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The Trillat procedure, initially described by Albert Trillat, is historically one of the first techniques for addressing recurrent anterior shoulder instability, incorporating fascinating biomechanical mechanisms. After lowering, medializing, and fixing the coracoid process to the glenoid neck, the subcoracoid space is reduced, the subscapularis lowered, and its line of pull changed, accentuating the function of the subscapularis as a humeral head depressor centering the glenohumeral joint. Furthermore, the conjoint tendon creates a 'seatbelt' effect, preventing anteroinferior humeral head dislocation. Even though contemporary preferences lean towards arthroscopic Bankart repair with optional remplissage, bone augmentation, and the Latarjet procedure, enduring surgical indications remain valid for the Trillat procedure, which offers joint preservation and superior outcomes in two distinct scenarios: (i) older patients with massive irreparable cuff tears and anterior recurrent instability with an intact subscapularis tendon regardless of the extent of glenoid bone loss; (ii) younger patients with instability associated shoulder joint capsule hyperlaxity without concomitant injuries (glenoid bone loss, large Hill-Sachs lesion). Complications associated with the Trillat procedure include recurrent anterior instability, potential overtightening of the coracoid, leading to pain and a significant reduction in range of motion, risk of subcoracoid impingement, and restriction of external rotation by up to 10°, a limitation that is generally well-tolerated. The Trillat procedure may be an effective alternative technique for specific indications and should remain part of the surgical armamentarium for addressing anterior shoulder instability.

Background: The etiology of humeral posterior subluxation remains unknown, and it has been hypothesized that horizontal muscle imbalance could cause this condition. The objective of this study was to compare the ratio of anterior-to-posterior rotator cuff and deltoid muscle volume as a function of humeral subluxation and glenoid morphology when analyzed as a continuous variable in arthritic shoulders., Methods: In total, 333 computed tomography scans of shoulders (273 arthritic shoulders and 60 healthy controls) were included in this study and were segmented automatically. For each muscle, the volume of muscle fibers without intramuscular fat was measured. The ratio between the volume of the subscapularis and the volume of the infraspinatus plus teres minor (AP ratio) and the ratio between the anterior and posterior deltoids (AP deltoid ) were calculated. Statistical analyses were performed to determine whether a correlation could be found between these ratios and glenoid version, humeral subluxation, and/or glenoid type per the Walch classification., Results: Within the arthritic cohort, no statistically significant difference in the AP ratio was found between type A glenoids (1.09 ± 0.22) and type B glenoids (1.03 ± 0.16, P = .09), type D glenoids (1.12 ± 0.27, P = .77), or type C glenoids (1.10 ± 0.19, P > .999). No correlation was found between the AP ratio and glenoid version (ρ = -0.0360, P = .55) or humeral subluxation (ρ = 0.076, P = .21). The AP deltoid ratio of type A glenoids (0.48 ± 0.15) was significantly greater than that of type B glenoids (0.35 ± 0.16, P < .01) and type C glenoids (0.21 ± 0.10, P < .01) but was not significantly different from that of type D glenoids (0.64 ± 0.34, P > .999). When evaluating both healthy control and arthritic shoulders, moderate correlations were found between the AP deltoid ratio and both glenoid version (ρ = 0.55, P < .01) and humeral subluxation (ρ = -0.61, P < .01)., Conclusion: This in vitro study supports the use of software for fully automated 3-dimensional reconstruction of the 4 rotator cuff muscles and the deltoid. Compared with previous 2-dimensional computed tomography scan studies, our study did not find any correlation between the anteroposterior muscle volume ratio and glenoid parameters in arthritic shoulders. However, once deformity occurred, the observed AP deltoid ratio was lower with type B and C glenoids. These findings suggest that rotator cuff muscle imbalance may not be the precipitating etiology for the posterior humeral subluxation and secondary posterior glenoid erosion characteristic of Walch type B glenoids., (Copyright © 2024 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.)

Background: Both inlay and onlay humeral implants are available for reverse total shoulder arthroplasty (rTSA), but biomechanical data comparing these components remain limited. This study investigated the effects of inlay and onlay rTSA humeral components on shoulder biomechanics using a biorobotic shoulder simulator., Methods: Twenty fresh-frozen cadaveric shoulders were tested before and after rTSA with either an inlay or onlay humeral implant. Comparisons were performed between the most commonly implanted configurations for each implant (baseline) and with a modification to provide equivalent neck-shaft angles (NSAs) for the inlay and onlay configurations. Specimens underwent passive range-of-motion (ROM) assessment with the scapula held static, and scapular-plane abduction was performed, driven by previously collected human-subject scapulothoracic and glenohumeral kinematics. Passive ROM glenohumeral joint angles were compared using t tests, whereas muscle force and excursion data during scapular-plane elevation were evaluated with statistical parametric mapping and t tests., Results: Maximum passive elevation was reduced for the inlay vs. onlay humeral components, although both implants caused reduced passive elevation vs. the native joint. Inlay rTSA also demonstrated reduced passive internal rotation at rest and increased external rotation at 90° of humerothoracic elevation vs. the native joint. All preoperative planning estimates of ROM differed from experiments. Rotator cuff forces were elevated with an onlay vs. inlay humeral implant, but simulated muscle excursions did not differ between systems. Compared with the native joint, rotator cuff forces were increased for both inlay and onlay implants and deltoid forces were reduced for inlay implants. Muscle excursions were dramatically altered by rTSA vs. the native joint. Comparisons of inlay and onlay humeral implants with equivalent NSAs were consistent with the baseline comparisons., Conclusions: Rotator cuff forces required to perform scapular-plane abduction increase following rTSA using both inlay and onlay implants. Rotator cuff forces are lower with inlay implants compared with onlay implants, although inlay implants also result in reduced passive-elevation ROM. Deltoid forces are lower with inlay implants in comparison to the native joint but not with onlay implants. The differences between inlay and onlay components are largely unaffected by NSA, indicating that these differences are inherent to the inlay and onlay designs. In those patients with an intact rotator cuff, decreased rotator cuff forces to perform abduction with an inlay humeral implant compared with an onlay implant may promote improved long-term outcomes owing to reduced deltoid muscle fatigue when using an inlay implant., (Copyright © 2023 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.)

Background: Knowledge of premorbid glenoid parameters at the time of shoulder arthroplasty, such as inclination, version, joint line position, height, and width, can assist with implant selection, implant positioning, metal augment sizing, and/or bone graft dimensions. The objective of this study was to validate a scapular statistical shape model (SSM) in predicting patient-specific glenoid morphology in scapulae with clinically relevant glenoid erosion patterns., Methods: Computed tomography scans of 30 healthy scapulae were obtained and used as the control group. Each scapula was then virtually eroded to create 7 erosion patterns (Walch A1, A2, B2, B3, D, Favard E2, and E3). This resulted in 210 uniquely eroded glenoid models, forming the eroded glenoid group. A scapular SSM, created from a different database of 85 healthy scapulae, was then applied to each eroded scapula to predict the premorbid glenoid morphology. The premorbid glenoid inclination, version, height, width, radius of best-fit sphere, and glenoid joint line position were automatically calculated for each of the 210 eroded glenoids. The mean values for all outcome variables were compared across all erosion types between the healthy, eroded, and SSM-predicted groups using a 2-way repeated measures analysis of variance., Results: The SSM was able to predict the mean premorbid glenoid parameters of the eroded glenoids with a mean absolute difference of 3° ± 2° for inclination, 3° ± 2° for version, 2 ± 1 mm for glenoid height, 2 ± 1 mm for glenoid width, 5 ± 4 mm for radius of best-fit sphere, and 1 ± 1 mm for glenoid joint line. The mean SSM-predicted values for inclination, version, height, width, and radius were not significantly different than the control group (P > .05)., Discussion: An SSM has been developed that can reliably predict premorbid glenoid morphology and glenoid indices in patients with common glenoid erosion patterns. This technology can serve as a useful template to visually represent the premorbid healthy glenoid in patients with severe glenoid bony erosions. Knowledge of the premorbid glenoid preoperatively can assist with implant selection, positioning, and sizing., (Copyright © 2024 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.)

Background: Mixed reality may offer an alternative for computer-assisted navigation in shoulder arthroplasty. The purpose of this study was to determine the accuracy and precision of mixed-reality guidance for the placement of the glenoid axis pin in cadaver specimens. This step is essential for accurate glenoid placement in total shoulder arthroplasty., Methods: Fourteen cadaveric shoulders underwent simulated shoulder replacement surgery by 7 experienced shoulder surgeons. The surgeons exposed the cadavers through a deltopectoral approach and then used mixed-reality surgical navigation to insert a guide pin in a preplanned position and trajectory in the glenoid. The mixed-reality system used the Microsoft Hololens 2 headset, navigation software, dedicated instruments with fiducial marker cubes, and a securing pin. Computed tomography scans obtained before and after the procedure were used to plan the surgeries and determine the difference between the planned and executed values for the entry point, version, and inclination. One specimen had to be discarded from the analysis because the guide pin was removed accidentally before obtaining the postprocedure computed tomography scan., Results: Regarding the navigated entry point on the glenoid, the mean difference between planned and executed values was 1.7 ± 0.8 mm; this difference was 1.2 ± 0.6 mm in the superior-inferior direction and 0.9 ± 0.8 mm in the anterior-posterior direction. The maximum deviation from the entry point for all 13 specimens analyzed was 3.1 mm. Regarding version, the mean difference between planned and executed version values was 1.6° ± 1.2°, with a maximum deviation in version for all 13 specimens of 4.1°. Regarding inclination, the mean angular difference was 1.7° ± 1.5°, with a maximum deviation in inclination of 5°., Conclusions: The mixed-reality navigation system used in this study allowed surgeons to insert the glenoid guide pin on average within 2 mm from the planned entry point and within 2° of version and inclination. The navigated values did not exceed 3 mm or 5°, respectively, for any of the specimens analyzed. This approach may help surgeons more accurately place the definitive glenoid component., (Copyright © 2023 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.)

Background: Total shoulder arthroplasty (TSA) aims to reconstruct the premorbid anatomy of a pathologic shoulder. A healthy contralateral shoulder could be useful as a template in planning TSA. The symmetry between the left and right shoulders in healthy patients remains to be proved. The purpose of this study was to compare the 3-dimensional anatomy of the glenoid between sides in a healthy population., Methods: A multinational computed tomography scan database was retrospectively reviewed for all healthy bilateral shoulders in patients aged between 18 and 50 years. One hundred thirty pairs of healthy shoulder computed tomography scans were analyzed, and glenoid version, inclination, width, and height, as well as glenoid lateral offset and scapula lateral offset, were measured. All anatomic measures were computed with Blueprint, validated 3-dimensional planning software. The intraclass correlation coefficient was determined for each measure between left and right shoulders. The minimal detectable change (MDC) was calculated using the following formula: MDC=2×1.96×Standarderrorofmeasurement., Results: The comparison between 130 pairs of healthy scapulae showed statistically significant differences in absolute values between right and left glenoid version (-5.3° vs. -4.6°, P < .01), inclination (8.4° vs. 9.3°, P < .01), and width (25.6 mm vs. 25.4 mm, P < .01), as well as scapula offset (105.8 mm vs. 106.2 mm, P < .01). Glenoid height was comparable between right and left shoulders (33.3 mm vs. 33.3 mm, P = .9). The differences between the means were always inferior to the MDC regarding glenoid version, inclination, height, and width, as well as scapula offset. Very strong intraclass correlation coefficients between the left and right shoulders were found for all evaluated paired measures., Conclusion: Healthy contralateral scapulae are highly reliable to predict inclination, height, width, and scapula offset and are reliable to predict version of a given scapula. Paired right and left scapulae were not statistically symmetrical regarding mean glenoid version, inclination, and width, as well as scapula offset. Nevertheless, the reported differences were not higher than the MDC for this cohort, confirming that healthy contralateral shoulders can be a useful template in TSA preoperative planning., (Copyright © 2023 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.)

Purpose: Reverse shoulder arthroplasty (RSA) has shown improvement in clinical outcomes for various conditions, although some authors expressed concern about the restoration of active internal rotation (AIR). The current study assesses preoperative and intraoperative predictive factors of AIR in patients having a Grammont-style RSA with a minimum five year follow-up., Methods: We conducted a retrospective multicentric study, including patients operated on with a 155° Grammont-style RSA for cuff-related pathology or primary osteoarthritis with posterior subluxation or an associated cuff tear. Patients were clinically evaluated at a minimum of five year follow-up. Patients with previous surgery or those who had a tendon transfer with the RSA were excluded. Demographic parameters, BMI, preoperative notes, and operative reports were obtained from medical records. AIR was graded according to the constant score system from 0 to 10., Results: A total of 280 shoulders in 269 patients (mean age at surgery, 74.9 ± 5.9 years) met the inclusion criteria and were analyzed. The average follow-up was 8.1 years (range, 5-16 years). Overall, AIR increased from 4.2 (SD 2.5, range 0 to 10) preoperatively to 5.9 (SD 2.6, range 0 to 10) at final follow-up. At the last follow-up, AIR increased in 56% of cases, was unchanged in 26% and decreased in 18%. In 188 shoulders (67%), internal rotation was functional and allowed patients to reach the level of L3 or higher. Multivariable linear regression found the following preoperative clinical factors predictive of worse AIR after RSA: male gender (ß = -1.25 [-2.10; -0.40]; p = 0.0042) and higher values of BMI (ß = -0.085 [-0.17; -0.0065]; p = 0.048). Two surgical factors were associated with better AIR after RSA: glenoid lateralization with BIO-RSA technique (ß = 0.80 [0.043; 1.56]; p = 0.039) and subscapularis repair (ß = 1.16 [0.29; 2.02]; p = 0.0092)., Conclusions: With a mean of eight year follow-up (5 to 16 years), internal rotation was functional (≥ L3 level) in 67% of operated shoulders after Grammont-style RSA; however, two patients out of ten had decreased AIR after surgery. Male patients and those with higher BMIs had worse AIR, with glenoid lateralization (using the BIO-RSA technique) and subscapularis repair, as they are predictive of increased AIR after RSA., Level of Evidence: Case series, Level IV., (© 2023. The Author(s) under exclusive licence to SICOT aisbl.)

Introduction: The etiology of humeral posterior subluxation remains unknown, and it has been hypothesized that horizontal muscle imbalance could cause this condition. The objective of this study was to compare the ratio of anterior to posterior rotator cuff muscle and deltoid volumes as a function of humeral subluxation and glenoid morphology when analyzed as continuous variable in arthritic shoulders., Methods: Three hundred and thirty-three (273 arthritic and 60 healthy controls) CT scans of shoulders were included in this study and were segmented automatically. For each muscle, the volume of muscle fibers without intra-muscular fat was then measured. The ratio between the volume of the subscapularis and the volume of the infraspinatus + teres minor (AP ratio) and the ratio between the anterior and posterior deltoid (AP deltoid ) were calculated. Statistical analyses were performed to determine whether a correlation could be found between these ratios and glenoid version/ humeral subluxation/glenoid type in the Walch classification., Results: Within the arthritic cohort, no statistically significant difference was found between the AP ratio between A and type B glenoids (1.09 ± 0.22 versus 1.03 ± 0.16 p=0.09), between A and D type glenoids (1.09 ± 0.22 versus 1.12 ± 0.27, p=0.77) nor between the A and C type glenoids (1.09 ± 0.22 versus 1.10 ± 0.19, p=1). No correlation was found between AP ratio and glenoid version/humeral subluxation (rho =-0.0360, p=0.55; rho = 0.076; p=0.21). The AP deltoid ratio of type A glenoids was significantly greater than that of type B glenoids (0.48 ± 0.15 versus 0.35 ± 0.16, p< 0.01), and type C glenoids (0.48 ± 0.15 versus 0.21±0.10, p < 0.01) but not significantly different from the AP deltoid ratio of type D glenoids (0.48 ± 0.15 versus 0.64 ± 0.34, p=1). When evaluating both healthy control and arthritic shoulders, moderate correlations were found between AP deltoid ratio and glenoid version/humeral subluxation (rho=0.55, p<0.01; rho=-0.61, p<0.01)., Conclusion: As opposed to previous two-dimensional CT scan studies, we did not find any correlation between AP muscle volume ratio and glenoid parameters in arthritic shoulders. Therefore, rotator cuff muscle imbalance does not seem to be associated with posterior humeral subluxation leading to posterior glenoid erosion and subsequent retroversion characteristic of Walch B glenoids. However, our results could suggest that a larger posterior deltoid pulls the humerus posteriorly into posterior subluxation, but this requires further evaluation as the deltoid follows the humerus possibly leading to secondary asymmetry between the anterior and the posterior deltoid., (Copyright © 2023. Published by Elsevier Inc.)

Purpose: The purpose of the present study is to report the mid- and long-term clinical and radiologic outcomes of the arthroscopic Trillat for the treatment of recurrent anterior instability in patients with chronic massive irreparable rotator cuff tears (MIRCTs) and maintained active shoulder motion where reverse shoulder arthroplasty (RSA) is not indicated., Methods: Twenty-one consecutive patients (mean age 61 years) were identified and retrospectively reviewed. All patients had recurrent anterior dislocations and conserved active forward elevation and active external rotation. The MIRCTs included a retracted (stage 3) supraspinatus tear in 14%, a supra- and infraspinatus tear in 76.5%, and a 3-tendon tear in 14%. A closed-wedge osteotomy of the coracoid was performed, and the coracoid was fixed above the subscapularis with a cannulated screw (10 cases) or suture buttons (11 cases). We followed patients with x-rays and computed tomography scan at 6 months, along with Subjective Shoulder Value, visual analog scale, Walch, Constant, and Rowe scores. The mean clinical and radiographic follow-up was 58 months (24-145 months)., Results: Overall, 96% (20/21) of the patients had a stable and functional shoulder and were satisfied with the procedure; no patient lost active shoulder motion. The Subjective Shoulder Value increased from 44% (10%-75%) to 94% (80%-100%), P < .001. The Constant and Rowe scores improved from 60 (25-81) to 81 (66-96) and from 54 (35 to 65) to 92 (70-100), respectively (P < .001). Among the 13 patients practicing sports before surgery, 10 (77%) went back to sports. At last follow-up, only 1 patient was revised to RSA., Conclusions: The arthroscopic Trillat procedure is a valuable and durable option for the treatment of recurrent anterior dislocations in older patients with chronic MIRCTs and conserved active shoulder motion., Level of Evidence: Level IV, therapeutic case series., (Copyright © 2022. Published by Elsevier Inc.)

Purpose: The purpose of this study is to report the outcomes of the all-arthroscopic Trillat procedure, combined with capsular plication, for the treatment of recurrent anterior instability in young athletes with shoulder hyperlaxity (external rotation >90°)., Methods: We performed a retrospective evaluation of patients with recurrent anterior instability and shoulder hyperlaxity who underwent an arthroscopic Trillat between 2009 and 2019. Patients with concomitant rotator cuff lesions or voluntary or multidirectional instability were excluded. The osteotomized coracoid was fixed above the subscapularis with a cannulated screw or a suture button; a capsular plication was systematically associated. We followed patients with x-rays, computed tomography scans, and Subjective Shoulder Value, visual analog scale, Walch, Constant, and Rowe scores. Mean follow-up was 56 months (24-145)., Results: Twenty-eight consecutive patients (30 shoulders) with a mean age of 25 years were identified, and all met criteria. The main finding under arthroscopy was a "loose shoulder" with anteroinferior capsular redundancy and no or few (10%) labrum tears, glenoid erosion (13%), or Hill-Sachs lesions (10%). At last follow-up, 90% of the shoulders (27/30) were stable, and 79% (19/24) of the patients practicing sports returned to their preinjury activity level. The Walch-Duplay and Rowe scores improved from 54 (38-68) to 81 (4-100) and 55 (30-71) to 84 (45-100), respectively, P < .001., Conclusions: The arthroscopic Trillat is an effective procedure for the treatment of recurrent anterior instability in young athletes with shoulder hyperlaxity but no substantial humeral or glenoid bone loss, allowing return to overhead/contact sports., Level of Evidence: Level IV, retrospective study., (Copyright © 2022. Published by Elsevier Inc.)

Introduction: Radiographic stress shielding is a common finding in uncemented convertible short-stem shoulder arthroplasty (UCSSSA). The distal filling ratio (DFR) has been described as a predictor for the occurrence of stress shielding. A DFR > 70% was mentioned as a risk factor for the occurrence of stress shielding for some UCSSSA. However, measurements were only performed on conventional radiographs and no validation exists for 3D automated planning tools., Methods: DFR was manually measured on postoperative true ap radiographs of 76 shoulder arthroplasties using a standardized protocol and were compared to preoperative CT scans with an automated calculation of the DFR after virtual implantation of the stem., Results: The mean DFR measured on X-rays was 75.9% (SD = 8.7; 95% CI = 74-78) vs. 78.9% (SD = 9.1; 95% CI = 76.8-83) automatically measured on CT scans. This difference was significant (p < 0.001). In 7 out of 76 cases (9%) the difference between manual measurement on radiographs and computerized measurement on CT scans was > 10%., Conclusion: Manual measurement of the DFR is underestimated on conventional radiographs compared to automated calculation on CT scans be a mean of 3%. Therefore, automated measurement of the DFR on CT scans seems to be beneficial, especially in cases with osteopenic cortices. Manual measurement of the DFR on conventional ap radiographs in cases without CT scans, however, is still a viable alternative., Level of Evidence: Level IV, retrospective study., (© 2022. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Background: Glenoid bone loss is one of the main challenges in revision of failed shoulder arthroplasties. The concept of a hemi-reverse procedure is to implant a glenoid baseplate and glenosphere to protect the glenoid reconstruction to allow it to heal and to preserve the joint space for a potential second-stage humeral component implantation. The purpose of this study was to report the results of hemi-reverse procedures., Methods: Revision to a hemi-reverse procedure was performed in 15 patients: 8 with a failed anatomic total shoulder arthroplasty, 3 with a failed reverse shoulder arthroplasty, 3 with a failed humeral hemiarthroplasty, and 1 with placement of a cement spacer owing to sepsis after a total shoulder arthroplasty. After complete removal of the initial prosthesis, all patients underwent glenoid reconstruction with bone grafting and implantation of a reverse arthroplasty baseplate and glenosphere. A humeral implant was not placed in any case. The patients were prospectively followed up and underwent complete clinical and radiologic studies preoperatively and postoperatively at a minimum of 2 years after the surgical procedure., Results: Thirteen hemi-reverse implants and glenoid bone grafts healed (86%) and remained radiographically stable. One hemi-reverse construct migrated and became mechanically loose, which was attributed to absent fixation of the central post in the native glenoid bone. In 1 patient, an implant-related infection developed; irrigation and debridement were performed, in addition to revision to a resection arthroplasty. After documented radiographic healing of the hemi-reverse glenoid reconstruction, 5 patients underwent a second-stage revision to a reverse procedure with insertion of a humeral component at a median of 6 months (interquartile range [IQR], 6-8 months). In this group, the median follow-up period was 73 months (IQR, 45-153 months), the median Constant score was 48 (IQR, 41-56), median active forward elevation was 135° (IQR, 100°-150°), and the median Subjective Shoulder Value was 50% (IQR, 50%-60%). In the group of 9 patients with remaining hemi-reverse implants, the median follow-up period was 38 months (IQR, 29-60 months), the median Constant score was 41 (IQR, 38-46), median active forward elevation was 100° (IQR, 80°-100°), and the median Subjective Shoulder Value was 50% (IQR, 40%-60%)., Conclusion: The hemi-reverse procedure is an effective revision procedure to reconstruct a severely deficient glenoid. The hemi-reverse procedure may function as the definitive procedure, with satisfactory outcomes. Additionally, in patients who undergo the hemi-reverse procedure, second-stage revision to a total reverse procedure can be performed once imaging confirms bone graft and construct stability., (Copyright © 2022 Journal of Shoulder and Elbow Surgery Board of Trustees. All rights reserved.)

Background: Implant manufacturers typically offer several sizes of a humeral stem for shoulder arthroplasty so that time zero fixation can be achieved with the optimal size. Stem size can be templated preoperatively but is definitively determined intraoperatively. The purpose of this study was to determine if preoperatively acquired parameters, including patient demographics and imaging, could be used to reliably predict intraoperative humeral stem size., Methods: A cohort of 290 patients that underwent shoulder arthroplasty (116 anatomic and 174 reverse) was analyzed to create a regression formula to predict intraoperative stem size. The initial cohort was separated into train and test groups (randomly selected 80% and 20%, respectively). Patient demographics, anatomical measurements, and statistical shape model parameters determined from a preoperative shoulder arthroplasty planning software program were used for multilinear regression. The implant used for all cases was a short-stemmed metaphyseal-fit prosthesis., Results: Metaphyseal bone density, humeral statistical shape model parameters, and humeral intramedullary canal diameter were identified as highly predictive of intraoperative final humeral prosthesis size. On the train group, a coefficient of determination R 2 of 0.63 was obtained for the multilinear regression equation combining these parameters. When analyzing the cohort for the prediction of stem size in the test group, 95% were within plus or minus one size of that used during surgery., Conclusion: Preoperative criteria such as humeral geometry and proximal humeral bone density can be combined in a single multilinear equation to predict intraoperative humeral stem size within one size variation. Embedding the surgeon's decision-making process into an automated algorithm potentially allows this process to be applied across the surgical community. Predicting intraoperative decisions such as humeral stem size also has potential implications for the management of implant stocks for both manufacturers and health-care facilities., (© 2022 The Author(s).)

Background: Glenoid bone loss in anatomic total shoulder arthroplasty (aTSA) remains a controversial and challenging clinical problem. Previous studies have shown high rates of glenoid loosening for aTSA in shoulders with retroversion, posterior bone loss, and posterior humeral head subluxation. This study is the first to present minimum 2-year follow-up data of an all-polyethylene, biconvex augmented anatomic glenoid component for correction of glenoid retroversion and posterior humeral head subluxation., Methods: This study is a multicenter, retrospective review of prospectively collected data on consecutive patients from 7 global clinical sites. All patients underwent aTSA using the biconvex posterior augmented glenoid (PAG). Inclusion criteria were preoperative computed tomographic (CT) scan, minimum 2 years since surgery, preoperative and minimum 2-year postoperative range of motion examination, and patient-reported outcome measures (PROMs). Glenoid classification, glenoid retroversion, and posterior humeral head subluxation were measured from preoperative CT and radiography and postoperative radiography. Statistical comparisons between pre- and postoperative values were performed with a paired t test., Results: Eighty-six of 110 consecutive patients during the study period (78% follow-up) met the inclusion criteria and were included in our analysis. Mean follow-up was 35 ± 10 months, with a mean age of 68 ± 8 years (range 48-85). Range of motion statistically improved in all planes from pre- to postoperation. Mean visual analog scale score improved from 5.2 preoperation to 0.7 postoperation, Single Assessment Numeric Evaluation score from 43.2 to 89.5, Constant score from 41.8 to 76.9, and American Shoulder and Elbow Surgeons Standardized Shoulder Assessment Form score from 49.8 to 86.7 (all P < .0001). Mean glenoid retroversion improved from 19.3° to 7.4° (P < .0001). Posterior subluxation improved from 69.1% to 53.5% and posterior decentering improved from 5.8% to -3.0% (P < .0001). There was 1 patient with both a prosthetic joint infection and radiographic glenoid loosening that required revision. Seventy-nine of 86 patients had a Lazarus score of 0 (no radiolucency seen about peg or keel) at final follow-up., Conclusions: This study shows that at minimum 2-year follow-up, a posterior-augmented all-polyethylene glenoid can correct glenoid retroversion and posterior humeral head subluxation. Clinically, there was significant improvement in both range of motion and PROMs., (Copyright © 2022 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.)

Background: Early glenohumeral impingement leads to poor range of motion and notching in reverse shoulder arthroplasty. The aim was to find from planning software which implant configuration provides the best motions in reverse shoulder arthroplasty., Patients and Methods: Reverse shoulder arthroplasty planning (Glenosys) was made in 31 patients (12 men, 19 women, 76 ± 6 yo) and impingements were analyzed. Inlay (155°-inclined) and Onlay (145°-inclined) humeral designs were tested. Four configurations were tested for each shoulder: "INLAY": non-lateralized glenoid-inlay humerus, "BIO-INLAY": lateralized glenoid (BIO-RSA)-inlay humerus, "ONLAY": non-lateralized glenoid-onlay humerus, and "BIO-ONLAY": lateralized (BIO-RSA) glenoid-onlay humerus., Results: BIO-ONLAY and BIO-INLAY groups presented a significantly better result in all tested motion ( p  < 0.001 for all tests). BIO-ONLAY allowed a significantly better external rotation, extension and adduction than BIO-INLAY with decreased impingements with the pilar. BIO-INLAY presented a significantly better abduction. In abduction, an abutment of the greater tuberosity against the acromion was associated with a lower range of motion ( p  < 0.0001) and did not depend on the lateralization., Conclusion: Glenoid lateralization delays the glenohumeral impingement in reverse shoulder arthroplasty and gives the best rotations, adduction and extension when associated with neutral inclination and humeral 145° inclination. Greater tuberosity abutment has to be avoided in abduction and the Inlay design provides the best abduction., Competing Interests: Declaration of Conflicting Interests: The author(s) declared the following potential conflicts of interest with respect to the research, authorship, and/or publication of this article: Marc-Olivier Gauci, Julien Berhouet, Adrien Jacquot, Gilles Walch, and Pascal Boileau are consultants for Wright-Medical—Tornier Inc and Imascap and did not receive any financial payments or other benefits from any commercial entity related to the subject of this article. Jean Chaoui is an employee of Wright Medical—Tornier Inc and Imascap., (© 2021 The British Elbow & Shoulder Society.)

Background: Recurrent anterior glenohumeral instability caused by a humeral avulsion of the glenohumeral ligament (HAGL) lesion has been studied, but very limited long-term evidence is available., Purpose: To retrospectively review patients with a HAGL lesion who underwent an open Latarjet procedure for recurrent anterior shoulder instability., Study Design: Case series; Level of evidence, 4., Methods: A total of 16 patients with complete clinical and radiological data were available for a review. Clinical outcomes were assessed by range of motion, apprehension testing, the visual analog scale for pain, the Walch-Duplay score, the Rowe score, the Constant-Murley score, the Subjective Shoulder Value, and return to sports. Radiographs were reviewed for osteoarthritis and complications., Results: The median age of patients at the time of surgery was 28 years (range, 18-42 years). All patients were male with no hyperlaxity. The median follow-up time was 10 years (range, 2.8-15 years). Postoperative range of motion showed recovered forward elevation (median, 175°), external rotation (median, 62°), and internal rotation (median, 9 points). Overall, 87% returned to sports, with 68% to the same level and 93% satisfied or very satisfied. Median clinical outcomes were the following: visual analog scale score, 1 (range, 0-2); Walch-Duplay score, 86 (range, 75-100); Rowe score, 95 (range, 90-100); Constant-Murley score, 77 (range, 74-79); and Subjective Shoulder Value, 88% (range, 80%-95%). There were no recurrent dislocations or subluxations. One patient described mild long-term pain, and 1 patient had persistent stiffness. Other complications included 12% with subjective apprehension, 1 patient with a wound infection, and another patient with delayed bone graft union. Additionally, 56% of cases had mild postoperative arthritis at the final follow-up. There were no reoperations., Conclusion: The open Latarjet procedure provided good outcomes with acceptable complication rates in the long term for patients with HAGL lesions. It is an effective treatment option and a safe alternative to arthroscopic or open HAGL repair.

Background: In vitro data demonstrate the potential benefits of the pyrocarbon as a bearing material against cartilage or bone. And pyrocarbon-free interposition arthroplasty has been used with positive outcomes for over 10 years for hand and wrist joint replacements. This study reports the midterm results of a Pyrocarbon Interposition Shoulder Arthroplasty (PISA) in primary and secondary glenohumeral osteoarthritis and in avascular osteonecrosis., Methods: This prospective noncontrolled, multicenter study included 67 consecutive patients who underwent PISA in France and Sweden., Results: A cohort of 48 patients, aged 50 ± 12 years, was available for clinical assessment at a mean follow-up of 67.6 ± 9.3 months. A favorable change was reported with a mean absolute Constant score improvement of 32 ± 20 points. The highest Constant score improvement was observed in patients with avascular osteonecrosis (42 ± 18 points; P  ≤ .0001). Between the earliest and the latest follow-up, radiographic analyses revealed only 2 major glenoid erosions and 4 tuberosity thinnings and thus that 86.4% of 44 shoulders remained stable with no or minor radiologic evolutions. The survival rate was 84 % at 65 months of follow-up considering all causes of revision., Conclusion: The radiographic findings seem to confirm the interest of pyrocarbon in preserving bony surfaces. But the risk of tuberosity thinning suggests considering the use of PISA with caution in most degenerative glenohumeral joint pathologies, although the midterm outcomes highlight PISA as a suitable solution for patients presenting with posttraumatic osteonecrosis without malunion of the tuberosities and with an intact rotator cuff., (© 2022 Published by Elsevier Inc. on behalf of American Shoulder and Elbow Surgeons.)

Background. The indications for reverse shoulder arthroplasty (RSA) have been widely expanded, but only a few studies report the long-term survival of these implants. Our objective was to report the long-term survivorship of a large series of RSAs implanted for different etiologies. Methods. A retrospective multicenter study including all the RSAs was performed in six shoulder-specialized centers with at least 2 years of follow up. We reviewed 1611 RSAs, operated between 1993 and 2010, including 497 cuff-tear arthropathies (CTA), 239 revision RSAs, 188 massive cuff tears (MCT), 185 fracture sequelae (FS), 183 failed previous cuff repairs (FCR), and 142 primary osteoarthritis (POA). The mean follow-up was 5.6 ± 3.9 years (range 2−20). Results. Overall, 266 RSAs (16.5%) had at least one complication leading to 64 reoperations (4.0%) and 110 revision surgeries (6.8%). The most frequent complications were infection (3.8%), instability (2.8%), and humerus-related complications (2.8%). At 10 years, the survival without revision surgery was 91.0% in primary RSAs and 80.9% in revision RSAs for failed arthroplasty (p < 0.001). In the primary RSA group, MCT and FCR led to 10-year survivals for over 95% but fracture sequelae and tumors had the lowest 10-year survivals (83.9% and 53.1%). Younger patients had a lower 10-year survival. In revision RSAs, male patients had a significantly lower survival than females (72.3% vs. 84.5% at 10 years, p = 0.020). Discussion. Primary RSA for cuff-deficient shoulders or POA leads to a high 10-year survival, but revision RSA or primary RSA for FS and tumors are at high-risk for revision. Surgeons should be aware of high rates of complications and lower survival rates of RSA in younger patients, in males, and in RSAs for revision surgery.

Introduction: In the context of reverse shoulder arthroplasty, some parameters of glenoid baseplate placement follow established golden rules, while other parameters still have no consensus. The assessment of glenoid wear in the future location of the glenoid baseplate varies among surgeons. The objective of this study was to analyze the inter-observer reproducibility of glenoid baseplate 3D positioning during virtual pre-operative planning., Method: Four shoulder surgeons planned the glenoid baseplate position of a reverse arthroplasty in the CT scans of 30 degenerative shoulders. The position of the glenoid guide pin entry point and the glenoid baseplate center was compared between surgeons. The baseplate's version and inclination were also analyzed., Results: The 3D positioning of the pin entry point was achieved within ± 4 mm for nearly 100% of the shoulders. The superoinferior, anteroposterior and mediolateral positions of the baseplate center were achieved within ± 2 mm for 77.2%, 67.8% and 39.4% of the plans, respectively. The 3D orientation of the glenoid baseplate within ± 10° was inconsistent between the four surgeons (weak agreement, K=0.31, p=0.17)., Discussion: The placement of the glenoid guide pin was very consistent between surgeons. Conversely, there was little agreement on the lateralization, version and inclination criteria for positioning the glenoid baseplate between surgeons. These parameters need to be studied further in clinical practice to establish golden rules. Three-dimensional information from pre-operative planning is beneficial for assessing the glenoid deformity and for limiting its impact on the baseplate position achieved by different surgeons., Level of Evidence: III. Case control study., (Copyright © 2021. Published by Elsevier Masson SAS.)

Introduction: The arm change position (ACP) is a new parameter for evaluating the humerus' 3D displacement following reverse shoulder arthroplasty (RSA) during 3D pre operative planning. The purpose of this study was to analyze the relationship between ACP variations after RSA and simulated passive joint mobility. The assumption is that the ACP will to help optimize the passive joint mobility of a RSA implant., Methods: In 30 degenerative shoulders, four shoulder surgeons planned a RSA with virtual motion analysis. After this analysis, each plan was revised to optimize the range of motion. Relationships between the differences in movement amplitude and the differences in ACP were evaluated., Results: Arm lengthening and humerus lateralization were significantly associated with better joint mobility in all three planes (frontal, sagittal and axial). They were equally important for improving external rotation, extension, flexion and adduction. Anterior displacement of the humerus improved both internal and external rotation., Discussion: The ACP is a useful preoperative planning parameter for RSA. It could help with selecting the best implant combination, as well as determining their position, in order to optimize the simulated passive mobility relative to humerus displacement after RSA. To validate the value of the ACP in clinical practice, a prospective study is needed in which the postoperative joint mobility is measured in vivo as a function of the ACP., Level of Evidence: III, case control study., (Copyright © 2022 Elsevier Masson SAS. All rights reserved.)

Introduction: It has been well established that the subscapularis is divided in two different parts with a tendinous insertion at its superior two-thirds and a muscular attachment on its inferior third. The objective of this cadaveric study was to follow the muscular insertion of the subscapularis medially in order to determine the origin of this inferior muscle insertion and whether a subscapularis minor can be individualized MATERIALS AND METHODS: Twenty-six shoulders from thirteen fresh-frozen cadaveric specimens (5 males and 8 females; mean age, 74.4 years) were dissected in our anatomy lab. The humeral insertion of the subscapularis was then analyzed, and the inferior muscular part of the insertion was identified. The muscle fibers were followed medially until their scapular origin which was recorded as line drawings and photographs. We measured the dimensions of both the humeral insertion and of the scapular origin of the fibers going to the muscular portion., Results: In all cases, the fibres going to the tendinous portion and those going to the muscular portion of the insertion had a different orientation. The fibres going to the muscular portion of the humeral insertion did not originate from the subscapularis fossa but on the glenoid neck and in a depression at the infero-lateral part of the scapular pillar. The mean length of the superior tendinous portion of the humeral insertion was 3.42 cm (± 0.43 cm); the mean length of the inferior muscular portion of the humeral insertion was 1.88 cm (± 0.80 cm). The mean length of the scapular origin in the depression at the infero-lateral part of the scapular pillar of the fibres going to the muscular portion of the humeral insertion was 3.7 cm (± 0.17 cm)., Conclusion: The fibres of the subscapularis do not all originate from the subscapularis fossa. An additional origin exists at the inferior part of the glenoid neck and in a depression at the infero-lateral part of the scapular pillar. The fibers which originate at this location all insert on the humerus at the muscular portion of the subscapularis humeral insertion. This portion however does not seem to correspond to the so-called subscapularis minor which has been previously described., (© 2021. The Author(s) under exclusive licence to SICOT aisbl.)

Background: Various implant designs have been proposed to increase active range of motion (ROM) and avoid notching in patients treated by reverse total shoulder arthroplasty (RSA). The purpose of this study was to investigate the efficacy and safety of an onlay prosthesis design combining a 135° humeral neck-shaft angle with the glenoid component lateralized and inferiorized., Methods: A retrospective descriptive study was conducted of the clinical and radiological outcomes at the final follow-up (≥24 months) of all RSAs performed by the same surgeon between September 2015 and December 2016 in the study center. At the last follow-up, patients were clinically assessed for ROM, Constant score, and subjective shoulder value and radiologically for scapular notching and glenoid radiolucent lines. Patients were followed up radiographically at 1 month and clinically at between 6 and 12 months (midterm) and again at between 24 and 48 months (final follow-up). Scapular notching was graded as per the Sirveaux classification at the last follow-up on anterior-posterior radiographs., Results: Seventy-nine RSAs were included with a mean follow-up time of 31 months. The mean Constant score at the final follow-up was 42 points higher than before surgery (69 vs. 27, P  < .001). There were also significant postoperative improvements in ROM (active anterior elevation, active external rotation, and active internal rotation). The final means for motions were 133° for active anterior elevation, 32° active external rotation, and level 7 for active internal rotation. The overall notching rate was 3% (2/67), and there were no cases of severe notching. Radiolucent lines were observed in 8 of 70 prostheses (11.5%) around the peg, and they were observed in 9 prostheses (13%) around the screws. Among the 79 RSAs included, there were 11 complications (13.9%) (two infections, two fractures, four cases of glenoid component loosening, and three cases of instability), 2 reoperations, and 4 prosthesis revisions., Conclusion: This study shows that an RSA design with a 135° humeral neck-shaft angle and an inferiorized and lateralized glenoid component is associated with significant improvements in active ROM, especially in rotation, and a low notching rate. However, rates of 3.8% for dislocation and 5% for glenoid loosening are certainly a concern at such a short follow-up of two years. Future studies with a larger population are needed to confirm these rates., (© 2022 The Author(s).)

Background: Rotator cuff fatty infiltration (FI) is one of the most important parameters to predict the outcome of certain shoulder conditions. The primary objective of this study was to define a new computed tomography (CT)-based quantitative 3-dimensional (3D) measure of muscle loss (3DML) based on the rationale of the 2-dimensional (2D) qualitative Goutallier score. The secondary objective of this study was to compare this new measurement method to traditional 2D qualitative assessment of FI according to Goutallier et al and to a 3D quantitative measurement of fatty infiltration (3DFI)., Materials and Methods: 102 CT scans from healthy shoulders (46) and shoulders with cuff tear arthropathy (21), irreparable rotator cuff tears (18), and primary osteoarthritis (17) were analyzed by 3 experienced shoulder surgeons for subjective grading of fatty infiltration according to Goutallier, and their rotator cuff muscles were manually segmented. Quantitative 3D measurements of fatty infiltration (3DFI) were completed. The volume of muscle fibers without intramuscular fat was then calculated for each rotator cuff muscle and normalized to the patient's scapular volume to account for the effect of body size (NV fibers ). 3D muscle mass (3DMM) was calculated by dividing the NV fibers value of a given muscle by the mean expected volume in healthy shoulders. 3D muscle loss (3DML) was defined as 1 - (3DMM). The correlation between Goutallier grading, 3DFI, and 3DML was compared using a Spearman rank correlation., Results: Interobserver reliability for the traditional 2D Goutallier grading was moderate for the infraspinatus (ISP, 0.42) and fair for the supraspinatus (SSP, 0.38), subscapularis (SSC, 0.27) and teres minor (TM, 0.27). 2D Goutallier grading was found to be significantly and highly correlated with 3DFI (SSP, 0.79; ISP, 0.83; SSC, 0.69; TM, 0.45) and 3DML (SSP, 0.87; ISP, 0.85; SSC, 0.69; TM, 0.46) for all 4 rotator cuff muscles (P < .0001). This correlation was significantly higher for 3DML than for the 3DFI for SSP only (P = .01). The mean values of 3DFI and 3DML were 0.9% and 5.3% for Goutallier 0, 2.9% and 25.6% for Goutallier 1, 11.4% and 49.5% for Goutallier 2, 20.7% and 59.7% for Goutallier 3, and 29.3% and 70.2% for Goutallier 4, respectively., Conclusion: The Goutallier score has been helping surgeons by using 2D CT scan slices. However, this grading is associated with suboptimal interobserver agreement. The new measures we propose provide a more consistent assessment that correlates well with Goutallier's principles. As 3DML measurements incorporate atrophy and fatty infiltration, they could become a very reliable index for assessing shoulder muscle function. Future algorithms capable of automatically calculating the 3DML of the cuff could help in the decision process for cuff repair and the choice of anatomic or reverse shoulder arthroplasty., (Copyright © 2021 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.)

Backgroud: The 155° Grammont reverse shoulder replacement has a long track record of success, but also a high radiographic notching rate. The increased distance between the scapular pillar and the humeral component theoretically decreases postoperative notching. The glenoid component can be shifted inferiorly relative to the glenoid; however, there also is some concern that shifting the glenoid component too far inferiorly (inferior glenoid component overhang > 3.5 mm) may compromise long-term stability of the glenoid component. This study was conducted to determine if clinical outcomes, scapular notching, and complications vary with more inferior placement of the glenoid component., Methods: A retrospective analysis of prospectively collected data was performed in order to compare radiographic outcomes (notching rate and signs of glenoid loosening or component disassembly) and clinical outcomes (range of motion, Constant score, subjective shoulder value, and complication rate) of all patients who underwent reverse shoulder replacement with the glenosphere positioned either flush with the inferior rim of the glenoid (flush group) or with at least 3.5 mm of inferior overhang (overhang group) at a minimum follow-up of 60 months. Ninety-seven patients ultimately met the inclusion criteria, with 41 patients with flush glenoid component and 56 patients with at least 3.5 mm of inferior overhang., Results: Average follow-up was 97.8 months. The overhang group had a lower rate of radiographic notching (37% vs. 82.5%, p < 0.05), better clinical outcomes (improvement in Constant score: +40 vs. +32, p = 0.036), and higher subjective shoulder value (79 vs. 69, p = 0.026) than the flush group. No difference in complications between groups was found., Conclusions: In this study, at least 3.5 mm of inferior glenosphere overhang relative to the inferior rim of the glenoid was associated with the lower notching rate without negative effect on the clinical outcomes in 155° Grammont-style reverse shoulder replacement. Therefore, no increase in complications should be expected when using this surgical technique., Competing Interests: CONFLICT OF INTEREST: No potential conflict of interest relevant to this article was reported., (Copyright © 2021 by The Korean Orthopaedic Association.)

Indications for Reverse Shoulder Arthroplasty (RSA) have been extended over the last 25 years, and RSA has become the most frequently implanted shoulder arthroplasty worldwide. The initial Grammont design with medialization of the joint center of rotation (JCOR), placement of the JCOR at the bone-implant interface, distalization and semi-constrained configuration has been associated with drawbacks such as reduced rotation and range of motion (ROM), notching, instability and loss of shoulder contour. This review summarizes new strategies to overcome these drawbacks and analyzes the use of glenoid-sided, humeral-sided or global bipolar lateralization, which are applied differently by surgeons and current implant manufacturers. Advantages and drawbacks are discussed. There is evidence that lateralization addresses the initial drawbacks of the Grammont design, improving stability, rates of notching, ROM and shoulder contour, but the ideal extent of lateralization of the glenoid and humerus remains unclear, as well as the maximal acceptable joint reaction force after reduction. Overstuffing and spine of scapula fractures are potential risks. CT-based 3D planning as well as artificial intelligence will help surgeons with planning and execution of appropriate lateralization in RSA. Long-term follow-up of lateralization with new implant designs and implantation strategies is needed.

Background: Despite its potential biomechanical advantages, reverse shoulder arthroplasty (RSA) is still considered to be particularly high risk in rheumatoid patients who are osteoporotic and immunodeficient. Our purpose was to report prosthesis survival, complications, and outcomes of RSA in patients with rheumatoid arthritis (RA) at minimum 5-year follow-up., Methods: We conducted a retrospective multicenter study including 65 consecutive primary RSAs performed in 59 patients with RA between 1991 and 2010. We excluded rheumatoid patients with previous failed anatomic shoulder arthroplasty. Age at surgery averaged 69 years (range, 46-86 years). A structural bone grafting was performed in 18 cases (45%), using the humeral head in 15 cases (BIO-RSA technique), the iliac crest in 2 cases (Norris technique), and an allograft in 1 case. The mean follow-up was 92 months (range, 60-147 months) or until revision surgery., Results: Revision-free survivorship, using Kaplan-Meier curves, was 96% at 7 years. Two patients had revision surgeries for infections, with associated glenoid loosening in 1 case. No humeral loosening was recorded. The mean adjusted Constant score improved from 36% ± 23% preoperatively to 90% ± 26% postoperatively, and mean Subjective Shoulder Value improved from 21% ± 13% to 85% ± 12%, respectively (P < .001). Active anterior elevation increased from 65° ± 43° to 132° ± 27°, active external rotation increased from 10° ± 26° to 22° ± 27°, and internal rotation improved from buttocks to waist (P < .001). Stable fixation of the baseplate was achieved in all cases (including the 6 patients with end-stage RA), and we did not observe bone graft nonunion or resorption. Preoperative radiologic pattern (centered, ascending, or destructive), presence of acromial fractures or tilt (4 cases, 10%), and scapular notching (55%) on final radiographs were not found to influence outcomes or complication rate. Patients with absent/atrophied teres minor had lower functional results. Overall, 95% of the patients were satisfied with the procedure., Conclusion: RSA is a safe and effective procedure for the treatment of RA patients, with a low risk of complications and low rate of revision, regardless of the radiologic presentation and stage of the disease. Rheumatoid patients undergoing primary RSA, with or without glenoid bone grafting, can expect a revision-free survival rate of 96% at 7-year follow-up. RSA offers the benefit of solving 2 key problems encountered in rheumatoid shoulders: glenoid bone destruction and rotator cuff deficiency., (Copyright © 2021 The Authors. Published by Elsevier Inc. All rights reserved.)

Background: An assessment of the pathoanatomic parameters of the arthritic glenohumeral joint (GHJ) has the potential to identify discriminating metrics to differentiate glenoid types in shoulders with primary glenohumeral osteoarthritis (PGHOA). The aim was to identify the morphometric differences and threshold values between glenoid types including normal and arthritic glenoids with the various types in the Walch classification. We hypothesized that there would be clear morphometric discriminators between the various glenoid types and that specific numeric threshold values would allow identification of each glenoid type., Methods: The computed tomography scans of 707 shoulders were analyzed: 585 obtained from shoulders with PGHOA and 122 from shoulders without glenohumeral pathology. Glenoid morphology was classified according to the Walch classification. All computed tomography scans were imported in a dedicated automatic 3D-software program that referenced measurements to the scapular body plane. Glenoid and humeral modeling was performed using the best-fit sphere method, and the root-mean-square error was calculated. The direction and orientation of the glenoid and humerus described glenohumeral relationships., Results: Among shoulders with PGHOA, 90% of the glenoids and 85% of the humeral heads were directed posteriorly in reference to the scapular body plane. Several discriminatory pathoanatomic parameters were identified: GHJ narrowing < 3 mm was a discriminatory metric for type A glenoids. Posterior humeral subluxation > 70% discriminated type B1 from normal GHJs. The root-mean-square error was a discriminatory metric to distinguish type B2 from type A, type B3, and normal GHJs. Type B3 glenoids differed from type A2 by greater retroversion (>13°) and subluxation (>71%). The type C glenoid retroversion inferior limit was 21°, whereas normal glenoids never presented with retroversion > 16°., Conclusion: Pathoanatomic metrics with the identified threshold values can be used to discriminate glenoid types in shoulders with PGHOA., (Copyright © 2021 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.)

Background: The purpose of this study was to develop novel three-dimensional (3D) measures of bone density from computed tomography (CT) scans and to compare them with validated two-dimensional (2D) radiographic assessments of bone density. Patient demographic data were also analyzed to see if there were any predictors of bone density (age, sex, etiology)., Methods: The study group consisted of 290 consecutive patients undergoing primary shoulder arthroplasty surgery (total anatomic, reverse, and hemiarthroplasty). All underwent preoperative CT imaging. Three 3D CT measurements (metaphysis cancellous, metaphysis cortical, and proximal diaphysis) were developed and automated into software. The developed 3D measurements were compared with validated 2D measures (Tingart and Gianotti Index). Patient demographic data were correlated with these measurements. The difference between the size of the final sounder and of the final stem was calculated as Delta., Results: There was moderately strong correlation between Tingart and Gianotti measures (0.674, P  < .001), as well as between 3D metaphysis cancellous measurements and Tingart (0.645, P  < .001). Decreased bone density was highly correlated with female sex. Tingart (area under the curve [AUC]: 0.87, 95% confidence interval [CI]: 0.82-0.91) and 3D metaphysis cancellous (AUC: 0.78, 95% CI: 0.72-0.84) had the highest correlation. These were significantly more than other measures of bone density ( P  < .01). Decreased bone density measured with Tingart also had moderate correlation with advanced age (AUC: 0.67, 95% CI: 0.6-0.73), but less so for etiology (AUC: 0.62, 95% CI: 0.55-0.69). The 3D metaphysis cancellous measure had lower correlation with age (AUC: 0.59, 95% CI: 0.52-0.66) and etiology (AUC: 0.59, 95% CI: 0.52-0.65). The highest correlation with Delta (the difference between the final sounder and the stem size) was with the 3D metaphysis cancellous measure (AUC: 0.67, 95% CI: 0.59-0.73), followed by Tingart (AUC: 0.647, 95% CI: 0.57-0.671). A multiple regression model to predict Delta demonstrated the stronger prediction using 3D metaphysis cancellous (analysis of variance F-ratio of 42.6, P  < .001) than Tingart (35.9, P  < .001)., Conclusion: This study demonstrates that automated measures of bone density can be obtained from 3D CT scans. Of the three novel 3D measurements of bone density, the humeral metaphysis cancellous measurement was most correlated to the known 2D measures and most correlated to the intraoperative assessment of bone density (delta)., (© 2021 The Author(s).)

Background: The use of an eccentric glenosphere (EG) has been proposed as a way to prevent scapular notching in reverse shoulder arthroplasty (RSA). The purpose of this study was to investigate whether the use of an EG decreases scapular notching compared with matched standard concentric glenosphere (CG) controls., Methods: A retrospective analysis was performed. This study included 49 RSAs with an EG and 49 paired RSAs with a CG with a minimum 60 months of both clinical and radiographic follow-up. Clinical and radiologic outcomes of the EG and CG groups were compared at inclusion and at the last follow-up using the paired Student t test for quantitative data and the χ 2 test for qualitative data. Scapular notching was graded according to the Sirveaux classification. Statistical significance was set at P < .05., Results: Notching was observed 2.7 times (95% confidence interval, 1.0-6.8 times) more often in the CG group (P = .037). The difference in notching severity between the groups was not statistically relevant; however, there was a trend toward more severe notching in the CG group (P = .059). Compared with a CG, an EG did not increase the percentage of radiolucent lines around the screws (3% vs. 1.5%, P = .62), around the post (3% vs. 1.5%, P = .62), or below the baseplate (15% vs. 7.5%, P = .18)., Conclusion: EGs are associated with less notching than CGs. This finding confirms that RSA with an EG is an effective procedure without specific complications at a minimum follow-up of 5 years., (Copyright © 2020 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.)

Background: Total shoulder arthroplasty (TSA) and hemiarthroplasty (HA) have shown good clinical outcomes in primary avascular necrosis of the humeral head (PANHH) both in short and long terms. The purpose of this study was to assess the complications, the clinical and radiological outcomes of shoulder arthroplasty in young patients with PANHH., Methods: One hundred and twenty-seven patients aged under 60 years old and suffering from PANHH were operated with arthroplasty. Patients were assessed clinically and radiographically before surgery with a minimum of 2 years of follow up (FU)., Results: HA was performed on 108 patients (85%). Two patients were revised for painful glenoid wear after 2 and 4 years. TSA was performed on 19 patients (15%). Five TSA had to be revised for glenoid loosening ( n = 4) or instability ( n = 1). Revision rate was 26% with TSA and 2% with HA. There were no significant differences between HA and TSA in terms of clinical outcomes., Conclusions: With a mean FU of 8 years, HA and TSA improved clinical outcomes of patients with PANHH. HA revisions for painful glenoid wear were rare (2%). The revision rate was excessively high with TSA (26%).

Aims: The aim of this study was to describe a quantitative 3D CT method to measure rotator cuff muscle volume, atrophy, and balance in healthy controls and in three pathological shoulder cohorts., Methods: In all, 102 CT scans were included in the analysis: 46 healthy, 21 cuff tear arthropathy (CTA), 18 irreparable rotator cuff tear (IRCT), and 17 primary osteoarthritis (OA). The four rotator cuff muscles were manually segmented and their volume, including intramuscular fat, was calculated. The normalized volume (NV) of each muscle was calculated by dividing muscle volume to the patient's scapular bone volume. Muscle volume and percentage of muscle atrophy were compared between muscles and between cohorts., Results: Rotator cuff muscle volume was significantly decreased in patients with OA, CTA, and IRCT compared to healthy patients (p < 0.0001). Atrophy was comparable for all muscles between CTA, IRCT, and OA patients, except for the supraspinatus, which was significantly more atrophied in CTA and IRCT (p = 0.002). In healthy shoulders, the anterior cuff represented 45% of the entire cuff, while the posterior cuff represented 40%. A similar partition between anterior and posterior cuff was also found in both CTA and IRCT patients. However, in OA patients, the relative volume of the anterior (42%) and posterior cuff (45%) were similar., Conclusion: This study shows that rotator cuff muscle volume is significantly decreased in patients with OA, CTA, or IRCT compared to healthy patients, but that only minimal differences can be observed between the different pathological groups. This suggests that the influence of rotator cuff muscle volume and atrophy (including intramuscular fat) as an independent factor of outcome may be overestimated. Cite this article: Bone Jt Open  2021;2(7):552-561.

Purpose: To establish an international expert consensus, using the modified Delphi technique, on the evaluation and management of glenohumeral instability with associated bone loss., Methods: A working group of 6 individuals generated a list of statements related to history and physical examination, imaging and specialized diagnostic tests, bone loss quantification and classification, treatment outcomes and complications, and rehabilitation for the management of glenohumeral instability associated with bone loss to form the basis of an initial survey for rating by a group of experts. The expert group (composed of 22 high-volume glenohumeral instability experts) was surveyed on 3 occasions to establish a consensus on the statements. Items with over 70% agreement and less than 10% disagreement achieved consensus., Results: After a total of 3 rounds, 31 statements achieved consensus. Eighty-six percent of the experts agreed that a history of multiple dislocations and failed soft-tissue surgery should raise suspicion about the possibility of an associated bone deficit. Ninety-five percent of the experts agreed that 3-dimensional (3D) computed tomography (CT) is the most accurate diagnostic method to evaluate and quantify bone loss. Eighty-six percent of the experts agreed that any of the available methods to measure glenoid bone deficiency is adequate; however, 91% of the experts thought that an en face view of the glenoid using 3D CT provides the most accurate method. Ninety-five percent of the experts agreed that Hill-Sachs lesions are poorly quantified and classified by current imaging systems. Ninety percent of the experts agreed that in cases with a glenoid bone deficit greater than 20%, glenoid bone graft reconstruction should be performed and any of the available options is valid. There was no consensus among experts on how Hill-Sachs injuries should be managed or on how postoperative rehabilitation should be carried out., Conclusions: The essential statements on which the experts reached consensus included the following: A history of multiple dislocations and failed soft-tissue surgery should make surgeons consider the possibility of an associated bone deficit. Three-dimensional CT is the most accurate diagnostic method to evaluate and quantify bone loss. Although any of the available methods to measure glenoid bone deficiency is adequate, an en face view of the glenoid using 3D CT provides the most accurate method. Hill-Sachs lesions are poorly quantified and classified by current imaging systems. Finally, in cases with a glenoid bone deficit greater than 20%, glenoid bone graft reconstruction should be performed., Level of Evidence: Level V, consensus statement., (Copyright © 2021 Arthroscopy Association of North America. Published by Elsevier Inc. All rights reserved.)

Reverse total shoulder arthroplasty (RTSA) was originally developed because of unsatisfactory results with anatomic shoulder arthroplasty options for the majority of degenerative shoulder conditions and fractures.After initial concerns about RTSA longevity, indications were extended to primary osteoarthritis with glenoid deficiency, massive cuff tears in younger patients, fracture, tumour and failed anatomic total shoulder replacement.Traditional RTSA by Grammont has undergone a number of iterations such as glenoid lateralization, reduced neck-shaft angle, modular, stemless components and onlay systems.The incidence of complications such as dislocation, notching and acromial fractures has also evolved.Computer navigation, 3D planning and patient-specific implantation have been in use for several years and mixed-reality guided implantation is currently being trialled.Controversies in RTSA include lateralization, stemless humeral components, subscapularis repair and treatment of acromial fractures. Cite this article: EFORT Open Rev 2021;6:189-201. DOI: 10.1302/2058-5241.6.200085., Competing Interests: ICMJE Conflict of interest statement: GW reports consulting fees, Support for travel to meetings for study or other purposes and royalties from Wright, related to the submitted work. The other authors declare no conflict of interest relevant to this work., (© 2021 The author(s).)

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: This study aims to identify risk factors related to postoperative instability after reverse shoulder arthroplasty and evaluate the modalities and results of treatments in a large series of patients, with medium to long-term follow-up., Methods: Retrospective multicenter series of 1035 consecutive Grammont type reverse shoulder arthroplasties implanted between 1992 and 2010. 19.9% had a reverse shoulder arthroplasty with bony lateralization on the glenoid side. Patients were reviewed and radiographed with minimum five years' follow-up., Results: At a mean follow-up of eight years, the overall rate of postoperative instability was 3.0%. Instability was more frequent in case of reverse shoulder arthroplasty for revision surgery, in younger patients, in case of scapular notching, and tuberosity resorption. Lateralized reverse shoulder arthroplasties were associated with a lower instability rate. A reoperation to restore stability was needed in 70% of cases. The improvement in Constant Score was lower in patients with unstable reverse shoulder arthroplasties when compared to stable reverse shoulder arthroplasties., Conclusions: Younger patients are at higher risk for instability after Grammont type reverse shoulder arthroplasty implantation. Conversely, lateralized reverse shoulder arthroplasties resulted protective. When conservative treatment had failed, shoulder stability can be obtained with reoperation or prosthetic revision (needed in 70% of the cases), but to the price of lower functional results., Competing Interests: Declaration of Conflicting Interests: The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article., (© 2019 The British Elbow & Shoulder Society.)

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: Three-dimensional (3D) geometry of the normal glenohumeral bone anatomy and relations is poorly documented. Our aims were (1) to determine the 3D geometry of the normal glenohumeral joint (GHJ) with reference to the scapular body plane and (2) to identify spatial correlations between the orientation and direction of the humeral head and the glenoid., Methods: Computed tomographies (CTs) of the normal, noninjured GHJ were collected from patients who had undergone CTs in the setting of (1) polytrauma, (2) traumatic head injury, (3) chronic acromioclavicular joint dislocations, and (4) unilateral trauma with a contralateral normal shoulder. We performed 3D segmentation and measurements with a fully automatic software (Glenosys; Imascap). Measurements were made in reference to the scapular body plane and its transverse axis. Geometric measurements included version, inclination, direction, orientation, best-fit sphere radius (BFSR), humeral subluxation, critical shoulder angle, reverse shoulder angle, glenoid area, and glenohumeral distance. Statistical correlations were sought between glenoid and humeral 3D measurements (Pearson correlation)., Results: A total of 122 normal GHJs (64 men, 58 women, age: 52 ± 17 years) were studied. The glenoid BFSR was always larger than the humerus BFSR (constant factor of 1.5, standard deviation = 0.2). The mean glenoid version and inclination were -6° ± 4° and 7° ± 5°, respectively. Men and women were found to have significantly different values for inclination (6° vs. 9°, P = .02), but not for version. Humeral subluxation was 59% ± 7%, with a linear correlation with glenoid retroversion (r = -0.70, P < .001) regardless of age. There was a significant and linear correlation between glenoid and humeral orientation and direction (r = 0.72 and r = 0.70, P < .001)., Conclusion: The 3D geometry of the glenoid and humeral head present distinct limits in normal shoulders that can be set as references in daily practice: version and inclination are -6° and 7°, respectively, and humeral posterior subluxation is 59%; interindividual variations, regardless of the size, are relative to the scapular plane. There exists a strong correlation between the position of the humeral head and the glenoid orientation and direction., (Copyright © 2020 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.)

Hypothesis: The aim was to evaluate risk factors for complications, revision, and mid- to long-term outcomes after reverse shoulder arthroplasty (RSA) implanted for proximal humeral fracture sequelae (PHFS)., Methods: The radiographs of 98 patients (mean age, 68 years) who underwent RSA for the treatment of PHFS were reviewed at a minimum 5-year follow-up. PHFS were divided into 4 types according to the Boileau classification: type 1 (46 cases), type 2 (6 cases), type 3 (12 cases), and type 4 (34 cases). The tuberosities underwent osteotomy in 28 cases and excision in 12 (all type 3 or 4 PHFS). The mean follow-up period was 8.4 years (range, 5-14 years)., Results: The functional results and rate of RSA survival without revision (85% vs. 100% at 10 years, P = .007) were significantly lower for types 3 and 4 vs. types 1 and 2. Overall, our findings showed that RSA for PHFS is not the panacea that surgeons once believed: At a mean follow-up of 8.5 years (range, 5-14 years), 59% of the patients in our series had fair or poor results. Patients who underwent tuberosity osteotomy or excision had lower functional results (adjusted Constant score, 69% vs. 88%; P < .001), more postoperative complications (32% vs. 9%, P = .003), and a higher revision rate (15% vs. 2%, P = .017). Patients who underwent tuberosity osteotomy or excision at the time of RSA were at risk of postoperative prosthetic instability and humeral stem loosening. The absence of the greater tuberosity at last radiographic follow-up was predictive of higher rates of complications and revisions, as well as a poorer final outcome. Previous fracture fixation was associated with a higher rate of complete tuberosity resorption (56% vs. 33%, P = .026) and with higher rates of postoperative complications (27% vs. 13%, P = .099) and reinterventions (17% vs. 2%, P = .018)., Conclusion: The functional results and rates of complications and revision depend on the type of fracture sequelae and tuberosity management. Patients with more severe (type 3 and 4) fracture sequelae who undergo tuberosity osteotomy or excision are at risk of having a poorer functional result and higher rates of complications and revision with lower survival. Previous fracture fixation is also a prejudicial factor., (Copyright © 2020. Published by Elsevier Inc.)

Background: Cuff tear arthropathy (CTA) is characterized by superior migration of the humeral head with superior erosion of the glenoid. Rarely, humeral head migration can be anteroinferior with associated anterior erosion of the glenoid, a pattern described by Favard as the type E4 glenoid. The purpose of this retrospective imaging study was to analyze the 2D and 3D characteristics of the E4 glenoid., Methods: A shoulder arthroplasty database of 258 cuff tear arthropathies was examined to identify patients with an E4 type deformity. This resulted in a study cohort of 15 females and 2 males with an average age of 75 years. All patients had radiographs and CT scans available for analysis. CT-scan DICOM (Digital Imaging and Communications in Medicine) data were uploaded to a validated three-dimensional (3D) imaging software. Muscle fatty infiltration, glenoid measurements (anteversion, inclination), and humeral head subluxation according to the scapular plane were determined., Results: The mean anteversion and inclination of the E4 cohort were 32° ± 14° and -5° ± 2, respectively. The mean anterior subluxation was 19% ± 16%. All cases had severe grade 3 or 4 fatty infiltration of the infraspinatus, whereas only 65% had grade 3 or 4 subscapularis fatty infiltration. A significant correlation existed between glenoid anteversion and humeral head subluxation ( p < 0.001), but no correlation was found with muscle fatty infiltration. The CT analysis demonstrated an acquired erosive biconcave morphology in 11 patients (65%) and monoconcavity in 6 patients (35%)., Conclusion: The E4 type glenoid deformity in cuff tear arthropathy is characterized by an anterior erosion and anteversion associated with anterior subluxation of the humeral head., Competing Interests: The authors declare no conflict of interest.

Background: The degree of preoperative osteoarthritis has been shown to influence the postoperative outcome and the patients' satisfaction rate in hip and knee joint replacement surgery. However, no corresponding information is available for total shoulder arthroplasty (TSA). We therefore set out to evaluate the influence of preoperatively measured end-stage osteoarthritis on the postoperative clinical outcome of TSA., Methods: A retrospective analysis of 103 anatomic total shoulder replacements (96 patients) was performed. Patients were evaluated radiologically with X-rays in two planes and clinically using the Constant and Murley score (CS) and the self-reported satisfaction with the result. The degree of osteoarthritis was radiographically analyzed with the aid of the classifications according to Kellgren/Lawrence, Gerber, Guyette, and Allain and according to whether complete narrowing of the glenohumeral joint was present or not [bone-on-bone contact (BOB) or no bone-on-bone contact (No BOB)]., Results: The clinical results of TSA did not differ significantly among the various stages of osteoarthritis in any of the classifications (p > 0.05). The CS was significantly higher postoperatively for both the BOB and the No BOB group (p < 0.0001). Patients with BOB had a significantly lower CS preoperatively than patients with No BOB (p = 0.0172). In addition, the preoperative pain level was significantly higher in patients with BOB (p = 0.014). Postoperatively, no significant difference in CS (p = 0.6738) was found between the BOB group and the No BOB group. The mean improvement in CS was not statistically significant (p = 0.2218)., Conclusion: In contrast to hip and knee joint replacement procedures, a milder grade of osteoarthritis does not adversely influence the functional result or subjective satisfaction rate after TSA. The degree of osteoarthritis on conventional X-rays has no bearing on the postoperative clinical outcome. Therefore, the decision on when to carry out anatomic total shoulder arthroplasty should depend on the patient's pain level and loss of quality of life.

Background: The Walch type B pattern of glenohumeral osteoarthritis is characterized by posterior humeral head subluxation (PHHS). At present, it is unknown whether the percentage of subluxation measured on axillary radiographs is consistent with measurements on 2-dimensional (2D) axial or 3-dimensional (3D) volumetric computed tomography (CT). The purpose of this study was to evaluate PHHS across imaging modalities (radiographs, 2D CT, and 3D CT)., Methods: A cohort of 30 patients with Walch type B shoulders underwent radiography and standardized CT scans. The cohort comprised 10 type B1, 10 type B2, and 10 type B3 glenoids. PHHS was measured using the scapulohumeral subluxation method on axillary radiographs and 2D CT. On 3D CT, PHHS was measured volumetrically. PHHS was statistically compared between imaging modalities, with P ≤ .05 considered significant., Results: The mean PHHS value for the entire group was 69% ± 24% on radiographs, 65% ± 23% with 2D CT, and 74% ± 24% with 3D volumetric CT. PHHS as measured on complete axillary radiographs was not significantly different than that measured on 2D CT ( P  = .941). Additionally, PHHS on 3D volumetric CT was 9.5% greater than that on 2D CT ( P < .001). There were no significant differences in PHHS between the type B1, B2, and B3 groups with 2D or 3D CT measurement techniques ( P > .102)., Conclusion: Significant differences in PHHS were found between measurement techniques ( P < .035). A 9.5% difference in PHHS between 2D and 3D CT can be mostly accounted for by the linear (2D) vs. volumetric (3D) measurement techniques (a linear 80% PHHS value is mathematically equivalent to a volumetric PHHS value of 89.6%). Surgeons should be aware that subluxation values and therefore thresholds vary across different imaging modalities and measurement techniques., (© 2020 The Author(s).)

Background: Recent studies have shown variations in glenoid bone density in asymmetric wear patterns but have yet to analyze non-arthritic or concentrically worn glenoids., Questions/purposes: The purpose of this study is to characterize and compare subchondral glenoid bone densities in both non-arthritic and A1, A2, B1, B2 and B3 osteoarthritic glenoids, as well as to assess uniformity in symmetric and asymmetric erosion wear patterns., Methods: In all, 150 computerized tomography (CT) scans containing equal numbers of non-arthritic (N), A1, A2, B1, B2 and B3 glenoids were segmented semi-automatically. Each reconstructed glenoid was divided first into anterior and posterior quadrants, and then further subdivided into four quadrants. Volumes of interest (VOI) were defined at depths of 0-2.5mm (Zone A), 2.5-5mm (Zone B) and 5-7.5mm (Zone C). Average bone densities were measured at each VOI depth and in each quadrant., Results: Osteoarthritic glenoids had higher mean bone densities than N glenoids. Mean bone densities were uniform amongst all quadrants for N glenoids, but not for osteoarthritic glenoids. In A1 glenoids, the antero-superior quadrant was less dense in Zone C. A2 glenoids had increased bone density measured posteriorly in Zones B and C. In B1 and B2 glenoids, Zones B and C demonstrated increased bone densities of posterior quadrants compared to anterior quadrants. B3 glenoids presented similar results as A1 and A2 glenoids. Cystic changes were more pronounced in anterior quadrants of A2, B1, B2 and B3 glenoids., Conclusion: This study demonstrates that osteoarthritic glenoids have greater bone density than non-arthritic glenoids, independent of depth of interest. It also confirms that N glenoids have uniform erosion wear patterns and that B1 and B2 glenoids have irregular wear patterns. It is the first study to reveal that A1, A2 and B3 glenoids, though geometrically symmetrical, have irregular bony densities similar to B2 glenoids. These findings have clinical implications for reaming the glenoid and implant fixation., Level of Evidence: Basic Science, Anatomy, Imaging., (Copyright © 2020 Elsevier Masson SAS. All rights reserved.)

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.)

We report the case of a 74-year-old woman who sustained a scapular spine (SS) fracture after a fall 4 weeks after reverse shoulder arthroplasty (RSA). Open reduction and internal fixation (ORIF) with locked 90°-double plating resulted in union of the SS fracture with a good outcome (subjective shoulder value: 80%; Constant score 67; 1 year) despite of an adjacent lateral acromion fracture 3 weeks after ORIF. This is the second description in the literature of a successful double plate ORIF with union of an SS fracture after RSA. SS fractures are known to lead to poor RSA outcomes with a high mal-union rate and non-union rate. We describe the positioning of the plates and technical steps for successful ORIF to avoid complications, discuss the aftercare and report the outcome., Competing Interests: Competing interests: None declared., (© BMJ Publishing Group Limited 2020. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

Background: The purpose of this study was 2-fold: (1) to quantify type E2 bone loss orientation and its association with rotator cuff fatty infiltration and (2) to examine reverse baseplate designs used to manage type E2 glenoids., Methods: Computed tomography scans of 40 patients with type E2 glenoids were examined for pathoanatomic features and erosion orientation. The rotator cuff fatty infiltration grade was compared with the erosion orientation angle. To compare reconstructive options in light of the pathoanatomic findings, virtual implantation of 4 glenoid baseplate designs (standard, half wedge, full wedge, and patient-matched) was conducted to determine the volume of bone removal for seating and impingement-free range of motion., Results: The mean type E2 erosion orientation angle was 47° ± 17° from the 0° superoinferior glenoid axis, resulting in the average erosion being located in the posterosuperior quadrant directed toward the 10:30 clock-face position. The type E2 neoglenoid, on average, involved 67% of the total glenoid surface (total surface area, 946 ± 209 mm 2 ; neoglenoid surface area, 636 ± 247 mm 2 ). The patient-matched baseplate design resulted in significantly (P ≤ .01) less bone removal (200 ± 297 mm 3 ) for implantation, followed by the full-wedge design (1228 ± 753 mm 3 ), half-wedge design (1763 ± 969 mm 3 ), and standard (non-augmented) design (4009 ± 1210 mm 3 ). We noted a marked difference in erosion orientation toward a more superior direction as the subscapularis fatty infiltration grade increased from grade 3 to grade 4 (P < .001)., Conclusion: The average type E2 erosion orientation was directed toward the 10:30 clock-face position in the posterosuperior glenoid quadrant. This orientation resulted in the patient-matched glenoid augmentation requiring the least amount of bone removal for seating, followed by the full-wedge, half-wedge, and standard designs. Implant selection also substantially affected computationally derived range of motion in external rotation, flexion, extension, and adduction., (Copyright © 2019 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.)

Introduction: Recurrent anterior glenohumeral instability has been studied in the young population and limited evidence is available for adolescent patients. Our study is a retrospective review of patients aged <17 years who underwent open Latarjet procedure., Methods: Forty-five patients were available for review. Clinical outcomes were assessed by range of movements, stability, Walch-Duplay score (WDS), Rowe score (RS), Constant-Murley score (CMS), Subjective Shoulder Value (SSV), and return to sport. Radiographs were reviewed for osteoarthritis and complications., Results: The median age of patients was 15.7 years (13-17), and 56% had hyperlaxity. The median follow-up time was 6.6 years (3-26). The median postoperative movements showed recovered elevation (175°), external rotation (60°), and internal rotation (T9 level). Seventy-five percent of patients returned to the same level of sport, and 98% were satisfied. Clinical outcomes showed WDS, RS, and CMS scores of 85, 95, and 84 points, respectively, and an SSV of 95%. Twenty percent of patients described mild postoperative pain, and 1 had persistent stiffness. Other complications included 24% subjective apprehension, 4% redislocation, 4% wound problems, and 2% infection. Nine percent of cases had postoperative arthritis. The overall reoperation rate was 11%: 1 open washout for infection and 4 arthroscopic screw removal due to persistent pain. We found that hyperlaxity, female sex, and large or deep Hill-Sachs lesions were frequently associated with persistent apprehension at the last follow-up., Conclusions: The open Latarjet procedure provides a low rate of recurrent instability with acceptable complication rates in the long term for skeletally immature patients. It is an effective, safe treatment option without any significant glenoid growth disturbance., (Copyright © 2019 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.)

Background: We evaluated the pre-operative factors affecting anatomical and reverse total shoulder arthroplasty (TSA and RTSA) indications in primary osteoarthritis and compared outcomes in patients aged 70 years and older., Methods: Fifty-eight patients received a TSA with an all-polyethylene glenoid component (APGC) or an RTSA with/without glenoid lateralization and the same curved short-stem humeral component. Active anterior and lateral elevation (AAE, ALE), internal and external rotation (IR, ER), pain, and the Constant-Murley score (CS) were recorded pre and post-operatively. Pre-operative rotator cuff (RC) fatty infiltration (FI) and modified Walch glenoid morphology were assessed. Humeral and glenoid component radiological outcomes were recorded., Results: RTSA were older than TSA patients (p = 0.006), had lower pre-operative AAE (p < 0.001), ALE (p < 0.001), IR (p = 0.002), pain (p = 0.008) and CS (p < 0.001), and greater supraspinatus FI (p < 0.001). At a mean of 28.8 months, both implants yielded significantly different post-operative scores and similar complication rates. Both groups achieved similar post-operative AAE, ER, and IR; ALE was higher in TSA (p = 0.006); and AAE and ALE delta scores were higher in RTSA (p = 0.045 and p = 0.033, respectively). Radiolucent line rates were higher around the TSA APGC than the RTSA baseplate (p = 0.001). High-grade RC FI adversely affected mobility improvement. Humeral cortical thinning was significantly higher in TSA (p = 0.001)., Conclusion: RTSA patients were older, had poorer pre-operative active mobility, and had greater RC FI than TSA. Both devices provided good mid-term clinical and ROM improvement.

Background: An eccentric glenosphere (EG) has been proposed as a way of preventing scapular notching after reverse shoulder arthroplasty (RSA). Our aim was to report the midterm clinical and radiographic results of EG after RSA. A number of the patients described here were included in a previous study with short-term follow-up. The current retrospective study gave us the opportunity to follow many of these patients for a longer period of time., Methods: A retrospective analysis of prospectively collected data was conducted. Statistical significance was set at P < .001. Forty-nine RSAs with an EG and at least 60 months of follow-up were included. Range of motion (ROM), Constant scores (CSs), and Subjective Shoulder Value (SSV) were assessed. Scapular notching was graded according to the Sirveaux classification., Results: At the last follow-up, the mean improvement in active elevation (ROM) was 46° and the mean CS increased by nearly 31 points (both groups P < .001). The final SSV was 70%. Twenty-one patients (43%) had scapular notching, but in two-thirds of patients it was low-grade., Conclusion: The use of an EG provided excellent clinical outcomes that persisted with midterm follow-up. The rate of notching was lower than in other studies with EGs, but further studies are required to confirm this. An EG was safe and there were no issues with baseplate loosening or failure., (Copyright © 2019 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.)

Background: Our aim was to analyze the epidemiology, etiologies, and revision options for failed shoulder arthroplasty from 2 tertiary centers., Methods: From 1993 to 2013, 542 failed arthroplasties were revised in 540 patients (65% women): 224 hemiarthroplasties (HAs, 41%), 237 anatomic total shoulder arthroplasties (TSAs, 44%) and 81 reverse total arthroplasties (RSAs, 15%). Data about patients, pathology, and reintervention procedures, as well as intraoperative data, were analyzed from our 2 local registries that prospectively captured all the revision procedures. Patients had an average follow-up period of 8.7 years., Results: The revision rate was 12.7% for HAs, 6.7% for TSAs, and 3.9% for RSAs. HAs were revised earlier (33 ± 40 months) than RSAs (47 ± 150 months) and TSAs (69 ± 61 months). Glenoid failure was a major cause of reintervention: erosion in HAs (29%) or loosening in TSAs (37%) and RSAs (24%). Instability was another major cause of reintervention: 32% in RSAs, 20% in TSAs, and 13% in HAs. Humeral implant loosening led to revision in 10% of RSAs, 6% of HAs, and 6% of TSAs. Multiple reinterventions were required in 21% of patients, mainly for instability (26%) and/or infection (25%). The final implant was an RSA in 48%, especially when associated with cuff insufficiency, instability, and/or bone loss. Final reimplantation was possible in 90% of cases, with the remaining 10% treated with a resection or spacer., Conclusion: Glenoid failure and instability are the most common causes of revision. Soft-tissue insufficiency and/or infection results in multiple revisions. Surgeons must recognize all complications so that they can be addressed at the first revision operation and avoid further reinterventions. RSA was the most common final revision implant., (Copyright © 2019. Published by Elsevier Inc.)