatomy. For each experiment, three holes were completed with drills with diameters of 3.2 mm and 8.0 mm, respectively. Comparisons between the postoperative actual screw implantation paths and the preoperative planned implantation paths revealed an entry error of 1.05 ± 0.15 mm and an angle error of 2.47 ± 0.55° for phantom experiments. For cadaver experiments, the entry error was 1.53 ± 0.22 mm, and the angle error was 4.91 ± 0.78°., Conclusion: Our proposed optical navigation system successfully achieved real-time tracking of the surgical site, encompassing the patient phantom or cadaver and surgical instrument, thereby aiding surgeons in achieving precise surgical outcomes. Future study will explore the integration of robots to further enhance surgical efficiency and effectiveness., (© 2024. CARS.)

Purpose: Good initial fixation of glenoid component for reverse total shoulder arthroplasty (RTSA) relies on component placement and screw purchase in the scapula bone. This is especially difficult in an Asian population with small glenoid geometry. Optimal glenoid component roll angle and screw angulation to achieve the longest screws for best fixation has not been defined in the current literature., Methods: Computer 3D modelling of 133 scapulas with RTSA performed were analyzed to determine patient specific optimal glenoid roll angle (GRA) for the longest bi-cortical screws attainable. The cranial-caudal angle (CCA), anterior-posterior angle (APA) and lengths for the superior and inferior screws were measured. Validation testing using calculated average (CA) angles and rounded average (RA) angles to the nearest 5 degree were recomputed for each case to determine the bi-cortical screw lengths achievable. The CA and RA screw lengths were compared against patient specific modelling using paired-sample t-tests., Results: Average GRA was - 1.6°, almost perpendicular to the long axis of the glenoid and achieves an average bi-cortical screw length of 51.3 mm and 45.5 mm for the superior and inferior screws respectively. The CCA and APA were 9.1° cranial and 6.5° posterior for the superior screw and screw angulation of 11.2° caudal and 0.7° anterior for the inferior screw. Validation testing shows statistically shorter screw lengths in the CA and RA models compared to patient specific modelling (p < 0.01)., Conclusion: Validation testing with average angles for GRA, CCA and APA demonstrates strong patient heterogeneity and anatomical variation. Despite this, screw lengths attainable in the RA group were > 38 mm with good safety profile. Surgeons may consider the additional use of navigation-assisted, or 3D printed patient specific instrumentation to optimize baseplate and screw configuration for RTSA., Competing Interests: Declarations Ethical approval This study was performed in line with the principles of the Declaration of Helsinki. Approval was granted by the Ethics Committee of University of Hong Kong (HKU/HA HKW IRB Reference number: UW 21–111). Informed consent Informed consent was obtained from all individual participants included in the study. Consent for publication All authors consented for publication. Our manuscript did not contain any individual person’s data in any form. Conflict of interest The authors declare they have no conflicts of interests including no relevant financial or non-financial interests to disclose., (© 2024. The Author(s).)

Background: Patient-specific aiming devices (PSAD) may improve precision and accuracy of glenoid component positioning in total shoulder arthroplasty, especially in degenerative glenoids. The aim of this study was to compare precision and accuracy of guide wire positioning into different glenoid models using a PSAD versus a standard guide., Methods: Three experienced shoulder surgeons inserted 2.5 mm K-wires into polyurethane cast glenoid models of type Walch A, B and C (in total 180 models). Every surgeon placed guide wires into 10 glenoids of each type with a standard guide by DePuy Synthes in group (I) and with a PSAD in group (II). Deviation from planned version, inclination and entry point was measured, as well as investigation of a possible learning curve., Results: Maximal deviation in version in B- and C-glenoids in (I) was 20.3° versus 4.8° in (II) (p < 0.001) and in inclination was 20.0° in (I) versus 3.7° in (II) (p < 0.001). For B-glenoid, more than 50% of the guide wires in (I) had a version deviation between 11.9° and 20.3° compared to ≤ 2.2° in (II) (p < 0.001). 50% of B- and C-glenoids in (I) showed a median inclination deviation of 4.6° (0.0°-20.0°; p < 0.001) versus 1.8° (0.0°-4.0°; p < 0.001) in (II). Deviation from the entry point was always less than 5.0 mm when using PSAD compared to a maximum of 7.7 mm with the standard guide and was most pronounced in type C (p < 0.001)., Conclusion: PSAD enhance precision and accuracy of guide wire placement particularly for deformed B and C type glenoids compared to a standard guide in vitro. There was no learning curve for PSAD. However, findings of this study cannot be directly translated to the clinical reality and require further corroboration., (© 2024. The Author(s).)

Competing Interests: The author certifies that there are no funding or commercial associations (consultancies, stock ownership, equity interest, patent/licensing arrangements, etc.) that might pose a conflict of interest in connection with the submitted article related to the author or any immediate family members. All ICMJE Conflict of Interest Forms for authors and Clinical Orthopaedics and Related Research® editors and board members are on file with the publication and can be viewed on request.

Background: Patients who undergo reverse total shoulder arthroplasty (RTSA) are getting younger with greater function expectations. This retrospective, longitudinal study of prospectively collected data compared perceived shoulder function and strength, active shoulder mobility, radiographic evidence of scapular notching, and implant survival over the initial 2-years post-RTSA among patient groups who received either standard central fixation point liner and glenoid baseplate implants, or lower size profile mini-humeral tray with offset trunnion options and mini-augmented glenoid baseplate implants., Materials and Methods: Patients who underwent primary RTSA using standard central fixation point liner and glenoid baseplate implants (Group 1, n = 180) were compared with patients who underwent primary RTSA using lower size profile mini-humeral tray with offset trunnion options and mini-augmented glenoid baseplate implants (Group 2, n = 53) for active shoulder mobility, American Shoulder and Elbow Surgeons (ASES) score, perceived ability to lift 10 lbs (4.5 kg) overhead, radiographic evidence of scapular notching, and implant survival. Data was collected pre-surgery, 6-weeks, 6-months, 1-year, and 2-years post-RTSA (p ≤ 0.05)., Results: More Group 2 patients had more complex B or C Walch glenoid morphology, while Group 1 had more A1 or A2 types (p ≤ 0.001). Group 2 had greater active shoulder flexion at 6-months, 1-year, and 2-years (p ≤ 0.018) and external rotation (in adduction) at 6-months and 2-years (p ≤ 0.004) compared to Group 1, with higher ASES scores at 6-months and 2-years (p ≤ 0.026) (with small-to-medium effect sizes), and with more patients meeting or exceeding the minimal clinically important difference (MCID) at 2-years (p = 0.045) and patient acceptable symptomatic state (PASS) levels at 6-months, 1-year and 2-years (p ≤ 0.045). Scapular notching was identified in six of 53 (11.3%) Group 2 patients and in 32 of 180 (17.7%) Group 1 patients. Group 1 patients had more grade 2 or greater scapular notching grades compared to Group 2 (p = 0.04). Implant survival was comparable with Group 1 = eight of 180 (4.4%) and Group 2 = 1 of 53 (1.9%) of patients requiring removal for 95.6% and 98.1% implant survival, respectively., Conclusion: Limited scapular notching and excellent implant survival was observed in both groups. Despite including individuals with more complex glenoid deficiency, patients receiving the lower size profile implants generally displayed better active shoulder mobility and perceived shoulder function compared to those who received standard implants. These patients also more frequently met or exceeded the MCID by 2-years post-RTSA and PASS levels by 6-months, 1-year, and 2-years post-RTSA, with lower scapular notching grades., Level of Evidence: Retrospective comparative study., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Background: Patient-specific instrumentation (PSI) may potentially improve humeral osteotomy in shoulder arthroplasty. The purpose of this study was to compare the deviation between planned and postosteotomy humeral inclination, retrotorsion, and height in shoulder arthroplasty, using PSI vs. standard cutting guides (SCG)., Methods: Twenty fresh-frozen cadaveric specimens were allocated to undergo humeral osteotomy using either PSI or SCG, such that the 2 groups have similar age, gender, and side. Preosteotomy computed tomography (CT) scan was performed and used for the 3-dimensional (3D) planning. The osteotomy procedure was performed using a PSI designed for each specimen or an SCG depending on the group. A postosteotomy CT scan was performed. The preosteotomy and postosteotomy 3D CT scan reconstructions were superimposed to calculate the deviation between planned and postosteotomy inclination, retrotorsion, and height. Outliers were defined as cases with 1 or more of the following deviations: >5° inclination, >10° retrotorsion, and >3 mm height. The deviation and outliers in inclination, retrotorsion, and height were compared between the 2 groups., Results: The deviations between planned and postosteotomy parameters were similar among the PSI and SCG groups for inclination (P = .260), whereas they were significantly greater in the SCG group for retrotorsion (P < .001) and height (P = .003). There were 8 outliers in the SCG group, compared with only 1 outlier in the PSI group (P = .005). Most outliers in the SCG group were due to deviation >10° in retrotorsion., Conclusion: After 3D planning, PSI had less deviation between planned and postosteotomy humeral retrotorsion and height, relative to SCG., (Copyright © 2022 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.)

The use of uncemented humeral stems in total shoulder arthroplasty (TSA) is associated with stress shielding. Shorter length stems have shown to decrease stress shielding; however, the effect of stem varus-valgus alignment is currently not known. The purpose of this study was to quantify the effect of short stem distal humeral endosteal contact due to varus-valgus angulation on bone stresses after TSA. Three-dimensional models of eight male cadaveric humeri were constructed from computed tomography data. Bone models were reconstructed with a short stem humeral component implant in three positions (standard, varus, and valgus). Modeling was performed at 45° and 75° of abduction and the resulting differentials in bone stress compared to the intact state and the expected time-zero bone response were determined. In cortical and trabecular bone, the standard position (STD) altered bone stress less than the valgus (VAL) and varus (VAR) positions relative to the intact state. For both cortical (p = 0.033) and trabecular (p = 0.012) bone, the VAL position produced a larger volume of bone with resorbing potential compared to the STD position., (© 2021 Orthopaedic Research Society. Published by Wiley Periodicals LLC.)

Background: There has been decreased use of anatomic total shoulder arthroplasty (aTSA) because reverse TSA (rTSA) is increasingly being used for the same indications. Although short-term studies generally have not found survivorship differences between these implant designs, these studies are often small and their follow-up is limited to the short term. Likewise, the degree to which patient characteristics (such as gender, age, and American Society of Anesthesiologists [ASA] score) may or may not be associated with survivorship differences calls for larger and longer-term studies than is often possible in single-center designs. Large national registry studies may be able to help answer these questions., Questions/purposes: By analyzing a large Australian registry series of primary aTSAs with cemented all-polyethylene glenoids and rTSA for osteoarthritis (OA), we asked: (1) Is the revision risk for OA higher for aTSA with all-polyethylene glenoids or for rTSA, adjusting for patient characteristics such as age, gender, ASA score, and BMI? (2) Is the patient's gender associated with differences in the revision risk after controlling for the potentially confounding factors of age, ASA score, and BMI?, Methods: In this comparative, observational registry study performed between January 1, 2015, and December 31, 2019, all primary aTSAs with all-polyethylene glenoids and rTSA for OA as determined by the treating surgeon and reported to our national registry formed two groups for analysis. The study period was set to time-match for the collection of ASA score and BMI in 2012 and 2015, respectively. Our registry enrolls more than 97% of all shoulder arthroplasties undertaken in Australia. There were 29,294 primary shoulder arthroplasties; 1592 hemiarthroplasties, 1876 resurfacing and stemless shoulders, 269 stemmed, and 11,674 reverse shoulder arthroplasties were excluded for other diagnoses. A total of 1210 metal-backed glenoids in stemmed aTSA for OA were excluded. A total of 3795 primary aTSAs with all-polyethylene glenoids and 8878 primary rTSAs for OA were compared. An aTSA with an all-polyethylene glenoid and rTSA were more likely to be performed in women (56% and 61% of patients, respectively). The mean age was 69 ± 8 years for aTSA with all-polyethylene glenoids and 74 ± 8 years for rTSA. One aTSA for OA was performed in a patient with an unknown glenoid type. The ASA score (n = 12,438) and BMI (n = 11,233) were also recorded. The maximum follow-up was 5 years for both groups, and the mean follow-up was 2.6 ± 1.4 years for aTSA with all-polyethylene glenoids and 2.1 ± 1.4 years for rTSA. The endpoint was time to revision (all causes), and the cumulative percent revision was determined using Kaplan-Meier estimates of survivorship (time to revision) and HRs from Cox proportional hazard models that were adjusted for age, gender, ASA score, and BMI category., Results: Overall, there were no differences in the 4-year cumulative percent revision between the groups; the 4-year cumulative percent revision was 3.5% for aTSA with all-polyethylene glenoids (95% CI 2.9%-4.2%) and 3.0% for rTSA (95% CI 2.6%-3.5%). There was an increased risk of revision of rTSA compared with aTSA using all-polyethylene glenoids in the first 3 months (HR 2.17 [95% CI 1.25-3.70]; p = 0.006, adjusted for age, gender, ASA score, and BMI). After that time, there was no difference in the rate of revision, with the same adjustments. In the first 3 months, men undergoing rTSA had a higher rate of revision than men with aTSA using all-polyethylene glenoids (HR 4.0 [95% CI 1.72-9.09]; p = 0.001, adjusted for age, BMI, and ASA). There was no difference between men in the two groups after that time. Women with aTSA using all-polyethylene glenoids were at a greater risk of revision than women with rTSA from 3 months onward (HR 2.77 [95% CI 1.55-4.92]; p < 0.001, adjusted for age, BMI, and ASA), with no difference before that time., Conclusion: Given the absence of survivorship differences at 4 years between rTSA and aTSA, but in light of the differences in the revision risk between men and women, surgeons might select an aTSA with an all-polyethylene glenoid to treat OA, despite the current popularity of rTSA. However, there are survivorship differences between genders. Future studies should evaluate whether our comparative findings are replicated in men and women undergoing aTSA with all-polyethylene glenoids and rTSA for primary diagnoses such as rheumatoid arthritis or post-traumatic arthritis, and whether there are functional differences between the two implant designs when used for OA., Level of Evidence: Level III, therapeutic study., Competing Interests: Each author certifies that there are no funding or commercial associations (consultancies, stock ownership, equity interest, patent/licensing arrangements, etc.) that might pose a conflict of interest in connection with the submitted article related to the author or any immediate family members. All ICMJE Conflict of Interest Forms for authors and Clinical Orthopaedics and Related Research® editors and board members are on file with the publication and can be viewed on request., (Copyright © 2021 by the Association of Bone and Joint Surgeons.)

Background: The purpose of this study was to evaluate glenoid component position and radiolucency following anatomic total shoulder arthroplasty (TSA) using sequential 3-dimensional computed tomography (3D CT) analysis., Methods: In a series of 152 patients (42 Walch A1, 16 A2, 7 B1, 49 B2, 29 B3, 3 C1, 3 C2, and 3 D glenoids) undergoing anatomic TSA with a polyethylene glenoid component, sequential 3D CT analysis was performed preoperatively (CT1), early postoperatively (CT2), and at a minimum 2-year follow-up (CT3). Glenoid component shift was defined as a change in component version or inclination of ≥3° from CT2 to CT3. Glenoid component central anchor peg osteolysis (CPO) was assessed at CT3. Factors associated with glenoid component shift and CPO were evaluated., Results: Glenoid component shift occurred from CT2 to CT3 in 78 (51%) of the 152 patients. CPO was seen at CT3 in 19 (13%) of the 152 patients, including 15 (19%) of the 78 with component shift. Walch B2 glenoids with a standard component and glenoids with higher preoperative retroversion were associated with a higher rate of shift, but not of CPO. B3 glenoids with an augmented component and glenoids with greater preoperative joint-line medialization were associated with CPO, but not with shift. More glenoid component joint-line medialization from CT2 to CT3 was associated with higher rates of shift and CPO. A greater absolute change in glenoid component inclination from CT2 to CT3 and a combined absolute glenoid component version and inclination change from CT2 to CT3 were associated with CPO. Neither glenoid component shift nor CPO was associated with worse clinical outcomes., Conclusions: Postoperative 3D CT analysis demonstrated that glenoid component shift commonly occurs following anatomic TSA, with increased inclination the most common direction. Most (81%) of the patients with glenoid component shift did not develop CPO. Longer follow-up is needed to determine the relationships of glenoid component shift and CPO with loosening over time., Level of Evidence: Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence., Competing Interests: Disclosure: This study was funded by a State of Ohio grant (TIOSO), an Orthopaedic Research and Education Foundation (OREF)/American Shoulder and Elbow Surgeons (ASES) Rockwood Clinical Research Grant (OREF1403ER), and an NIH/NIAMS Research Grant (R01AR075286). On the Disclosure of Potential Conflicts of Interest forms, which are provided with the online version of the article, one or more of the authors checked “yes” to indicate that the author had a relevant financial relationship in the biomedical arena outside the submitted work (http://links.lww.com/JBJS/G459)., (Copyright © 2021 by The Journal of Bone and Joint Surgery, Incorporated.)

For practicing shoulder arthroplasty surgeons, it is advisable to consider a breadth of data sources concerning complications and outcomes. Although published series from high-volume centers are the primary source of data, these results may not be generalizable to a wide range of practice settings. National or health system-specific registry and medical device databases are useful adjuncts to assess the changing complication profile of shoulder arthroplasty, as well as to understand the complications specific to certain implants or implant types. To reduce the risk of postoperative complications, surgeons must have a clear understanding of the most common modes of failure., Competing Interests: Disclosure J.S. Somerson has received support for educational programs from Medinc of Texas, Skeletal Dynamics, Bioventus, Amgen, Smith and Nephew, and ConvaTec. The other authors have nothing to disclose., (Copyright © 2021 Elsevier Inc. All rights reserved.)

Objective: To develop and assess a novel guidance technique and instrumentation system for minimally invasive short-stemmed total shoulder arthroplasty that will help to reduce the complications associated with traditional open replacement such as poor muscle healing and neurovascular injury. We have answered key questions about the developed system including (1) can novel patient-specific guides be accurately registered and used within a minimally invasive environment?; (2) can accuracy similar to traditional techniques be achieved?, Methods: A novel intra-articular patient-specific guide was developed for use with a new minimally invasive posterior surgical approach that guides bone preparation without requiring muscle resection or joint dislocation. Additionally, a novel set of instruments were developed to enable bone preparation within the minimally invasive environment. The full procedure was evaluated in six cadaveric shoulders, using digitizations to assess accuracy of each step., Results: Patient-specific guide registration accuracy in 3D translation was 2.2±1.2mm (RMSE±1 SD; p = 0.007) for the humeral component and 2.7±0.7mm (p<0.001) for the scapula component. Final implantation accuracy was 2.9±3.0mm (p = 0.066) in translation and 5.7-6.8±2.2-4.0° (0.001

Purpose: The purpose of our study was to evaluate the clinical and radiological results of a new anatomic convertible cementless glenoid component., Methods: Forty-eight patients with a mean age of 67.3 years were clinically and radiologically followed-up with a mean of 49 months. Indications for glenoid replacement were A2 glenoid wear in 21.7%, B1 glenoid wear in 28.3%, B2 glenoid wear in 28.3%, B3 glenoid wear in 13%, D glenoid wear in 2.2%, and glenoid component loosening in 6.5%., Results: The Constant-Murley score improved significantly (p < 0.0001) from 50% pre-OP to 103% post-OP. Patients with a B3 glenoid type according to Walch achieved a significant (p = 0.044) lower Constant-Murley Sscore post-OP compared to patients with a B1 glenoid type (88% vs 106%). The mean subluxation index changed significantly (p < 0.0001) from 0.54 pre-OP to 0.46 post-OP. At the metal-back bone interface an incomplete radiolucent line < 1 mm was observed in two cases (4.2%) and an incomplete radiolucent line < 2 mm was observed in another two cases (4.2%). PE dissociation occurred in two cases. No glenoid loosening was observed. The implant related revision rate was 4.2% (2 cases). All components (n = 612.5%) requiring conversion to reverse were converted without any further complications or loosening., Conclusion: Good functional results can be achieved in cases with a B1 and a B2 glenoid after anatomic shoulder arthroplasty using the described metal back glenoid. A conversion from an anatomic to a reverse glenoid component were possible in all cases without any further complications. Conversion of the anatomic glenoid component to a reverse system alleviates revision surgery.

Aims: The purpose of this study was to report bone adaptive changes after anatomical total shoulder arthroplasty (TSA) using a standard-length hydroxyapatite (HA)-coated humeral component, and to report on a computer-based analysis of radiographs to determine changes in peri-implant bone density objectively., Methods: A total of 44 TSAs, performed between 2011 and 2014 using a cementless standard-length humeral component proximally coated with HA, were included. There were 23 males and 21 females with a mean age of 65 years (17 to 65). All shoulders had good quality radiographs at six weeks and five years postoperatively. Three observers graded bone adaptive changes. All radiographs were uploaded into a commercially available photographic software program. The grey value density of humeral radiological areas was corrected to the grey value density of the humeral component and compared over time., Results: Stress shielding was graded as mild in 14 shoulders and moderate in three; the greater tuberosity was the predominant site for stress shielding. The mean metaphyseal and diaphyseal fill-fit ratios were 0.56 (SD 0.1) and 0.5 (SD 0.07), respectively. For shoulders with no radiologically visible stress shielding, the mean decrease in grey value in zones 1 and 7 was 20%, compared with 38% in shoulders with radiologically visible stress shielding., Conclusion: The rate of moderate stress shielding was 7%, five years after implantation of a cementless standard-length HA-coated humeral component. Clinical observation of stress shielding identified on radiographs seems to represent a decrease in grey value of 25% or more. Cite this article: Bone Joint J  2021;103-B(5):958-963.

Reverse shoulder arthroplasty has increased in popularity and has provided improved but somewhat variable results. These variable outcomes may be related to many factors, including implant design, component positioning, specific indication, and patient anatomy. The original Grammont design provided a solution to the high failure rate at the time but was found to have a high rate of scapular notching and poor restoration of rotation. Modern lateralized designs are more consistent in reducing scapular notching while improving range of motion, especially in regards to external rotation. This review article summarizes the effects of modern reverse shoulder prostheses on outcomes., Competing Interests: Disclosure Dr P. Denard: consultant, research support, and royalties, Arthrex; paid speakers bureau, Pacira, Inc. Dr A. Lädermann: paid consultant, Arthrex, Wright, and Medacta and royalties, Wright. Dr J. Callegari, Dr G. Haidamous, Dr C. Phillips, and Mr S. Tracy, their immediate family, and any research foundation with which they are affiliated have not received any financial payments or other benefits from any commercial entity related to the subject of this article., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Background: Cutibacterium acnes is found in skin flora of the shoulder and is the most common microbe identified in periprosthetic shoulder infections. The purpose of this study is to determine if there is C acnes present on the incision scalpel in patients undergoing shoulder arthroplasty despite extensive skin preparation techniques to prevent wound contamination., Methods: The authors collected a consecutive case series of patients meeting inclusion criteria. Patients were included if they underwent either primary or revision shoulder arthroplasty at the tertiary care hospital with the senior author during the study period. Culture swab samples, testing for presence of C acnes, were collected from 17 consecutive patients who underwent shoulder arthroplasty with a single fellowship-trained surgeon between November 2019 and March 2020. Culture reports were recorded as "positive" or "negative" after 21 days. Institutional review board approval of the study protocol was obtained. The null hypothesis was that there would be no cases with knife blades "culture positive" for C acnes., Results: 17 patients were identified and fit inclusion criteria. There were 12 men (mean age 64.3 years, range 48-79 years) and 5 women (mean age 69.8 years, range 59-79 years). Two patients (11.8%) were found to have C acnes growth on the skin knife. Both patients were male and older than 70 years undergoing primary reverse shoulder arthroplasty with no history of previous shoulder infections., Conclusion: The presence of C acnes on the skin blade in 2 patients validates concerns that there is C acnes present in dermal tissue despite extensive attention to eradication of these microbes. There was a high rate of C acnes contamination on scalpel blades used for initial skin incisions and the authors conclude that there is value in discarding these blades from the surgical field., (Copyright © 2020 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.)

Introduction: Shorter humeral reverse total shoulder arthroplasty (RTSA) stems may reduce stress shielding, however, potentially carry the risk of varus/valgus malalignment. This radiographic study's purpose was to measure the incidence of stem malalignment and thus the realized neck-shaft angle (NSA). The hypothesis was that malalignment of the stem is a frequent postoperative radiographic finding., Methods: Radiographs of an uncemented curved short stem RTSA with a 145° NSA were reviewed. The study group included 124 cases at a mean age of 74 (range 48-91) years. The humeral stem axis was measured and defined as neutral if the value fell within ± 5° of the longitudinal humeral axis. Angular values > 5° were defined as malaligned in valgus or varus. The filling ratio of the implant within the humeral shaft was measured at the level of the metaphysis (FR met ) and diaphysis (FR dia )., Results: The average humeral stem axis angle was 4 ± 3° valgus, corresponding to a true mean NSA of 149 ± 3°. Stem axis was neutral in 73% (n = 90) of implants. Of the 34 malaligned implants, 82% (n = 28) were in valgus (NSA = 153 ± 2°) and 18% (n = 6) in varus (NSA = 139 ± 1°). The average FR met  and FR dia were 0.68 ± 0.11 and 0.72 ± 0.11, respectively. A low positive association was found between stem diameter and filling ratios (r = 0.39; p < 0.001); indicating smaller stem sizes were more likely to be misaligned., Conclusion: Uncemented short stem implants may decrease stress shielding; however, approximately one quarter were implanted > 5° malaligned. The majority of malaligned components (86%) were implanted in valgus, corresponding to an NSA of > 150°. As such, surgeons must be aware that shorter and smaller stems may lead to axial malalignment influencing the true SA., Level of Evidence: Level IV, retrospective study.

Background: Revision reverse shoulder arthroplasty (RSA) poses considerable surgical challenges. We hypothesized that a newly developed press-fit stem, which is modeled on the medullary canal of the supracondylar region of the distal humerus by a slight distal bend, achieve both correct fit and sufficient primary stability and that additional distal fixation by interlocking screws is favorable in case of advanced humeral bone loss., Methods: A modular tapered press-fit stem was implanted in 16 Sawbone humeri in three consecutively created defect situations (200 mm (experimental group type 3°), 160 mm (type 4°) and 120 mm (type 5°) bone length above the epicondylar line. In experimental groups type 4° and 5°, additional distal interlocking screw fixation with one to three screws was tested. Primary stability was investigated by measuring micromotions with a high-precision rotational setup., Findings: Highest relative micromotions were noted at the proximal end in experimental groups type 3° and type 4°, whereas in type 5° highest micromotions could be seen at the distal end. Overall micromotions were significantly lower in type 3° and increased with extended defect size. In experimental group type 5°, micromotions increased with reduced additional distal screw fixation., Interpretation: The examined press-fit stem did not provide sufficient primary rotational stability in all constructs without additional support. Advanced distal humeral bone loss had a strong impact on primary fixation. In experimental group type 5° with 120 mm bone remaining, it might be beneficial to use three distal interlocking screws in the supracondylar region in order to neutralize torque and to avoid early loosening., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

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.

Background: Efforts during reverse total shoulder arthroplasty (RSA) have typically focused on maximizing ROM in elevation and external rotation and avoiding scapular notching. Improving internal rotation (IR) is often overlooked, despite its importance for functional outcomes in terms of patient self-care and hygiene. Although determinants of IR are multifactorial, it is unable to surpass limits of bony impingement of the implant. Identifying implant configurations that can reduce bony impingement in a computer model will help surgeons during preoperative planning and also direct implant design and clinical research going forward., Questions/purposes: In a CT-modeling study, we asked: What reverse total shoulder arthroplasty implant position improves the range of impingement free internal rotation without compromising other motions (external rotation and extension)?, Methods: CT images stored in a deidentified teaching database from 25 consecutive patients with Walch A1 glenoids underwent three-dimensional templating for RSA. Each template used the same implant and configuration, which consisted of an onlay humeral design and a 36-mm standard glenosphere. The resulting constructs were virtually taken through ROM until bony impingement was found. Variations were made in the RSA parameters of baseplate lateralization, glenosphere size, glenosphere overhang, humeral version, and humeral neck-shaft angle. Simulated ROM was repeated after each parameter was changed individually and then again after combining multiple changes into a single configuration. The impingement-free IR was calculated and compared between groups. We also evaluated the effect on other ROM including external rotation and extension to ensure that configurations with improvements in IR were not associated with losses in other areas., Results: Combining lateralization, inferiorization, varus neck-shaft angle, increased glenosphere size, and increased humeral anteversion resulted in a greater improvement in internal rotation than any single parameter change did (median baseline IR: 85° [interquartile range 73° to 90°]; combined changes: 119° [IQR 113° to 121°], median difference: 37° [IQR 32° to 43°]; p < 0.001)., Conclusion: Increased glenosphere overhang, varus neck-shaft angle, and humeral anteversion improved internal rotation in a computational model, while glenoid lateralization alone did not. Combining these techniques led to the greatest improvement in IR., Clinical Relevance: This computer model study showed that various implant changes including inferiorization, varus neck-shaft angle, increased glenosphere size, and increased humeral anteversion can be combined to increase impingement-free IR. Surgeons can employ these currently available implant configurations to improve IR when planning and performing RSA. These findings support the need for further clinical studies validating the effect of implant configuration on resultant IR., Competing Interests: Each author certifies that neither he, nor any member of his immediate family, has funding or commercial associations (consultancies, stock ownership, equity interest, patent/licensing arrangements, etc.) that might pose a conflict of interest in connection with the submitted article. All ICMJE Conflict of Interest Forms for authors and Clinical Orthopaedics and Related Research® editors and board members are on file with the publication and can be viewed on request., (Copyright © 2020 by the Association of Bone and Joint Surgeons.)

Background: Despite rapid increases in the demand for total shoulder arthroplasty, data describing cost trends are scarce. We aim to (1) describe variation in the cost of shoulder arthroplasty performed by different surgeons at multiple hospitals and (2) determine the driving factors of such variation., Methods: A standardized, highly accurate cost accounting method, time-driven activity-based costing, was used to determine the cost of 1571 shoulder arthroplasties performed by 12 surgeons at 4 high-volume institutions between 2016 and 2018. Costs were broken down into supply costs (including implant price and consumables) and personnel costs, including physician fees. Cost parameters were compared with total cost for surgical episodes and case volume., Results: Across 4 institutions and 12 surgeons, surgeon volume and hospital volume did not correlate with episode-of-care cost. Average cost per case of each institution varied by factors of 1.6 (P = .47) and 1.7 (P = .06) for anatomic total shoulder arthroplasty (TSA) and reverse total shoulder arthroplasty (RSA), respectively. Implant (56% and 62%, respectively) and personnel costs from check-in through the operating room (21% and 17%, respectively) represented the highest percentages of cost and highly correlated with the cost of the episode of care for TSA and RSA., Conclusions: Variation in episode-of-care total costs for both TSA and RSA had no association with hospital or surgeon case volume at 4 high-volume institutions but was driven primarily by variation in implant and personnel costs through the operating room. This analysis does not address medium- or long-term costs., (Copyright © 2020 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.)

Background: Patients with a patient-reported penicillin allergy may be at greater risk for postoperative prosthetic joint infection (PJI) after total joint arthroplasty of the hip, knee, or shoulder. The increased risk of PJI in these patients has been attributed to these patients receiving a less-effective perioperative antibiotic. However, prior reports did not fully address the clinical characteristics of these unique patients, who may inherently be at greater risk of having a PJI, which may confound prior findings., Questions/purposes: After controlling for risk factors for PJI such as BMI, anxiety, depression, and other comorbidities, we asked: Are patients with a patient-reported penicillin allergy more likely to have a PJI after THA, TKA, or total shoulder arthroplasty than patients without such a reported allergy?, Methods: We queried patient records from 2010 to 2017 from a nationwide administrative claims database of 122 million patients to adequately power an investigation comparing the 1-year incidence of PJI after TKA, total shoulder arthroplasty, and THA in patients with patient-reported penicillin allergy versus patients without a patient-reported penicillin allergy. Operative treatments for deep joint infection, identified by Current Procedural Terminology and ICD-9 and ICD-10 codes were used as a surrogate for PJI. Clinical characteristics such as age, sex, BMI, length of stay, and Charlson comorbidity index and specific comorbidities including alcohol abuse, anemia, anxiety, cardiac disease, diabetes, immunocompromised status, rheumatoid arthritis, depression, liver disease, chronic kidney disease, tobacco use, and peripheral vascular disease were queried for each study group. The odds of PJI within 1 year of THA, TKA, or total shoulder arthroplasty were compared using multiple logistic regression after adjusting for potential confounders., Results: After adjusting for potential confounding factors such as BMI, anxiety, depression and other comorbidities, we found that patient-reported penicillin allergy was independently associated with an increased odds of PJI after TKA (odds ratio 1.3 [95% confidence interval 1.1 to 1.4]; p < 0.01) and total shoulder arthroplasty (OR 3.9 [95% CI 2.7 to 5.4]; p < 0.01). However, patient-reported penicillin allergy was not independently associated with an increased odds of PJI after THA (OR 1.1 [95% CI 0.9 to 1.3]; p = 0.36) after controlling for the same risk factors., Conclusions: In this study, we found that patients with patient-reported penicillin allergy were at an increased risk for PJI after TKA and total shoulder arthroplasty, which we suspect-but cannot prove-is likely a function of those patients receiving a second-line antibiotic for presurgical prophylaxis. Since prior research has found that many patients listed in medical records as having a penicillin allergy are in fact not allergic to penicillin, we suggest that surgeons consider preoperative allergy testing, such as using an intraoperative test dose, to aid in choosing the most appropriate antibiotic choice before knee or shoulder arthroplasty and to amend patient medical records based on testing results. Future studies should determine whether this additional diagnostic maneuver is cost-effective., Level of Evidence: Level III, therapeutic study.

Background: Stemless humeral components for anatomic total shoulder arthroplasty (aTSA) have several reported potential benefits compared with stemmed implants. However, we are aware of no Level-I, randomized controlled trials (RCTs) that have compared stemless implants with stemmed implants in patients managed with aTSA. We sought to directly compare the short-term clinical and radiographic outcomes of stemless and stemmed implants to determine if the stemless implant is noninferior to the stemmed implant., Methods: We performed a prospective, multicenter, single-blinded RCT comparing stemless and short-stemmed implants in patients managed with aTSA. Range-of-motion measurements and American Shoulder and Elbow Surgeons (ASES), Single Assessment Numeric Evaluation (SANE), and Constant scores were obtained at multiple time points. Device-related complications were recorded. Radiographic evaluation for evidence of loosening, fractures, dislocation, or other component complications was performed. Statistical analysis for noninferiority was performed at 2 years of follow-up for 3 primary end points: ASES score, absence of device-related complications, and radiographic signs of loosening. All other data were compared between cohorts at all time points as secondary measures., Results: Two hundred and sixty-five shoulders (including 176 shoulders in male patients and 89 shoulders in female patients) were randomized and received the allocated treatment. The mean age of the patients (and standard deviation) was 62.6 ± 9.3 years, and 99% of the shoulders had a primary diagnosis of osteoarthritis. At 2 years, the mean ASES score was 92.5 ± 14.9 for the stemless cohort and 92.2 ± 13.5 for the stemmed cohort (p value for noninferiority test, <0.0001), the proportion of shoulders without device-related complications was 92% (107 of 116) for the stemless cohort and 93% (114 of 123) for the stemmed cohort (p value for noninferiority test, 0.0063), and no shoulder in either cohort had radiographic signs of loosening. Range-of-motion measurements and ASES, SANE, and Constant scores did not differ significantly between cohorts at any time point within the 2-year follow-up., Conclusions: At 2 years of follow-up, the safety and effectiveness of the stemless humeral implant were noninferior to those of the stemmed humeral implant in patients managed with aTSA for the treatment of osteoarthritis. These short-term results are promising given the potential benefits of stemless designs over traditional, stemmed humeral components., Level of Evidence: Therapeutic Level I. See Instructions for Authors for a complete description of levels of evidence.

Background: Little is known about the way the newest generation of stems integrate into the proximal humerus and their effect on the surrounding bone. Factors that may influence ingrowth have not been investigated., Methods: A consecutive cohort study was conducted that examined 74 anatomical, reverse, or pyrocarbon hemiprostheses, using a curved modular short stem with a proximal porous coating 2-5 years postoperatively (mean 35 months). X-rays were reviewed by 2 examiners independently. Bone loss was scored with 1 point per zone with partial and 2 points per zone with complete resorption (10 zones). The Constant score was used for clinical correlation. Multiple linear regression was employed to investigate correlations between variables., Results: No subsidence or shift of the stems occurred. Two of 74 patients showed 1 zone of periprosthetic lucency of 1 mm. The filling ratio averaged 0.54 (range: 0.36-0.75). Thirty patients (40.5%) displayed bone resorption, first seen at 16.6 months (range: 3-40 months), commonly in zones 1 and 5. A total of 22 patients had ≥1 zone with partial resorption, and 8 (10.8%) developed full thickness resorption after 32 (range: 10-49) months.One new finding was that female sex and older age accounted for 51% of the variation of the filling ratio. A high filling ratio, especially when >0.55, correlated with bone resorption (P < .001). Age, sex, and prosthesis type did not directly predict bone resorption. Bony sclerosis correlated with a high filling ratio (P = .019) and thereby indirectly with resorption. A direct correlation between sclerosis and resorption was narrowly insignificant (P = .058) once correcting for the filling ratio. Reverse shoulder prosthesis had a higher filling ratio than total shoulder prosthesis patients (P < .001), resulting indirectly in more bone resorption. The preoperative diagnosis did not significantly correlate with the filling ratio (P = .59) or the resorption score (P = .69). A varus or valgus alignment did not predict resorption (P = .21) or the formation of sclerotic lines (P = .93). Bone loss did not correlate with clinical results., Conclusions: These short stems are firmly anchored 2-5 years postoperatively. However, significant bone loss, linked to a high filling ratio (>0.55), is observed proximally around these stems. The development of sclerotic lines around the stem indicates oversizing. Other factors were not found to have a significant effect on stem ingrowth. The implantation of stems with a large filling ratio is more common in older females and in patients receiving reverse shoulder prosthesis. Autologous impaction bone grafting could downsize the required stem. If adequate hold is not afforded by a suitably small stem, cementation is advisable., (Copyright © 2020 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.)

Background: Glenoid component loosening remains an important concern in anatomic total shoulder arthroplasty. The aim of this study was to evaluate the clinical and radiographic results of a fully uncemented all-polyethylene fluted central peg bone-ingrowth glenoid component at a minimum 5-year follow-up., Methods: Thirty-five shoulders in 31 patients (mean age, 73 years) with a mean follow-up of 100 months were retrospectively evaluated at an early and mid-term time point for Constant score (CS). Computed tomography visualized glenoid component fixation at both time points., Results: Mean CS improved from 40 preoperatively to 66 postoperatively at latest follow-up (P < .001). A mean CS of 74 at early follow-up remained consistent with a mean CS of 66 at latest follow-up (P = .158), with only strength demonstrating a decrease over time (P < .001). An initial osseointegration rate of 81% at early follow-up decreased to 71% at latest follow-up with 74% of the shoulders demonstrating progressive radiolucent lines, resulting in a radiographic loosening rate of 31%. Of the 35 shoulders, 4 were revised (survival rate of 88%), of which 2 due to symptomatic aseptic loosening., Conclusions: Uncemented fixation of an all-polyethylene central peg bone-ingrowth glenoid was associated with satisfactory clinical and radiographic scores, and an acceptable revision rate at mid- to long-term follow-up. Despite initial bony osseointegration in the majority of cases, radiographic loosening over time remains a concern, potentially jeopardizing long-lasting fixation of this type of glenoid component when implanted in an off-label uncemented fashion., (Copyright © 2020 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.)

Background: The use of reverse total shoulder arthroplasty (RTSA) has dramatically increased in recent years with the advent of new prosthesis designs regularly entering the market. We define the rate of local complications during the first 2 years after RTSA with the Univers Revers prosthesis and describe the changes in radiologic outcomes, as well as function, pain, satisfaction, and quality of life., Methods: This multicenter, prospective case series included rotator cuff tear arthropathy patients who underwent RTSA with the Univers Revers. Incidence percentages of complications and pathologic radiographic changes were documented. Mixed-model linear regression was used to examine changes in range of motion, shoulder function (Constant score, Shoulder Pain and Disability Index, Subjective Shoulder Value), and quality of life (EQ-5D-5L [European Quality of Life 5 Dimensions 5 Level] and EQ-VAS [EuroQol Visual Analog Scale])., Results: Of 187 patients, 59.4% were women, and the mean age was 75.3 years (range, 56-91 years). Twenty-five percent of patients had a postoperative complication; 5 complications were severe (2.7%, 5 of 187), whereby 2 were implant related (1.1%; 95% confidence interval [CI], 0.1%-3.8%). The incidence of scapular notching was 10.6% (95% CI, 6.5%-16%). After 2 years, abduction, flexion, and abduction strength improved by 54° (95% CI, 50°-58°), 57° (95% CI, 53°-60°), and 5 kg (95% CI, 4-5 kg), respectively (P < .001), whereas external rotation at 0° (1°; 95% CI, -1° to 3°) did not improve (P = .4). The Constant score improved by 39 (95% CI, 38-41); Shoulder Pain and Disability Index, by 50 (95% CI, 47-52); and Subjective Shoulder Value, by 43 (95% CI, 41-45) (P < .001). Furthermore, the EQ-5D-5L index value improved by 0.31 (95% CI, 0.30-0.33), and the EQ-VAS score improved by 16 (95% CI, 14-18) (P < .001)., Conclusion: Our case series showed a low complication rate with a consistent clinically relevant and statistically significant improvement across most clinical and patient-reported outcomes for the Univers Revers. Long-term safety requires further investigation., (Copyright © 2020 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.)

Cases: Two patients presented to different surgeons complaining of persistent shoulder pain after reverse total shoulder arthroplasty. Workups for fracture, instability, and periprosthetic infection were negative. Advanced imaging, nerve conduction studies, and diagnostic injections localized symptoms to the suprascapular nerve. Revision arthroplasty with removal of the offending screws improved pain in both patients., Conclusion: Suprascapular nerve irritation because of the malposition of baseplate screws in reverse total shoulder arthroplasty can be a source of postoperative pain. Removal of the offending screw without formal nerve exploration may result in symptomatic improvement., Competing Interests: Disclosure: The Disclosure of Potential Conflicts of Interest forms are provided with the online version of the article (http://links.lww.com/JBJSCC/B292)., (Copyright © 2020 by The Journal of Bone and Joint Surgery, Incorporated.)

Introduction: Preoperative 3D planning programs for anatomic (TSA) and reverse total shoulder arthroplasty (RSA) allow the analysis of glenohumeral joint pathoanatomy and templating for implant size selection and placement. The aim of this multicenter study was to compare the preoperative glenoid implant type and size planned to the final glenoid implant type and size used intraoperatively., Methods: Two hundred patients (100 TSA and 100 RSA) with a mean age of 72 years who had undergone preoperative planning and subsequent shoulder arthroplasty (100 TSA and 100 RSA) were included. All preoperative plans were saved and were analyzed for arthroplasty type (TSA vs. RSA), implant type (augment vs. nonaugment), and size (ie, polyethylene size, polyethylene radius of curvature, glenoid baseplate diameter, baseplate post length, and baseplate lateralization). The preoperative plan was available during surgery and was compared to the final implants inserted by the surgeon., Results: There were no intraoperative conversions of TSA to RSA or vice versa. In patients planned for a TSA, complete concordance between the preoperative plan and final implant selection was 85%. A complete mismatch for TSA glenoid size, backside radius of curvature, and augmentation occurred in 2%. For RSA, complete concordance was found in 90% of cases. A complete mismatch for implant type, size, post length, and glenosphere size occurred in 3%., Conclusion: A high concordance was found between preoperative 3D planning implant selection and the glenoid component inserted at surgery for TSA and RSA. This high concordance may assist with surgical preparedness, implant stocks, and possibly future implant production., (Copyright © 2020 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.)

Background: Glenoid lateralization has been shown to be the most imortant factor in maximizing passive range of motion and shoulder stability while preventing scapular impingement and notching. We aimed to evaluate mid- to long-term functional and radiologic outcomes after bony increased-offset-reverse shoulder arthroplasty (BIO-RSA) using a Grammont-style (medialized) humeral implant., Methods: The study included 143 consecutive shoulders (140 patients; mean age, 72 years) treated with a BIO-RSA for rotator cuff deficiency. A cylinder of autologous cancellous bone graft, harvested from the humeral head, was placed between the reamed glenoid surface and baseplate; fixation was achieved using a long central peg (25 mm) and 4 screws. A large baseplate (29 mm) with a small baseplate sphere (36 mm) was used in 77% of cases, and a Grammont-style (medialized) humeral implant with 155° of inclination was used in all cases. All patients underwent clinical and radiographic assessment at a minimum of 5 years after surgery; in addition, 86 cases (60%) underwent computed tomography scan assessment., Results: At a mean follow-up of 75 months (range, 60-126 months), the survivorship of the BIO-RSA using revision as an endpoint was 96%. No cases of dislocation or humeral loosening were observed. Overall, 118 patients (83%) were either very satisfied (61%) or satisfied (22%). The adjusted Constant score improved from 40% ± 18% to 93% ± 23%, and the Subjective Shoulder Value improved from 31% ± 15% to 77% ± 18% (P < .001). The humeral bone graft incorporated completely in 96% of cases (137 of 143). Severe inferior scapular notching (grade 3 or 4) occurred in 18% (24 of 136). The risk of postoperative notching correlated to a lower body mass index (P < .05), superior glenosphere inclination (P = .02), and high or flush glenosphere positioning (P = .035)., Conclusions: BIO-RSA is a safe and effective technique to lateralize the glenoid, providing consistent bone graft healing, excellent functional outcomes, a low revision rate, and a high rate of patient satisfaction. Thin patients (with a low body mass index) and glenosphere malposition (with persistent superior inclination and/or insufficient lowering of the baseplate and sphere) are associated with higher risk of scapular notching.Our data confirm the importance of implanting the baseplate with a neutral inclination (reverse shoulder arthroplasty angle < 5°) and with sufficient glenosphere inferior overhang (>5 mm) in preventing scapular notching. The use of a less medialized humeral implant (135° or 145° inclined) and smaller (25-mm) baseplate (when using a small, 36-mm sphere) should allow reduction in the incidence of scapular notching., (Copyright © 2020. Published by Elsevier Inc.)

Background: Many options exist for reconstructing the shoulder after large bony resections of the proximal humerus. One of the more widely used is endoprosthetic replacement. Proximal migration of unconstrained hemiarthroplasty articulations may cause difficulties particularly in the setting of loss of the rotator cuff and/or deltoid musculature. To attempt to overcome these issues, a fixed-fulcrum constrained reverse shoulder replacement option may be considered., Methods: A retrospective review of prospectively collected data from the Queensland Bone and Soft Tissue Sarcoma Service was undertaken to compare the function, implant survivorship, and reoperation rate of constrained reverse and unconstrained hemiarthroplasty-type endoprostheses in patients with tumors., Results: We retrospectively reviewed data on 41 consecutive proximal or total humeral endoprosthetic replacements undertaken between January 2003 and July 2018. One patient was excluded as lost to follow-up prior to 24 months. There were 21 unconstrained implants and 19 constrained shoulder replacements (Stanmore Modular Endoprosthesis Tumour System with Bayley-Walker articulation). Proximal migration of the unconstrained hemiarthroplasty articulation occurred in 8 patients (38%), and dislocation or failure of the constrained mechanism occurred in 5 (26%). Reoperation for implant-related issues was required in 5 patients in the constrained group and none in the unconstrained group. Of the 18 patients alive at the time of review, 12 provided functional scores. The mean follow-up period for surviving patients was 4.2 years (standard deviation, 2.7 years), with a minimum of 2 years' follow-up. Functional scores were similar between the 2 groups., Conclusion: Constrained reverse prostheses were associated with a higher reoperation rate in this series without any functional benefit compared with unconstrained hemiarthroplasty-type articulations. We favor the use of unconstrained hemiarthroplasty-type endoprostheses for reconstruction after resection of destructive lesions of the proximal humerus., (Copyright © 2020 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.)

Introduction: Anatomic total shoulder arthroplasty (TSA) is a proven treatment for glenohumeral joint osteoarthritis, with superior results compared with hemiarthroplasty. However, glenoid component loosening remains a problem and is one of the most common causes of failure in TSA. Multiple component designs have been developed in an attempt to reduce loosening rates. The purpose of this study was to evaluate risk of revision after anatomic TSA according to the glenoid component design., Methods: We conducted a cohort study including patients aged ≥18 years who underwent primary elective TSA for the diagnosis of osteoarthritis between 2010 and 2017. Patients with missing implant information, who received stemless humeral implants, or who received augmented glenoid implants, were excluded. Glenoid component designs used were categorized into 4 mutually exclusive treatment groups: polyethylene central-pegged ingrowth, polyethylene-metal hybrid, polyethylene all-cemented pegged, and polyethylene cemented keeled. Multivariable competing risk regression was used to evaluate the risk of glenoid loosening as a cause-specific revision by the glenoid component design., Results: Of the 5566 TSA included in the final cohort, 39.2% of glenoid implants were polyethylene central-pegged ingrowth, 31.1% were polyethylene-metal hybrid, 26.0% were polyethylene all-cemented pegged, and 3.6% were polyethylene cemented keeled. At 6-year final follow-up, 4.1% of TSA were revised for any cause, and 1.4% for glenoid loosening. Compared with the polyethylene central-pegged ingrowth design, no difference in glenoid loosening revision risk was observed for the polyethylene-metal hybrid design (hazard ratio [HR] = 1.15, 95% confidence interval [CI] = 0.42-3.20). However, both the polyethylene all-cemented pegged (HR = 2.48, 95% CI = 1.08-5.66) and polyethylene cemented keeled (HR = 3.84, 95% CI = 1.13-13.00) designs had higher risks for revision due to glenoid loosening., Conclusions: We observed glenoid component designs to be associated with differential risks in revision due to glenoid loosening with polyethylene all-cemented pegged glenoids and polyethylene cemented keeled glenoids having higher risks when compared with polyethylene central-pegged ingrowth glenoids. Surgeons may want to consider the glenoid component design when performing anatomic TSA., (Copyright © 2020 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.)

Background: Preoperative planning software is gaining utility in reverse total shoulder arthroplasty (RTSA), particularly when addressing pathologic glenoid wear. The purpose of this study was to quantify inter- and intrasurgeon variability in preoperative planning a series of RTSA cases to identify differences in how surgeons consider optimal implant placement. This may help identify opportunities to establish consensus when correlating plan differences with clinical data., Methods: A total of 49 computed tomography scans from actual RTSA cases were planned for RTSA by 9 fellowship-trained shoulder surgeons using the same platform (Exactech GPS, Exactech Inc., Gainesville, FL, USA). Each case was planned a second time 6-12 weeks later. Variability within and between surgeons was measured for implant selection, version correction, inclination correction, and implant face position. Interclass correlation coefficients, and Pearson and Light's kappa coefficient were used for statistical analysis., Results: There was considerable variation in the frequency of augmented baseplate selection between surgeons and between rounds for the same surgeon. Thresholds for augment use also varied between surgeons. Interclass correlation coefficients for intersurgeon variability ranged from 0.43 for version, 0.42 for inclination, and 0.25 for baseplate type. Pearson coefficients for intrasurgeon variability were 0.34 for version and 0.30 for inclination. Light's kappa coefficient for baseplate type was 0.61., Conclusions: This study demonstrates substantial variability both between surgeons and between rounds for individual surgeons when planning RTSA. Although average differences between plans were relatively small, there were large differences in specific cases suggesting little consensus on optimal planning parameters and opportunities to establish guidelines based on glenoid pathoanatomy. The correlation of preoperative planning with clinical outcomes will help to establish such guidelines., (Copyright © 2020 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.)

Background: Stemless anatomic total shoulder arthroplasty (TSA) is used in the treatment of osteoarthritis of the shoulder joint and other degenerative shoulder diseases. It has several proposed advantages over stemmed TSA including increased bone preservation, decreased operative time, and easier removal at revision., Methods: A systematic search was conducted using MEDLINE, Embase, PubMed, and CENTRAL (Cochrane Central Register of Controlled Trials) to retrieve all relevant studies., Results: The literature search yielded 1417 studies, of which 22 were included in this review, with 962 patients undergoing stemless TSA. Stemless TSA led to significant improvements in range of motion and functional scores in all included studies. Meta-analysis of comparative studies between stemless and stemmed TSA identified no significant differences in postoperative Constant scores (mean difference [MD], 1.26; 95% confidence interval [CI], -3.29 to 5.81 points; P = .59) or complication rates (odds ratio, 1.79; 95% CI, 0.71-4.54; P = .22). Stemless TSA resulted in a significantly shorter operative time compared with stemmed TSA (MD, -15.03 minutes; 95% CI, -23.79 to -6.26 minutes; P = .0008). Stemless TSA also resulted in significantly decreased intraoperative blood loss compared with stemmed TSA (MD, -96.95 mL; 95% CI, -148.53 to -45.36 mL; P = .0002)., Conclusion: Stemless anatomic TSA resulted in similar functional outcomes and complication rates to stemmed TSA with decreased operative time and lower blood loss. Further research is required to investigate the long-term durability of the stemless implant., (Copyright © 2020 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.)

Background: Inaccurate fixation and positioning of the glenoid component using conventional techniques are problematic in reversed shoulder arthroplasty (RSA). Our objective was to investigate the accuracy of O-arm navigation of the glenoid component in RSA., Methods: This retrospective case-control study comprised 2 groups of 25 patients who underwent reversed shoulder arthroplasty with or without intraoperative O-arm navigation. The intraoperative goal was to place the component neutrally in the glenoid in the axial plane and 10° inferiorly tilted in the scapular plane. Glenoid version angle and inclination were measured by computed tomography obtained preoperatively and a year postoperatively. Operative time, intraoperative bleeding, and the presence of postoperative complications were recorded., Results: Compared with the ideal, the range of error for version was 7.3° (SD 3.6°) in the control group and 5.6° (SD 3.6°) in the navigated group (P = 0.278), and the range of error for inclination was 18.3° (SD 11.7°) in the control group and 4.9° (SD 3.8°) in the navigated group (P = 0.0004). The mean operative time was 164.6 (SD 21.2) min in the control group and 192.0 (SD 16.2) min in the navigated group (P = 0.001). The mean intraoperative bleeding was 201.0 (SD 37.0) mL in the control group and 185.3 (SD 35.6) mL in the navigated group (P = 0.300). There were no complications reported related to the intraoperative O-arm navigation., Conclusion: O-arm navigation may be a useful tool for the placement with inferior tilt of the glenoid procedure in reversed shoulder arthroplasty., Competing Interests: Declaration of Competing Interest None., (Copyright © 2019. Published by Elsevier B.V.)

Background: Concerns exist regarding the complication rates and implant survivorship of reverse total shoulder arthroplasty (RTSA) in younger patients., Methods: A systematic review of the literature regarding the existing evidence on RTSA in patients younger than 65 years was performed using the CENTRAL (Cochrane Central Register of Controlled Trials), PubMed, and Embase databases on June 9, 2019. Articles published between 1995 and 2019 with combinations of the following keywords were identified: "reverse shoulder arthroplasty" and "65," "60," and/or "55." Complications, reoperations, and revisions were recorded. Reoperation-free survival and implant survival rates were grouped at 2, 5, and 10 years. Range of motion and clinical outcomes, along with postoperative radiographic results, were recorded., Results: Data from 7 studies with a total of 286 shoulders were obtained for quantitative analysis. The mean patient age was 58.4 years (mean age range, 48.9-60.4 years), and the mean follow-up period was 4.7 years (mean follow-up range, 3.0-7.8 years). The overall rate of complications was 18.6%; reoperations, 14.4%; and revisions, 11.2%. The reoperation-free survival rate was 97% at 2 years, 88%-90% at 5 years, and 76% at 10 years. The implant survival rate was 99% at 2 years, 91%-98% at 5 years, and 88% at 10 years. Active abduction, forward elevation, and external rotation significantly improved from preoperatively to postoperatively. All clinical outcome measures significantly improved from preoperatively to postoperatively, with no decline seen over time. The overall rate of infrascapular notching was 22.7% at final follow-up., Conclusion: RTSA is safe and effective in patients younger than 65 years. Complication, reoperation, and revision rates were similar to those seen in older patient cohorts, without an increase in revisions owing to aseptic loosening. Clinical outcome scores showed significant and lasting improvements., (Copyright © 2020 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.)

Background: Reverse shoulder arthroplasty is quickly becoming the most frequently performed glenohumeral joint replacement. The purpose of this study was to evaluate the volumetric and linear wear rates of ultrahigh-molecular-weight polyethylene humeral liners in vivo at a minimum 5-year follow-up., Methods: Radiostereometric analysis was used to image 15 patients at terminal range of motion in forward flexion, abduction, external rotation, and internal rotation and with the arm at the side. The relative position and orientation of the glenosphere and polyethylene were identified for each arm position. The apparent intersection of the glenosphere into the polyethylene was recorded as wear. Mean volumetric and linear wear rates were recorded, and Pearson correlation coefficients were applied to the 36-mm liners to assess the relationship between the wear rate and term of service., Results: The mean reverse shoulder arthroplasty term of service at the time of imaging was 8 ± 1 years (range, 6-11 years). The mean volumetric and linear wear rates for the 36-mm liners (n = 13) were 42 ± 22 mm 3 /yr (r = 0.688, P = .009) and 0.11 ± 0.03 mm/yr (r = 0.767, P = .002), respectively. The mean volumetric and linear wear rates for the 42-mm liners (n = 2) were 114 ± 44 mm 3 /yr and 0.17 ± 0.01 mm/yr, respectively. No single arm position was able to capture all recorded wear individually., Conclusion: This study showed volumetric and linear wear rates of approximately 40 mm 3 /yr and 0.1 mm/yr, respectively, for the 36-mm polyethylene liners. The 42-mm liners showed higher wear rates, although a greater number of subjects is required for conclusive results. In vivo wear of reverse total shoulder arthroplasty is multidirectional and perceptible., (Crown Copyright © 2020. Published by Elsevier Inc. All rights reserved.)

Background: The purpose of this study was to compare long-term outcomes, complications, and reoperation rates of primary reverse total shoulder arthroplasty (RTSA) performed at a single institution using 2 implant designs: a Grammont medialized prosthesis (medialized [M] group) and a Frankle glenoid-based lateralized prosthesis (glenoid-lateralized [GL] group)., Methods: Between 2004 and 2008, 100 consecutive single-institution primary RTSAs were performed by reconstructive shoulder surgeons who were not design consultants, with the aim of obtaining 10-year follow-up: 56 in the M group and 44 in the GL group. Patients were followed up until death, until revision surgery, or for a minimum of 10 years., Results: Of 100 patients, 87 had more than 2 years' follow-up (mean, 77 months). A subset analysis of 41 patients with an average of 10.2 years' follow-up showed sustained long-term outcomes. RTSA provided clinical improvements without significant differences between the M and GL groups, except for improved active forward elevation in the M group (144° in M group vs. 115° in GL group, P = .002). Reoperation was required in 6 shoulders (10-year cumulative incidence of 3 [5%] in M group vs. 3 [8%] in GL group) for a total of 16 complications (10-year cumulative incidence of 8 [14%] in M group vs. 8 [20%] in GL group). Notching rates were significantly higher in the M group (77% in M group vs. 47% in GL group, P = .013); differences in severe notching (grade 3 or 4) were clinically relevant but did not reach statistical significance (23% in M group vs. 9% in GL group, P = .22)., Conclusion: Primary RTSA using these first 2 prosthesis designs was associated with good outcomes and low reoperation (5%-8%) and complication (14%-20%) rates at 10 years. The M group had higher rates of notching. These results may provide a benchmark for comparison with newer implants, especially considering that these results include the early RTSA implantation learning curve., (Copyright © 2019 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.)

Background: Reverse total shoulder arthroplasty (rTSA) in the presence of significant glenoid bone loss remains a challenge. This study presents preliminary clinical and radiographic outcomes of primary and revision rTSA using a patient-matched, 3-dimensionally printed custom metal glenoid implant to address severe glenoid bone deficiency., Methods: Between September 2017 and November 2018, 19 patients with severe glenoid bone deficiency underwent primary (n = 9) or revision rTSA (n = 10) using the Comprehensive Vault Reconstruction System (VRS) (Zimmer Biomet, Warsaw, IN, USA) at a single institution. Preoperative and postoperative values for the Disabilities of the Arm, Shoulder and Hand score, Constant score, American Shoulder and Elbow Surgeons score, Simple Shoulder Test score, Single Assessment Numeric Evaluation score, and visual analog scale pain score and active range of motion were compared using the Wilcoxon signed rank test with the level of statistical significance set at P < .05., Results: Complications occurred in 4 patients (21%), including a nondisplaced greater tuberosity fracture treated conservatively in 1, intraoperative cortical perforation during humeral cement removal treated with an allograft strut in 1, and recurrent instability and hematoma formation treated with humeral component revision in 1. One patient with an early periprosthetic infection was treated with component removal and antibiotic spacer placement at an outside facility and was subsequently lost to follow-up. Eighteen patients with 1-year minimum clinical and radiographic follow-up were evaluated (mean, 18.2 months; range, 12-27 months). Significant improvements were noted in the mean Disabilities of the Arm, Shoulder and Hand score (57.4 ± 16.5 vs. 29.4 ± 19.5, P < .001), mean Constant score (24.6 ± 10.2 vs. 60.4 ± 14.5, P < .001), mean American Shoulder and Elbow Surgeons score (32 ± 18.2 vs. 79 ± 15.6, P < .001), mean Simple Shoulder Test score (4.5 ± 2.6 vs. 9.3 ± 1.8, P < .001), mean Single Assessment Numeric Evaluation score (25.4 ± 13.7 vs. 72.2 ± 17.8, P < .001), mean visual analog scale pain score (6.2 ± 2.9 vs. 0.7 ± 1.3, P < .001), mean active forward flexion (53° ± 27° vs. 124° ± 23°, P < .001), and mean active abduction (42° ± 17° to 77° ± 15°, P < .001). Mean external rotation changed from 17° ± 19° to 32° ± 24° (P = .06). No radiographic evidence of component loosening, scapular notching, or hardware failure was observed at last follow-up in any patient., Conclusion: The preliminary results of rTSA using the VRS to manage severe glenoid bone deficiency are promising, but longer follow-up is necessary to determine the longevity of this implant., (Copyright © 2020 The Authors. Published by Elsevier Inc. All rights reserved.)

Background: Reverse shoulder arthroplasties have progressed in recent decades to become the most popular type of arthroplasty. Short stems with metaphyseal fixation have been developed to preserve bone stock and facilitate possible revision. Accurate positioning of these implants can be challenging using the superolateral approach., Objective: This study aimed to evaluate the clinical and radiologic results of reverse short-stem arthroplasties using a superolateral approach with a minimum of 2 years' follow-up., Methods: Between January 2015 and December 2016, a total of 76 patients underwent reverse shoulder arthroplasty surgery (79 shoulders) using a short uncemented humeral stem for shoulder arthritis with irreparable rotator cuff tear. Arthroplasties for post-traumatic osteoarthritis were excluded. Functional outcomes were assessed using Constant Score, American Shoulder and Elbow Surgeons Standardized Shoulder Assessment Form (ASES), visual analog scale (VAS), and range of motion. Radiographic analysis was used to evaluate component loosening, implant position, and implant filling ratio., Results: The mean age was 70.8 years. At a mean of 38.8-month follow-up, there were significant improvements in Constant score (44.2 to 87.9, P < .001), ASES score (36.2 to 84.3, P < .001), and VAS score (6.8 to 0.4, P < .001). Forward flexion improved from 89°to 131°(P < .001), and external rotation improved from 25° to 36°(P < .001). No evidence of periprosthetic loosening was visible. Mean varus of the humeral stem was 1°(±6°). The mean glenoidal inclination was 98°(±7°), which corresponds to a lower tilt of 8°. The average filling ratio was between 50% and 60% in both the metaphysis and the diaphysis., Conclusion: The clinical results obtained in this study were satisfying, with a significantly low complication rate. Hence, short-stem reverse shoulder arthroplasty using a superolateral approach, while taking particular care to protect the deltoid, remains our method of choice., (Copyright © 2019 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.)

Background: Biomechanical studies show that inlay glenoid components in total shoulder arthroplasty (TSA) can reduce edge loading and opposite-edge lift-off forces with humeral translation compared with onlay glenoids. However, clinical data for these implants are lacking. We report clinical outcomes and return to activities after anatomic TSA with an inlay glenoid component and a stemless ovoid humeral head in an active, young patient population., Methods: A retrospective review of TSA with an inlay glenoid component and an ovoid humeral head component was performed for 27 shoulders. Patients were evaluated with patient-reported outcome measures, range of motion, and radiographs. Return to occupational and sporting activity, complications, and reoperations were analyzed., Results: A total of 27 shoulders were available for minimum 2-year follow-up. Age averaged 52.1 years, and 92.6% of shoulders were in male patients. The preoperative Walch grade was A1 or A2 in 15 shoulders (55%), B1 in 8 (30%), and B2 in 4 (15%). Patients showed significant improvements in patient-reported outcome measures, active forward flexion, and external rotation (P < .001) with no reoperations. At an average of 3.7 months, the rate of return to work was 92.6%, with 76.0% of those patients returning to their preoperative occupational demand level. At an average of 9.1 months, 75% of patients who responded to our custom survey returned to sport, with 50% achieving the same level or a higher level of sporting activity. Annual postoperative radiographs revealed no inlay component loosening., Conclusion: Anatomic TSA with an inlay glenoid coupled with a stemless ovoid humeral head in an active population resulted in improved clinical outcomes, no reoperations or radiographic loosening, and a high rate of return to activity at shorter-term follow-up., (Copyright © 2019 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.)

We present a case of Nocardia farcinica after placement of reverse shoulder prosthesis in a 73-year-old woman. One month after surgery, the patient was admitted to the hospital with a spontaneous drainage of the wound and complaints of aggravating pain in the operated shoulder. There was no history of an immunosuppressive disease or therapy. After cultivation and empiric therapy with flucloxacillin, Nocardia farcinica was found and treated with a combination of intravenous amikacin and ceftriaxone. Eight days after drainage, a rinse and replacement of the polyethylene cup and glenosphere was executed. The treatment was proven to be successful whereas X-ray scans showed no complications nor any other consequences up until five years after therapy. To our knowledge, this is the first shoulder prosthetic Nocardia infection published in English literature. The aim of this report is to review/gather the knowledge about this particular infection and inform health care providers about this uncommon case.

Background: The aim of this study was to investigate the validity of implant sonication fluid cultures in the diagnosis of shoulder periprosthetic joint infection (PJI) compared with tissue culture., Methods: This was a retrospective case-control study analyzing all patients who underwent a revision surgery for any kind of suspected septic or aseptic event due to failed shoulder arthroplasty at our institution between July 2014 and December 2018. The diagnostic validity of implant sonication was analyzed on the basis of the last proposed definition criteria of the International Consensus Meeting and compared with standard tissue cultures., Results: Of the 72 patients, a total of 28 (38.9%) were classified as infected. Of the 28 infected patients, 20 (71.4%) had an identified organism by tissue cultures, and Cutibacterium acnes was the most commonly isolated pathogen. The sensitivities of sonicate fluid (≥50 CFU/mL) and periprosthetic tissue culture for the diagnosis of periprosthetic shoulder infection were 36% and 61% (P = .016), and the specificities were 97.7% and 100% (P > .99), respectively. If no cutoff value was used in sonication culture, the sensitivity increased to 75% whereas the specificity dropped to 82%. Although there was no significant difference in sensitivity between tissue culture and the no-cutoff sonication fluid culture (61% vs. 75%, P = .125), the specificity of tissue culture was significantly higher (100% vs. 82%, P = .01)., Conclusion: Tissue culture showed a higher sensitivity and specificity than implant sonication in the diagnosis of shoulder PJI and should remain the gold standard for microbiological diagnosis of shoulder PJI., (Copyright © 2019 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.)

Background: The purpose of this study was to evaluate the radiologic results of total shoulder arthroplasty using computerized three-dimensional (3D) templating in preoperative planning., Methods: Ten patients who underwent total shoulder arthroplasty using 3D templating preoperatively were enrolled in this study. A specialized computer program was used to reconstruct the 3D images of the shoulder from the computed tomographic images. The 3D images of various sizes of prostheses were used as the template in surgical planning of the shoulder arthroplasty. The size of the glenoid, humeral head, and stem measured in 3D templating were compared with those used in actual operation. Anatomical parameters, such as humeral head size, radius of curvature, and greater tuberosity to humeral head distance of the replaced shoulder, were measured and compared with those of the contralateral normal shoulder., Results: The agreement rates between the glenoid size, head size, head thickness, and stem size estimated preoperatively by 3D templating and those measured in operation were 100%, 100%, 100%, and 80%, respectively. The difference in humeral head size, radius of curvature, and greater tuberosity to humeral head distance between the replaced shoulder and contralateral shoulder was 1.31 mm, 0.87 mm, and 1.17 mm, respectively., Conclusions: In total shoulder arthroplasty, 3D templating seems to enable accurate prediction of sizes of the prostheses to be inserted and thus replication of normal anatomy., Competing Interests: CONFLICT OF INTEREST: No potential conflict of interest relevant to this article was reported., (Copyright © 2020 by The Korean Orthopaedic Association.)

Background: Assessment of glenoid bone defects is important to select the optimal glenoid component design during shoulder arthroplasty planning and implantation. This study presents a fully automated method to describe glenoid bone loss using 3-dimensional measurements without the need for a healthy contralateral reference scapula., Methods: The native shape of the glenoid is reconstructed by fitting a statistical shape model (SSM) of the scapula. The total vault loss percentage, local vault loss percentages, defect depth, defect area percentage, and subluxation distance and region are computed based on a comparison of the reconstructed and eroded glenoids. The method is evaluated by comparing its results with a contralateral bone-based reconstruction approach in a data set of 34 scapula and humerus pairs with unilateral glenoid bone defects., Results: The SSM-based defect measurements deviated from the contralateral bone-based measurements with mean absolute differences of 5.5% in the total vault loss percentage, 4.5% to 8.0% in the local vault loss percentages, 1.9 mm in the defect depth, 14.8% in the defect area percentage, and 1.6 mm in the subluxation distance. The SSM-based method was statistically equivalent to the contralateral bone-based method for all parameters except the defect area percentage., Conclusion: The presented method is able to automatically analyze glenoid bone defects using 3-dimensional measurements without the need for a healthy contralateral bone., (Copyright © 2019 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.)

Background: In vitro wear studies demonstrate decreased polyethylene wear with a ceramic compared with a metal humeral head. In this in vivo study, we analyzed prospectively collected 5-year data, comparing the outcomes of 2 types of humeral implants., Methods: Sixty-two anatomic total shoulder arthroplasties (TSAs) (59 patients) were performed using the same glenoid component and 2 types of modular humeral implants (metal-head long-stem prosthesis in group A vs. ceramic-head stemless prosthesis in group B). Radiographic analysis for proximal humeral osteolysis and glenoid component radiolucent lines was performed at an average of 5.5 years. Functional outcomes were prospectively evaluated according to the visual analog scale score for pain; satisfaction level; American Shoulder and Elbow Surgeons score; active elevation; Shoulder Pain and Disability Index score; and Disabilities of the Arm, Shoulder and Hand score., Results: There were 39 TSAs in group A (mean age, 68.1 years) and 23 TSAs in group B (mean age, 67 years). Clinical improvement was similar for both groups. Some proximal humeral osteolysis occurred in 56% of all TSAs. Group A showed increased osteolysis compared with group B (72% vs. 30%, P = .005). Glenoid radiolucent lines were far more frequent in group A, and group A showed a direct relationship between the extent of humeral osteolysis and the severity of glenoid radiolucent lines (P < .001)., Conclusion: The stemless ceramic-head replacements showed fewer glenoid radiolucent lines and less humeral osteolysis than the long-stem metal-head replacements. In the group with metal-head replacements, correlation was shown between glenoid radiolucent lines and humeral osteolysis., (Copyright © 2019 The Authors. Published by Elsevier Inc. All rights reserved.)