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Background: Over-prescription of opioids in the United States increases risks of opioid dependence, overdose, and death. Increased perioperative and postoperative opioid use during orthopedic shoulder surgery is a significant risk factor for long term opioid dependence. The authors hypothesized that a multidisciplinary perioperative pain management program (Transitional Pain Service or TPS) for major shoulder surgery would lead to a reduced amount of opioids required postoperatively., Methods: A TPS was implemented at a Veterans Affairs Medical Center focused on non-opioid pain management and cessation support. Opioid consumption during the implementation of the TPS was compared to a historical cohort. All patients undergoing shoulder arthroplasty or rotator cuff repair were included. The primary outcome was the proportion of patients continuing opioid use at 90 days postoperatively. Secondary outcomes included postoperative pain scores, time to opioid cessation, and median opioid tablets consumed at 90-days. A multivariable model was developed to predict total opioid use at 90-days postoperatively. Kaplan Meier curves were calculated for time to opioid cessation., Results: The TPS group demonstrated decreased persistent opioid use at 90 days post-discharge (12.6% vs. 28.6%; p=0.018). Independent predictors associated with increased total opioid tablet prescriptions at 90 days included length of stay (β=19.17), anxiety diagnosis (β=37.627), and number of tablets prescribed at discharge (β=1.353). Shoulder arthroplasty surgery (TSA) was associated with decreased 90-day opioid utilization (β= -32.535) when compared to cuff repair (RCR). Median time to cessation was shorter in TSA (6 days) when compared with RCR (8 days). Pain scores were reduced compared to population mean by post-discharge day 2 for TSA and by post-discharge day 7 for RCR. Median number of post-discharge opioid tablets (oxycodone 5 mg) consumed under TPS management was 25 in both RCR and TSA surgery groups (180 MME)., Discussion and Conclusions: This study demonstrates that a TPS reduces the amount of opioid use of patients undergoing shoulder arthroplasty or cuff repair at 90 days when compared with a historical control. Multivariable regression indicated that fewer opioid tablets at discharge was a modifiable factor that may aid in reducing opioid consumption and that anxiety diagnosis, increased length of stay, and cuff repair surgery were other factors independently associated with increased opioid consumption. This data will assist surgeons in counseling patients, setting narcotic use expectations, and minimizing overprescribing. Use of a similar multidisciplinary perioperative pain management program may greatly reduce opioid over prescriptions nationally., (Copyright © 2024. Published by Elsevier Inc.)

Background: One method to augment rotator cuff repair is to pass dermal allograft pledgets along the sutures that bridge from the medial to the lateral row. It remains unclear whether this augmentation method alters repair biomechanics., Methods: This was a controlled laboratory study. After an a priori power analysis, 9 pairs of rotator cuffs underwent double-row suture bridge rotator cuff repair, half randomized to augmentation with dermal allograft pledgets passed along the suture bridge sutures. Repairs were then mounted on a material testing system and loaded cyclically 500 cycles to measure applied force and displacement. Repairs then underwent ultimate failure testing, and stiffness, ultimate failure force, and ultimate failure displacement were measured. Paired t tests were performed to compare between groups., Results: There were no differences between groups in construct gapping with cyclic loading after 500 cycles (P = .885). There were no differences between the augmented and control groups in yield force (103.5 ± 5.0 vs. 101.4 ± 5.9 N, respectively, P = .183), stiffness (94.2 ± 13.9 vs. 90.9 ± 13.8, P = .585), or ultimate failure force (255.3 ± 65.8 vs. 285.3 ± 83.2, P = .315). There were no differences between groups in failure modes, with most specimens failing by cuff tissue tearing within or medial to the construct., Conclusion: The addition of dermal allograft pledgets does not positively or negatively influence the time-zero biomechanical characteristics of double-row suture bridge rotator cuff repair., (Copyright © 2024. Published by Elsevier Inc.)

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: Preoperative planning is an integral aspect of managing complex deformity in reverse shoulder arthroplasty (RSA). The purpose of this study was to compare the success of patient specific instrumentation (PSI) and 3D computer-assisted planning with standard instrumentation (Non-PSI) in achieving planned corrections of the glenoid among patients undergoing RSA with severe bony deformity requiring glenoid bone grafts., Methods: A retrospective case-control study was performed, including all patients that underwent RSA with combined bone grafting procedures (BIO-RSA or structural bone grafting) for severe glenoid deformity by a single between June 2016 and July 2023. Patients were required to have preoperative and postoperative CT scans as well as preoperative 3D planning performed for inclusion. Patients were divided into two groups based on the use of 3D computer-assisted planning with or without PSI (PSI vs. Non-PSI). The corrected inclination and version were measured by two separate reviewers on preoperative and postoperative 2D CT scans and compared to their corresponding preoperative planning goals utilizing bivariate analyses., Results: We identified 45 patients that met our inclusion criteria (22 PSI and 23 Non-PSI). Preoperative inclination (mean ± SD) (PSI 10.12° ± 15.86°, Non-PSI 9.43° ± 10.64°; P = 0.864) and version (PSI -18.78° ± 18.3°, Non-PSI -17.82° ± 11.49°; P = 0.835) measurements were similar between groups. No significant differences in the mean deviation (error) between the postoperative and planned inclination (PSI 5.49° ± 3.72; Non-PSI 6.91° ± 5.05; P = 0.437) and version (PSI 8.37° ± 5.7; Non-PSI 5.37° ± 4.43; P = 0.054) were found between groups. No difference in the rate of outliers (>10° error) was noted in inclination (P = 0.135) or version (P = 0.445) between groups. Greater planned version correction was correlated with greater error when PSI was utilized (PSI r = 0.519, P = 0.013; Non-PSI r = 0.362, P = 0.089)., Conclusion: Both PSI and 3D computer-assisted planning without PSI (Non-PSI) appear to be useful techniques to achieve version and inclination correction among patients undergoing RSA with severe glenoid deformity required glenoid bone grafting with no clear superiority of one method over the other. Surgeons should be aware that when utilizing PSI, slightly greater error in achieving version goals may occur as version correction is increased., (Copyright © 2024. Published by Elsevier Inc.)

Background: The purpose of this study was to evaluate the relationship between multiple radiographic measures of lateralization and distalization and clinical outcome scores after a reverse total shoulder arthroplasty (RTSA)., Methods: We retrospectively evaluated all RTSAs performed by the senior author between January 1, 2007, and November 1, 2017. We then evaluated the visual analog scale for pain (VAS pain), Simple Shoulder Test (SST), and American Shoulder and Elbow Surgeons (ASES) scores and complication and reoperation rates at a minimum of 2-year follow-up. We measured preoperative and postoperative (2-week) radiographs for the lateralization shoulder angle (LSA), the distalization shoulder angle (DSA), lateral humeral offset, and the distance from the glenoid to the lateral aspect of the greater tuberosity. A multivariable analysis was performed to evaluate the effect of the postoperative radiographic measurements on final patient-reported outcomes (ASES scores, SST, and VAS pain)., Results: The cohort included 216 shoulders from unique patients who had patient-reported outcome scores available at a minimum of 2-year follow-up (average, 4.0 ± 1.9 years) for a total follow-up rate of 70%. In the multivariable models, more lateralization (LSA) was associated with worse final ASES scores -0.52 (95% confidence interval [CI]: -0.88, -0.17; P = .004), and more distalization (DSA) was associated with better final ASES scores 0.40 (95% CI: 0.11, 0.69; P = .007). More lateralization (LSA) was associated with worse final SST scores -0.06 (95% CI: -0.11, -0.003; P = .039). Finally, greater distalization (DSA) was associated with lower final VAS pain scores, ratio = 0.98 (95% CI: 0.96, 1.00; P = .021)., Conclusions: Greater distalization and less lateralization are associated with better function and less pain after a Grammont-style RTSA. When using a Grammont-style implant, remaining consistent with Grammont's principles of implant placement will afford better final clinical outcomes., (Copyright © 2024 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.)

Background: Operative treatment of scapulothoracic bursitis most commonly comprises arthroscopic scapulothoracic bursectomy with or without partial superomedial angle scapuloplasty. There is currently no consensus regarding whether or when scapuloplasty should be performed. Prior studies are limited to small case series, and optimal surgical indications are not yet established. The purposes of this study were (1) to retrospectively review patient-reported outcomes of arthroscopic treatment of scapulothoracic bursitis and (2) to compare outcomes between scapulothoracic bursectomy alone and bursectomy with scapuloplasty. We hypothesized that bursectomy with scapuloplasty would provide superior pain relief and functional improvement., Materials and Methods: All cases of scapulothoracic débridement with or without scapuloplasty completed at a single academic center from 2007 through August 2020 were reviewed. Patient demographic characteristics, symptomatology data, physical examination findings, and corticosteroid injection response data were collected from the electronic medical record. Visual analog scale pain, American Shoulder and Elbow Surgeons, Simple Shoulder Test, and Single Assessment Numeric Evaluation scores were collected. Comparisons between the group undergoing bursectomy alone and the group undergoing bursectomy with scapuloplasty were made using the Student t test for continuous variables and the Fisher exact test for categorical variables., Results: Thirty patients underwent scapulothoracic bursectomy alone, and 38 patients underwent bursectomy with scapuloplasty. Final follow-up data were available for 56 of 68 cases (82%). Final postoperative visual analog scale pain scores (3.4 ± 2.2 and 2.8 ± 2.2, respectively; P = .351), American Shoulder and Elbow Surgeons scores (75.8 ± 17.7 and 76.5 ± 22.5, respectively; P = .895), and Simple Shoulder Test scores (8.8 ± 2.3 and 9.5 ± 2.8, respectively; P = .340) were similar between the bursectomy-alone and bursectomy-with-scapuloplasty groups., Conclusion: Both arthroscopic scapulothoracic bursectomy alone and bursectomy with scapuloplasty are effective treatments for scapulothoracic bursitis. Operative time is shorter without scapuloplasty. In this retrospective series, these procedures showed similar outcomes regarding shoulder function, pain, surgical complications, and rates of subsequent shoulder surgery. Further studies with a focus on 3-dimensional scapular morphology may help optimize patient selection for each of these procedures., (Copyright © 2023 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.)

Background: The glenoid labrum acts as a bumper, deepening glenoid concavity and amplifying the concavity-compression mechanism, and serves as the scapular attachment for glenohumeral ligaments. The role of the posterosuperior labrum in anteroinferior glenohumeral stability, and the role of the anterior labrum in posterior stability has been debated. The purpose of this study was to quantify the contribution of anteroinferior and posterosuperior labral tears to loss of glenohumeral stability in multiple directions., Methods: Fourteen fresh-frozen cadaveric shoulders were tested on a custom stability ratio measurement apparatus. The peak force that was required to translate the humeral head in anterior, anteroinferior, posterior, and posteroinferior directions was measured under 5 conditions: intact labrum (n = 14), anteroinferior labral tear (n = 7), posterosuperior labral tear (n = 7), combined labral tear (n = 14), and no labrum (n = 14). The stability ratio was defined as the peak translational force divided by the compressive force. Within force-translation curves, we defined the suction cup effect as the force required to release the negative pressure created by an intact labrum., Results: The suction cup effect was usually present with the intact labrum and always disappeared after removal of the labrum for anterior (100% vs. 0%) and posterior (86% vs. 0%) translations (P < .001). After creation of an anteroinferior labral tear, the stability ratio for posterior direction decreased (P < .001) and the suction cup effect disappeared (P < .001). After creation of a posterosuperior labral tear, stability ratios in the anterior and anteroinferior directions decreased (P ≤ .006) and the suction cup effect disappeared (P ≤ .015). The stability ratio for anterior and anteroinferior testing was more diminished by posterosuperior labral tears than anteroinferior labral tears, and the stability ratio for posterior testing was more diminished by anteroinferior labral tears than posterosuperior labral tears., Conclusion: Anteroinferior labral tears decreased posterior stability and posterosuperior labral tears decreased anterior and anteroinferior stability, largely because of loss of the suction cup effect., (Copyright © 2022 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.)

Objective: To compare range of motion (ROM) and patient-reported outcomes (PROs) between a structured home exercise program (HEP) and active, supervised physiotherapy (PT) after primary Reverse total shoulder arthroplasty (RTSA) by performing a multicenter randomized clinical trial., Methods: Patients undergoing primary RTSA at 2 centers were randomized to either a HEP group, in which they were given a handout and a rope pulley, or a PT group, in which they were given a standardized prescription. Surgical technique and implants were standardized. At baseline, 6 weeks, 3 months, and 1 year postoperatively, we obtained American Shoulder and Elbow Surgeons scores, Western Ontario Osteoarthritis Scores, visual analogue scale for pain scores, and measured ROM via videotape. On video, ROM was then measured by blinded observers. At all study visits, patients were asked how many days per week they were in PT and how many days a week they completed HEP to determine compliance and crossover. An a priori power analysis suggested 29 patients per group, 56 patients total to detect a difference of 30° in active forward elevation with a power of 0.8 at a 2-sided alpha of 0.05., Results: 89 patients were randomized, 43 to PT, and 46 to HEP. We obtained 1-year PRO follow-up on 83 patients (93%) and ROM follow-up on 73 patients (82%). Nine patients (20%) crossed over from HEP to PT and 2 patients (4%) crossed over from PT to HEP. Complications occurred in 13% of HEP and 17% of PT patients (P = .629). Using mixed models that account for baseline values, there were no significant differences between groups in PROs or ROM at final follow-up., Conclusion: In this 2-center, randomized clinical trial, there were no significant differences in patient outcomes or ROM between HEP and PT after RTSA. These findings suggest that it may not be necessary to recommend PT as a protocol for all patients after RTSA., (Copyright © 2023 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.)

Background: Internal rotation in adduction is often limited after reverse total shoulder arthroplasty (rTSA), but the origins of this functional deficit are unclear. Few studies have directly compared individuals who can and cannot perform internal rotation in adduction. Little data on underlying 3D humerothoracic, scapulothoracic, and glenohumeral joint relationships in these patients are available., Methods: Individuals >1-year postoperative to rTSA were imaged with biplane fluoroscopy in resting neutral and internal rotation in adduction poses. Subjects could either perform internal rotation in adduction with their hand at T12 or higher (high, N = 7), or below the hip pocket (low, N = 8). Demographics, the American Shoulder and Elbow Surgeons score, Simple Shoulder Test, and scapular notching grade were recorded. Joint orientation angles were derived from model-based markerless tracking of the scapula and humerus relative to the torso. The 3D implant models were aligned to preoperative computed tomography models to evaluate bone-implant impingement., Results: The Simple Shoulder Test was highest in the high group (11 ± 1 vs. 9 ± 2, P = .019). Two subjects per group had scapular notching (grades 1 and 2), and 3 high group and 4 low group subjects had impingement below the glenoid. In the neutral pose, the scapula had 7° more upward rotation in the high group (P = .100), and the low group demonstrated 9° more posterior tilt (P = .017) and 14° more glenohumeral elevation (P = .047). In the internal rotation pose, axial rotation was >45° higher in the high group (P ≤ .008) and the low group again had 11° more glenohumeral elevation (P = .058). Large rotational differences within subject groups arose from a combination of differences in the resting neutral and maximum internal rotation in adduction poses, not only the terminal arm position., Conclusions: Individuals who were able to perform high internal rotation in adduction after rTSA demonstrated differences in joint orientation and anatomic biases versus patients with low internal rotation. The high rotation group had 7° more resting scapular upward rotation and used a 15°-30° change in scapular tilt to perform internal rotation in adduction versus patients in the low group. The combination of altered resting scapular posture and restricted scapulothoracic range of motion could prohibit glenohumeral rotation required to reach internal rotation in adduction. In addition, inter-patient variation in humeral torsion may contribute substantially to postoperative internal rotation differences. These data point toward modifiable implant design and placement factors, as well as foci for physical therapy to strengthen and mobilize the scapula and glenohumeral joint in response to rTSA surgery., (Copyright © 2022 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.)

Background: The etiology of adhesive capsulitis involves inflammation, thickening, and fibrosis of the shoulder capsule. The underlying genetic factors are poorly understood. The purpose of this study was to identify genetic variants associated with adhesive capsulitis using the UK Biobank (UKB) cohort and compare them with variants associated with Dupuytren disease investigating a common etiology between the 2 fibrotic disorders., Methods: A genome-wide association study (GWAS) was performed using data from UKB with 10,773 cases of adhesive capsulitis, and a second GWAS was performed with 8891 cases of Dupuytren disease. Next, a comparison of association statistics was performed between adhesive capsulitis and Dupuytren disease using the data from both GWAS. Finally, single-nucleotide polymorphisms (SNPs) previously reported from candidate gene studies for adhesive capsulitis and Dupuytren disease were tested for association with adhesive capsulitis and Dupuytren disease using the summary statistics from their respective GWAS., Results: The UKB GWAS for adhesive capsulitis identified 6 loci that reached genome-wide statistical significance: a cluster of 11 closely linked SNPs on chromosome 1; a single SNP on chromosome 2; a single SNP on chromosome 14; 2 closely linked SNPs on chromosome 21; 33 closely linked SNPs on chromosome 22; and 3 closely linked SNPs on the X chromosome. These SNPs were associated with 8 different genes including TSPAN2/NGF, SATB2, MRPL52/MMP14, ERG, WNT7B, and FGF13. A GWAS for Dupuytren disease was performed and a comparison to the adhesive capsulitis GWAS showed 13 loci significantly associated with both phenotypes. A validation attempt of 6 previously reported SNPs associated with adhesive capsulitis using UKB summary statistics was unable to confirm any of the previously reported SNPs (all P > .19). All 23 previously reported SNPs associated with Dupuytren disease were confirmed using the UKB summary statistics (P < 2.1 × 10 -3 ) CONCLUSION: This GWAS investigating adhesive capsulitis has identified 6 novel loci involving 8 different genes to be associated with adhesive capsulitis. A GWAS investigating Dupuytren disease was performed and compared to the adhesive capsulitis GWAS, and 13 common loci were identified between the 2 disorders with genes involved in pathologic fibrosis. We were unable to validate the SNPs in candidate genes previously reported to be associated with adhesive capsulitis although we were able to confirm all previously reported SNPs associated with Dupuytren disease. The strong genetic overlap between the adhesive capsulitis and Dupuytren disease loci suggests a similar etiology between the 2 diseases., (Copyright © 2022 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.)

Background: Although muscle weakness and/or imbalance of the rotator cuff are thought to contribute to the development of shoulder instability, the association between muscular dysfunction and shoulder instability is not completely understood. The purpose of this study was to evaluate rotator cuff and deltoid muscle cross-sectional areas in different types of shoulder instability (anterior, posterior, and multidirectional instability [MDI]) and to determine the associations between muscular imbalance and shoulder instability direction., Methods: Preoperative magnetic resonance images of patients with shoulder instability who subsequently underwent arthroscopic glenohumeral labral repair or capsular plication were evaluated. Shoulder instability was classified into 3 categories by direction: (1) anterior, (2) posterior, and (3) MDI. The rotator cuff (supraspinatus, subscapularis, and infraspinatus + teres minor) and deltoid (anterior and posterior portions, and total) muscle areas were measured on T1 sagittal and axial slices, respectively. The ratios of the subscapularis to infraspinatus + teres minor area and the anterior deltoid to posterior deltoid area were calculated to quantify the transverse force couple imbalance., Results: A total of 189 patients were included, where each group consisted of 63 patients. The infraspinatus + teres minor muscle area was smaller than the subscapularis muscle area in the anterior instability group (P = .007). The subscapularis muscle area was smaller than the infraspinatus + teres minor muscle area in the posterior instability and MDI groups (P ≤ .003). The anterior deltoid muscle area was smaller than the posterior deltoid muscle area in all groups (P ≤ .001). The subscapularis-to-infraspinatus + teres minor area ratio in the anterior instability group (1.18 ± 0.40) was higher than that in the posterior instability and MDI groups (0.79 ± 0.31 and 0.93 ± 0.33, respectively; P < .001). There was no difference in the anterior deltoid-to-posterior deltoid area ratio among the 3 groups., Conclusion: Patients with anterior instability have smaller muscle area of the posterior rotator cuff as compared with the anterior rotator cuff. In contrast, patients with posterior instability and MDI have smaller muscle area of the anterior rotator cuff as compared with the posterior rotator cuff. Thus, the direction of shoulder instability is associated with rotator cuff muscle area., (Copyright © 2022 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.)

Background: Optimal implant placement in reverse total shoulder arthroplasty (rTSA) remains controversial. Specifically, the optimal glenoid inclination is unknown. Therefore, a cadaveric shoulder simulator with 3-dimentional human motion specific to rTSA was used to study joint contact and muscle forces as a function of glenoid component inclination., Methods: Eight human cadaver shoulders were tested before and after rTSA implantation. Scapular plane abduction kinematics from control subjects and those with rTSA drove a cadaveric shoulder simulator with 3-dimentional scapulothoracic and glenohumeral motion. Glenoid inclination varied from -20° to +20°. Outputs included compression, superior-inferior (S/I) shear, and anterior-posterior shear forces from a 6° of freedom load cell in the joint, and deltoid and rotator cuff muscle forces. Data were evaluated with statistical parametric mapping and t-tests., Results: Inferior glenoid inclination (-) reduced S/I shear by up to 125% relative to superior inclination, with similar compression to the neutral condition (0°). Superior inclinations (+) increased the S/I shear force by approximately the same magnitude, yet decreased compression by 25% in the most superior inclination (+20°). There were few differences in deltoid or rotator cuff forces due to inclination. Only the middle deltoid decreased by approximately 7% for the most inferior inclination (-20°). Compared with native shoulders, the neutral (0°) rTSA inclination showed reduced forces of 30%-75% in the anterior deltoid and a trend toward decreased forces in the middle deltoid. Force demands on the rotator cuff varied as a function of elevation, with a trend toward increased forces in rTSA at peak glenohumeral elevation., Conclusions: Inferior inclination reduces superior shear forces, without influencing compression. Superior inclination increased S/I shear, while decreasing compression, which may be a source of component loosening and joint instability after rTSA. Inferior inclination of the rTSA glenoid may reduce the likelihood of glenoid loosening by reducing the magnitude of cyclic shear and compressive loading during arm elevation activities, although this may be altered by specific-subject body habitus and motion. These factors are especially important in revision rTSA or glenoid bone grafting where there is already a 3-fold increase in glenoid baseplate loosening vs. primary rTSA., (Copyright © 2022 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.)

Background: During anatomic total shoulder arthroplasty (aTSA), the humeral head can be resected with or without the use of an intramedullary cutting guide, the former referred to as intramedullary (IM) resection and the latter referred to as freehand (FH) resection. Outcomes following aTSA are predicated upon the restoration of the native humeral anatomy, which can be more challenging with stemless implants. To date, no studies have determined which method of humeral head resection is superior in restoring native anatomy. Our purpose was to determine whether FH or IM resection was superior in restoring native anatomy during aTSA with stemless implants., Methods: A review of all patients who underwent aTSA using the stemless Tornier Simpliciti Shoulder System at two academic institutions by two separate surgeons between January 2017 and June 2020 was performed. One surgeon at one institution performed stemless aTSA using the IM resection technique, while the second surgeon utilized the FH resection technique. Patients were excluded if they underwent surgery for an indication other than glenohumeral osteoarthritis, if they received a short-stem or standard-stem implant, or if they lacked adequate preoperative and postoperative Grashey radiographs. One hundred eleven patients across both institutions (51 IM, 60 FH) were included for the final radiographic assessment. The humeral head height (HH) and neck-shaft angle (NSA) were measured on preoperative and postoperative Grashey radiographs. The centers of rotation (CORs) were measured on postoperative Grashey radiographs. Patients were classified as having acceptable restoration of their native anatomy if the change (Δ) in COR or HH was ≤3 mm and ≤ 5 mm, respectively, or if the postoperative NSA was ≥130°., Results: IM resection had the greatest acceptable restoration of COR (90.2% IM versus 70% FH, P = .009), HH (96.1% IM vs. 63.3% FH, P < .001), and NSA (96.1% IM vs. 78.3% FH, P = .006) relative to FH resection. The mean postoperative NSAs for the IM and FH cohorts were 134.4° (±2.1°) and 133.8° (±5.4°), respectively (P = .208). The mean ΔCORs for the IM and FH groups were 1.2 (±1.5) and 2.3 (±1.2) mm, respectively (P < .001). Finally, the mean ΔHHs for the IM and FH cohorts were 1.7 (±1.4) and 4.4 (±2.9) mm, respectively (P < .001)., Conclusions: Restoration of the native humeral anatomy following stemless aTSA occurred at a significantly higher rate when using IM vs. FH resection., (Copyright © 2022 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.)

Background: Although typically favorable in outcome, anatomic total shoulder arthroplasty (aTSA) can require long-term revision. The most common cause for revision is glenoid loosening, which may result from eccentric cyclic forces and joint translations. "Rocking" of the glenoid component may be exacerbated by the joint geometry, such as glenoid inclination and version. Restoration of premorbid glenoid inclination may be preferable, although laboratory and computational models indicate that both superior inclination and inferior inclination have benefits. This discrepancy may arise because previous studies were limited by a lack of physiological conditions to test inclination. Therefore, a cadaveric shoulder simulator with 3-dimensional human motion was used to study joint contact and muscle forces with isolated changes in glenoid inclination., Methods: Eight human cadaveric shoulders were tested before and after aTSA. Scapular-plane abduction kinematics from human subjects were used to drive a cadaveric shoulder simulator with 3-dimensional scapulothoracic and glenohumeral motion. Glenoid inclination was varied from -10° to +20°, whereas compressive, superior-inferior shear, and anterior-posterior shear forces were collected with a 6-df load cell during motion. Outputs also included muscle forces of the deltoid and rotator cuff. Data were evaluated with statistical parametric mapping repeated-measures analysis of variance and t tests., Results: Inferior glenoid inclination (-10°) reduced both compressive and superior-inferior shear forces vs. neutral 0° inclination by up to 40%, and even more when compared with superior inclination (P < .001). Superior inclinations (+10° and +20°) tended to increase deltoid and rotator cuff forces vs. neutral 0° inclination or inferior inclination, on the order of 20%-40% (P ≤ .045). All force metrics except anterior-posterior shear were lowest for inferior inclination. Most aTSA muscle forces for neutral 0° inclination were not significantly different from native shoulders and decreased 45% and 15% in the posterior deltoid and supraspinatus, respectively (P ≤ .003). Joint translations were similar to prior reports in aTSA patients and did not differ between any inclinations or compared with native shoulders. Joint reaction forces were similar to those observed in human subjects with instrumented aTSA implants, providing confidence in the relative magnitude of our results., Conclusions: Inferior inclination reduces overall forces in the shoulder. Superior inclinations increase the muscle effort required for the shoulder to achieve similar motion, thus increasing the forces exerted on the glenoid component. These results suggest that a preference toward aTSA glenoid components in inferior inclination may reduce the likelihood of glenoid loosening by reducing excessive muscle and joint contact forces., (Copyright © 2022 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.)

Background: The purpose of the study was to identify genetic variants associated with rotator cuff disease by performing a genome-wide association study (GWAS) for shoulder impingement using the UK Biobank (UKB) cohort and then combining the GWAS data with a prior GWAS for rotator cuff tears. The loci identified by the GWAS and meta-analysis were examined for changes in expression following rotator cuff tearing using RNA sequencing., Methods: A GWAS was performed using data from UKB with 3864 cases of shoulder impingement. The summary statistics from shoulder impingement and a prior study on rotator cuff tears were combined in a meta-analysis. Also, the previous association of 2 single-nucleotide polymorphisms (SNPs) with shoulder impingement from a published GWAS using the UKB was tested. Rotator cuff tendon biopsies were obtained from 24 patients with full-thickness rotator cuff tears who underwent arthroscopic rotator cuff repair (cases) and 9 patients who underwent open reduction internal fixation for a proximal humeral fracture (controls). Total RNA was extracted and differential gene expression was measured by RNA sequencing for genes with variants associated with rotator cuff tearing., Results: The shoulder impingement GWAS identified 4 new loci: LOC100506457, LSP1P3, LOC100506207, and MIS18BP1/LINC00871. Combining data with a prior GWAS for rotator cuff tears in a meta-analysis resulted in the identification of an additional 7 loci: SLC39A8/UBE2D3, C5orf63, ASTN2, STK24, FRMPD4, ACOT9/SAT1, and LINC00890/ALG13. Many of the identified loci have known biologic functions or prior associations with diseases, suggesting possible biologic pathways leading to rotator cuff disease. RNA sequencing experiments show that expression of STK24 increases whereas expression of SAT1 and UBE2D3 decreases following rotator cuff tearing. Two SNPs previously reported to show an association with shoulder impingement from a prior UKB GWAS were not validated in our study., Conclusion: This is the first GWAS for shoulder impingement in which new data from UKB enabled the identification of 4 loci showing a genetic association. A meta-analysis with a prior GWAS for rotator cuff tearing identified an additional 7 loci. The known biologic roles of many of the 11 loci suggest plausible biologic mechanisms underlying the etiology of rotator cuff disease. The risk alleles from each of the genetic loci can be used to assess the risk for rotator cuff disease in individual patients, enabling preventative or restorative actions via personalized medicine., (Copyright © 2021 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.)

Background: Restoration of muscular strength is predicated on restoration of muscle length. The purpose of this study was to describe infraspinatus and deltoid length preoperative to reverse total shoulder arthroplasty (RTSA) to guide distalization and lateralization to restore preoperative muscle length., Methods: This was a retrospective radiographic study. We measured the infraspinatus length on preoperative computed tomographic images and the deltoid length on preoperative radiographs. For all measurements, reliability was first established by comparing measurements between 2 observers, and intraclass correlation coefficients (ICCs) were calculated. We then calculated descriptive statistics for these muscle lengths and developed a formula to predict these muscle lengths from patient demographics., Results: We measured infraspinatus length in 97 patients and deltoid length in 108 patients. Inter-rater reliability was excellent, with all ICCs >0.886. The mean infraspinatus length was 15.5 cm (standard deviation 1.3) and ranged from 12.6-18.9 cm, whereas the deltoid length was 16.2±1.7 cm and ranged from 12.5-20.2 cm. Both infraspinatus (r = 0.775, P < .001) and deltoid length (r = 0.717, P < .001) were highly correlated with patient height but did not differ between diagnoses. Formulae developed through linear regression allowed prediction of muscle length to within 1 cm in 78% and within 2 cm in 100% for the infraspinatus and 60% and 88% for the deltoid., Conclusion: Deltoid and infraspinatus length are variable but highly correlated with patient height. To maintain tension, 2 mm of lateralization and distalization should be added for every 6 inches (∼15 cm) of height above average for a Grammont-style RTSA., (Copyright © 2020 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.)

Background: The etiology of rotator cuff tearing is likely multifactorial, including a potential genetic predisposition. The purpose of the study was to identify genetic variants associated with rotator cuff tearing utilizing the UK Biobank (UKB) cohort, confirm variants using a separate genetic database, and evaluate tissue expression of genes with associated variants following rotator cuff tearing using RNA sequencing., Methods: Genome-wide association study (GWAS): A GWAS was performed using data from UKB with 5701 cases of rotator cuff injury. RNA sequencing analyses: rotator cuff biopsies were obtained from 24 patients with full-thickness rotator cuff tears who underwent arthroscopic rotator cuff repair (cases) and 9 patients who underwent open reduction internal fixation for a proximal humerus fracture (controls). Total RNA was extracted and differential gene expression was measured by RNAseq for genes with variants associated with rotator cuff tearing., Results: The results of the UKB GWAS identified 3 loci that reached genome-wide statistical significance: 2 loci on chromosome 7 in GLCCI1 (rs4725069; P = 5.0E-09) and THSD7A (rs575224171; P = 5.3E-09), and 1 locus on chromosome 2 in ZNF804A (rs775583810; P = 3.9E-09). The association with rotator cuff injury of the GLCCI1 single-nucleotide polymorphism (SNP; rs4725069) was confirmed in the Kaiser Permanente Research Bank cohort (P = .008). Twenty previously reported SNPs in 12 genes were evaluated using summary statistics from the UKB GWAS, which confirmed 3 SNPs in TNC with rotator cuff injury (rs1138545, rs72758637, and rs7021589; all P < .0024). Of 17 genes with variants associated with rotator cuff injury (14 previously from literature plus 3 new genes from current UKB GWAS), TIMP2, Col5A1, TGFBR1, and TNC were upregulated (P < .001 for all) and THSD7A was downregulated (P = .005) in tears vs. controls in the RNA sequencing data set., Conclusion: The UKB GWAS has identified 3 novel loci associated with rotator cuff tearing (ZNF804A, GLCCI1, THSD7A). Expression of the THSD7A gene was significantly downregulated in rotator cuff tears vs. controls supporting a potential functional role. Three previously reported SNPs in the TNC gene were validated in the UKB GWAS, supporting a role for this gene in rotator cuff tearing. Finally, TIMP2, Col5A1, TGFBR1, and TNC genes were found to have significantly upregulated tissue expression in cases vs. controls supporting a biologic role in tearing for these genes., (Copyright © 2020 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.)

Background: The purpose of this study was to determine the factors associated with outcomes after reverse total shoulder arthroplasty (RTSA)., Methods: We retrospectively evaluated all RTSAs performed by the senior author between January 1, 2007, and November 1, 2017. We evaluated pain visual analog scale (VAS), Simple Shoulder Test (SST), and American Shoulder and Elbow Surgeons Standardized Shoulder Assessment Form (ASES) scores and complication and reoperation rates at a minimum of 2-year follow-up. We evaluated preoperative and 2-week postoperative radiographs for glenoid inclination (GI), medialization as distance between the center of the humeral head or glenosphere and the line of the deltoid, and distalization via the acromial-greater tuberosity distance. We performed inter- and intrarater reliabilities via intraclass correlation coefficients (ICCs) and conducted a multivariable analysis., Results: We included 230 RTSAs in the analysis, with 70% follow-up at a median of 3.4 years. Reliability was acceptable with all ICCs >.678. Increased postoperative GI was significantly associated with increased VAS pain postoperatively (P = .008). Increased distalization was associated with an increased rate of complications and reoperations (P = .032). Younger age (P = .008), female gender (P = .009), and lower body mass index (BMI) (P = .006) were associated with worse ASES scores. Female gender (P < .001) and lower BMI (P = .039) were associated with worse SST scores. Female gender (P = .013) and lower BMI (P = .005) were associated with worse VAS-pain scores., Conclusion: Age, gender, and BMI are associated with outcome after RTSA. In this retrospective analysis of a Grammont-style RTSA, superior inclination is associated with increased pain postoperatively, whereas excessive arm lengthening is associated with increased risk for complication or reoperation., (Copyright © 2020 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.)

Background: The purposes of this study were to determine whether acromial morphology (1) could be measured accurately on magnetic resonance images (MRIs) as compared to computed tomographs (CTs) as a gold standard, (2) could be measured reliably on MRIs, (3) differed between patients with rotator cuff tears (RCTs) and those without evidence of RCTs or glenohumeral osteoarthritis, and (4) differed between patients with rotator cuff repairs (RCRs) that healed and those that did not., Methods: This is a retrospective comparative study. We measured coronal, axial, and sagittal acromial tilt; acromial width, acromial anterior and posterior coverage, and glenoid version and inclination on MRI corrected into the plane of the glenoid. We determined accuracy by comparison with CT via intraclass correlation coefficients (ICCs). To determine reliability, these same measurements were made on MRI by 2 observers and ICCs calculated. We compared these measurements between patients with a full-thickness RCT and patients aged >50 years without evidence of an RCT or glenohumeral osteoarthritis. We then compared these measurements between those patients with healed RCRs and those with a retorn rotator cuff on MRI. In this portion, we only included patients with both a preoperative MRI and a postoperative MRI at least 1 year from RCR. Only those patients without tendon defects on postoperative MRIs were considered to be healed. In these patients, we also radiographically measured the critical shoulder angle., Results: In a validation cohort of 30 patients with MRI and CT, all ICCs were greater than 0.86. In these patients, the inter-rater ICCs of the MRI measurements were >0.53. In our RCT group of 110 patients, there was greater acromial width [mean difference (95% confidence interval) = 0.1 (0, 0.2) mm, P = .012] and significantly less sagittal acromial tilt [9° (5°-12°), P < .001] than in our comparison group of 107 patients. A total of 110 RCRs were included. Postoperative MRI scans were obtained at a mean follow-up of 24.2 ± 15.8 months, showing 84 patients (76%) had healed RCRs. Aside from acromial width, which was 0.2 mm different and thus did not have clinical significance, there was no association between healing and any of the measured morphologic characteristics. Patients with healed repairs had significantly smaller tears in terms of both width (P < .001) and retraction (P < .001)., Conclusion: Although the acromion is wider in RCTs, the difference of 0.1 mm likely has no clinical significance. The acromion is more steeply sloped from posteroinferior to anterosuperior in those with RCTs. These findings call into question subacromial impingement due to native acromial morphology as a cause of rotator cuff tearing. Acromial morphology, critical shoulder angle, and glenoid inclination were not associated with healing after RCR. This study does not support lateral acromioplasty., (Copyright © 2020 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.)

Background: Minimal clinically important differences (MCIDs) for different patient outcome scores have been reported for various shoulder diseases, including shoulder arthroplasty and the nonoperative treatment of rotator cuff disease. The purpose of this study was to assess the MCID for the American Shoulder and Elbow Surgeons Standardized Shoulder Assessment Form (ASES) score, the Simple Shoulder Test (SST), and a visual analog scale (VAS) measuring pain, after arthroscopic rotator cuff repair., Methods: A total of 202 patients who underwent arthroscopic rotator cuff repair were retrospectively reviewed. ASES, SST, and VAS pain scores were collected preoperatively and at 1 year postoperatively. The MCID was then calculated via a 4-question anchor-based method., Results: The MCID results for the ASES, SST, and VAS pain scores were 27.1, 4.3, and 2.4, respectively. Age at time of surgery, sex, anteroposterior tear size, and worker's compensation status were not associated with MCID values (P > .05)., Conclusion: The MCID values determined in the current study are higher than those previously identified for the nonoperative treatment of rotator cuff disease using the same anchor questions. Use of these higher values should be considered when evaluating improvements of individual patients after rotator cuff repair, to determine comparative effectiveness of various rotator cuff repair techniques and to determine sample sizes for prospective comparative trials of rotator cuff repair methods., (Copyright © 2019 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.)

Background: Large glenoid defects present a challenge during primary and revision reverse total shoulder arthroplasty (RTSA) especially when humeral head autograft is not available as a bone graft source. The purpose of this study was to evaluate the clinical and radiographic outcomes of RTSA with concomitant structural allografting to reconstruct large glenoid defects., Methods: From May 2008 to July 2016, 22 patients underwent primary or revision RTSA with structural glenoid allografting. Of 22 patients, 19 (86%) were available for a minimum 2-year clinical follow-up (average, 2.8 ± 1.3 years), and 17 of 22 (77%) were available for a minimum 1-year radiographic follow-up. Functional outcomes, range of motion, radiographic deformity correction, allograft incorporation, and complication rates were determined., Results: From preoperatively to postoperatively, significant improvements in the average Simple Shoulder Test score (2 ± 2 preoperatively vs. 10 ± 8 postoperatively, P = .002), the average American Shoulder and Elbow Surgeons score (31 ± 19 preoperatively vs. 70 ± 25 postoperatively, P < .001), and average active forward elevation (71° ± 41° preoperatively vs. 128° ± 28° postoperatively, P < .001) were noted. Coronal-plane radiographic correction was 29° ± 12° as measured with the reverse shoulder arthroplasty angle (P < .001) and 14° ± 11° as measured with the β angle (P < .001). Postoperatively, of 17 patients with a minimum 1-year radiographic follow-up, 14 (82%) had complete radiographic incorporation of the graft. Acromial fracture nonunions developed in 2 patients and loosening and migration of the baseplate were found in 2 patients, although no patients elected to undergo further surgery., Conclusions: RTSA with allograft reconstruction of severe glenoid defects allows restoration of glenoid anatomy and leads to high rates of bony incorporation with low rates of glenoid loosening or requirement for revision. Structural allograft is an excellent alternative to autograft in revision RTSA to avoid graft-site morbidity., (Copyright © 2019 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.)

Background: The purpose of this study was to determine whether preoperative skin preparation with hydrogen peroxide reduces intraoperative culture positivity for Cutibacterium acnes in shoulder arthroplasty., Methods: This was a prospective, controlled, parallel/noncrossover, nonrandomized, single-blinded trial registered at clinicaltrials.gov. We included a consecutive series of patients scheduled to undergo primary anatomic or reverse total shoulder arthroplasty. The first group of patients underwent a standard skin preparation and the second group underwent the same preparation with the addition of hydrogen peroxide. We then took skin, dermis, glenohumeral joint, and air (negative control) aerobic and anaerobic culture swabs. We blinded the laboratory analyzing the samples. An a priori power analysis determined that 56 patients would be needed to see a 50% reduction in culture positivity rates. We also conducted a post hoc gender-stratified analysis., Results: Between January 2017 and October 2018, the authors performed 124 primary shoulder arthroplasties, of which we included 65 and collected samples on 61. There were no demographic differences. There were fewer patients within the peroxide group with triple-positive cultures (skin, dermis, and joint) (0% vs. 19%, P = .024) and positive cultures from the joint (10% vs. 35%, P = .031). In our subgroup analysis, these differences were only significant in males. The vast majority of positive cultures were with C. acnes., Conclusion: Although larger, randomized studies are needed, adding hydrogen peroxide to the preoperative skin preparation may be a low-cost, low-risk method to reduce deep tissue contamination with C. acnes, particularly within males., (Copyright © 2019 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.)

Background: It remains unclear whether changes in scapular rotation influence the surgeon's ability to achieve resting radiographic neutral or inferior baseplate tilt at final follow-up. The purposes of this study were (1) to determine whether reverse total shoulder arthroplasty (RTSA) changes the resting scapular rotation, (2) to determine the association between glenoid inclination with respect to the scapula (β angle) and resting scapular rotation, and (3) to determine the β angle threshold that will most likely lead to resting radiographic neutral or inferior baseplate tilt relative to the thorax., Methods: This was a retrospective radiographic study. Patients with adequate-quality standing anteroposterior and Grashey radiographs obtained preoperatively and after primary RTSA at a minimum of 1 year were included. Glenoid inclination (β angle) was measured between the supraspinatus fossa and the glenoid. Resting scapular rotation was measured between the supraspinatus fossa and a vertical line. Baseplate tilt was then calculated as the angle between the glenoid and a vertical line., Results: The study included 74 patients with a mean follow-up period of 3 years (range, 1-9 years). Scapular rotation changed 2° ± 12° (mean ± standard deviation) into upward rotation (P = .048). No association was found between the β angle and scapular rotation. In 71% of patients with a neutral or inferior baseplate tilt, a postoperative β angle greater than 85° was found., Conclusions: Resting radiographic scapular rotation changed 2° into upward rotation with RTSA and was not associated with the β angle. If the β angle is greater than 85°, resting radiographic baseplate tilt will most likely be inferior or neutral., (Copyright © 2019 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.)

Background: The purpose of this study was to identify factors associated with variation in direct costs with shoulder arthroplasty., Methods: This was a retrospective study of all shoulder arthroplasties performed at a single facility between July 1, 2011, and November 30, 2016. We collected patient factors, indications, procedure (including implant details), implant brand (A, B, and other), and complications. We collected direct costs over a 90-day period using a validated internal tool. We identified patient and procedure characteristics associated with costs using multivariable generalized linear models., Results: A total of 361 patients were included, 19% with revision arthroplasty procedures, 32% with anatomic total shoulder arthroplasties, and 66% with reverse total shoulder arthroplasties (RTSAs). Of total costs, 13% were operative facility utilization costs and 58% were operative supply costs. Factors associated with increased total cost included younger age (P = .002) and an indication for surgery of other, that is, not osteoarthritis, a failed arthroplasty, or the sequelae of a rotator cuff tear (P = .030). Factors associated with increased operative costs included younger age (P = .002), use of an RTSA (P < .001), use of a bone graft (P < .001), implant brand B (P = .098), implant brands other than A and B (P = .04), the sequelae of a rotator cuff tear as an indication for surgery (P = .041), or an indication for surgery of other (P = .007)., Conclusion: Most short-term (90-day) costs with shoulder arthroplasty are operative costs. Nonmodified factors associated with increased cost included younger age and less common indications for surgery, whereas potentially modifiable factors included the intraoperative use of a bone graft, implant brand, and RTSA use., (Copyright © 2018 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.)

Background: Although scapular morphology contributes to glenohumeral osteoarthritis and rotator cuff disease, its role in traumatic glenohumeral instability remains unknown. We hypothesized that coracoacromial and glenoid morphology would differ between healthy subjects and patients with recurrent traumatic anterior shoulder instability., Methods: Computed tomography scans of 31 cadaveric control scapulae and 54 scapulae of patients with recurrent traumatic anterior shoulder instability and Hill-Sachs lesions were 3-dimensionally reconstructed. Statistical shape modeling identified the modes of variation between the scapulae of both groups. Corresponding measurements quantified these modes in relation to the glenoid center (linear offset measures), defined by the best-fit circle of the inferior glenoid, or the glenoid center plane (angles), which bisects the glenoid longitudinally. Distances were normalized for glenoid size., Results: Compared with controls, the unstable coracoids were shorter (P = .004), with a more superior and medial offset of the tip (mean difference [MD], 7 and 3 mm, respectively; P < .001) and an origin closer to the 12-o'clock position (MD, 6°; P < .001). The unstable scapular spines originated closer to the 9-o'clock position (MD, 4°; P = .012), and the unstable acromions were more vertically oriented (MD, 6°; P < .001). The unstable glenoids had an increased height-width index (MD, 0.04; P = .021), had a flatter anterior-posterior radius of curvature (MD, 77 mm; P < .001), and were more anteriorly tilted (MD, 5°; P = .005)., Conclusions: Coracoacromial and glenoid anatomy differs between individuals with and without recurrent traumatic anterior shoulder instability. This pathologic anatomy is not addressed by current soft-tissue stabilization procedures and may contribute to instability recurrence., (Copyright © 2019 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.)

Background: Rotator cuff muscle volume is associated with outcomes after cuff repair and total shoulder arthroplasty. Muscle area on select magnetic resonance imaging (MRI) slices has been shown to be a surrogate for muscle volume. The purpose of this study was to determine whether computed tomography (CT) provides an equivalent measurement of cuff muscle area to a previously validated MRI measurement., Methods: We included 30 patients before they were undergoing total shoulder arthroplasty with both preoperative CT and MRI scans performed within 30 days of one another at 1 institution using a consistent protocol. We reoriented CT sagittal and MRI sagittal T1 series orthogonal to the scapular plane. On both CT and MRI scans, we measured the area of the supraspinatus, infraspinatus-teres minor, and subscapularis on 2 standardized slices as previously described. We calculated intraclass correlation coefficients and mean differences., Results: For the 30 subjects included, when MRI and CT were compared, the mean intraclass correlation coefficients were 0.989 (95% confidence interval [CI], 0.976-0.995) for the supraspinatus, 0.978 (95% CI, 0.954-0.989) for the infraspinatus-teres minor, and 0.977 (95% CI, 0.952-0.989) for the subscapularis. The mean differences were 0.2 cm 2 (95% CI, 0.0-0.4 cm 2 ) for the supraspinatus (P = .052), 0.8 cm 2 (95% CI, 0.1-1.4 cm 2 ) for the infraspinatus-teres minor (P = .029), and -0.3 cm 2 (95% CI, -1.2 to 0.5 cm 2 ) for the subscapularis (P = .407)., Conclusion: CT provides nearly equivalent measures of cuff muscle area to an MRI technique with previously validated reliability and accuracy. While CT underestimates the infraspinatus area as compared with MRI, the difference is less than 1 cm 2 and thus likely clinically insignificant., (Copyright © 2018 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.)

Background: The objectives of this study were to determine whether glenoid inclination (1) could be measured accurately on magnetic resonance imaging (MRI) using computed tomography (CT) as a gold standard, (2) could be measured reliably on MRI, and (3) whether it differed between patients with rotator cuff tears and age-matched controls without evidence of rotator cuff tears or glenohumeral osteoarthritis., Methods: In this comparative retrospective radiographic study, we measured glenoid inclination on T1 coronal MRI corrected into the plane of the scapula. We determined accuracy by comparison with CT and inter-rater reliability. We compared glenoid inclination between patients with full-thickness rotator cuff tears and patients aged >50 years without evidence of a rotator cuff tear or glenohumeral arthritis. An a priori power analysis determined adequate power to detect a 2° difference in glenoid inclination., Results: (1) In a validation cohort of 37 patients with MRI and CT, the intraclass correlation coefficient was 0.877, with a mean difference of 0° (95% confidence interval, -1° to 1°). (2) For MRI inclination, the inter-rater intraclass correlation coefficient was 0.911. (3) Superior glenoid inclination was 2° higher (range, 1°-4°, P < .001) in the rotator cuff tear group of 192 patients than in the control cohort of 107 patients., Conclusions: Glenoid inclination can be accurately and reliably measured on MRI. Although superior glenoid inclination is statistically greater in those with rotator cuff tears than in patients of similar age without rotator cuff tears or glenohumeral arthritis, the difference is likely below clinical significance., (Copyright © 2018 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.)

Background: The purpose of this study was to determine the effect of humeral articular component positioning on changes in patient-reported outcomes after anatomic total shoulder arthroplasty., Methods: This was a retrospective series of consecutive patients at 2 high-volume referral centers. The study included patients with (1) a preoperative and postoperative radiograph demonstrating a perfect or nearly perfect profile of the humerus and implant and (2) Simple Shoulder Test, visual analog scale for pain, and American Society of Shoulder and Elbow Surgeons (ASES) Standardized Shoulder Assessment scores preoperatively and at greater than 2 years postoperatively. Head height, head diameter, tuberosity-to-head height distance, inclination, and medial offset of the center of rotation (COR) were measured preoperatively and postoperatively. Distance and direction from the ideal COR to the reconstructed center of rotation was measured. Measurements were correlated with improvement in functional outcomes., Results: The study included 95 patients, aged 66 ± 9 years, with a mean follow-up of 4.3 ± 1.7 years. An a priori power analysis suggested that a sample size of 95 patients provided 80% power to detect correlations of R 2  = 0.07. The COR shift was >2 mm in 62% of patients and >4 mm 15%. Thirty-two percent had a change of ASES of <21 points. On multivariate analysis, there were no significant associations between any change in measured prosthetic radiographic parameters and changes in the visual analog scale, Simple Shoulder Test, or ASES scores (P > .05)., Conclusion: In this retrospective analysis of total shoulder arthroplasty in which most components were well positioned, humeral component positioning did not associate with change in postoperative outcomes. These findings should be prospectively confirmed., (Copyright © 2017 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.)

Background: This study evaluated the psychometric properties of the Patient-Reported Outcomes Measurement Information System (PROMIS) Physical Function (PF) instrument administered through computerized adaptive testing (CAT) compared with the traditional full-length Disabilities of the Arm, Shoulder and Hand (DASH)., Methods: The PROMIS PF CAT and the DASH were administered to 1759 patients seeking care for elbow conditions. This study used Rasch partial credit modeling to analyze the instruments with item fit, internal reliability, response category thresholds, dimensionality, local independence, gender differential item functioning, and floor and ceiling effects., Results: The PROMIS PF CAT and DASH had satisfactory item fit for all but 1 item on both measures. Internal reliabilities were high for both measures. Two items on the DASH and 4 items on the PF CAT showed nonordered category thresholds. Unidimensionality was adequate, and local independence was supported for both instruments. Gender bias was found for 4 items on the PF CAT and 12 items on the DASH. Both measures had adequate instrument targeting and satisfactory floor and ceiling effects., Conclusion: The PROMIS PF CAT and the DASH both showed sufficient unidimensionality, good item fit, and good local independence with the exception of high levels of gender item bias, particularly for the DASH. Further scale evaluation should address item bias and item response categories for these instruments. Overall, the PROMIS PF CAT is an effective outcome instrument to measure function in patients with elbow disorders that requires significantly fewer questions than the DASH., (Copyright © 2017 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.)

Background: Very limited information exists about factors affecting direct clinical costs of rotator cuff repair surgery. The purpose of this study was to determine the direct cost of outpatient arthroscopic rotator cuff repair surgery using a unique value-driven outcomes tool and to identify patient- and treatment-related variables affecting cost., Methods: Cost data were derived for arthroscopic rotator cuff repairs performed by 3 surgeons from March 2014 to June 2015 using the value-driven outcomes tool. Costs included overall total direct cost, which included facility utilization costs, medication costs, supply costs, and other ancillary costs. Univariate and multivariate regressions were performed to determine the effect of various patient-related and surgical-related factors on costs., Results: There were 170 arthroscopic rotator cuff repairs performed during the study period. Multivariate analysis showed significant correlations between higher total direct cost and the presence of a subscapularis repair being performed (P = .015) and total number of anchors used (P < .0001). Higher body mass index, severe systemic illness, 1 of the 3 surgeons, biceps tenodesis using an anchor, and total sum of anchors were correlated with higher facility utilization costs (P < .04). Severe systemic illness, addition of a subscapularis repair, 1 of the 3 surgeons, and additional subacromial decompression were correlated with higher pharmacy costs (P < .006). The addition of a subscapularis repair, total sum of anchors, and severe muscle changes to the supraspinatus were correlated with higher supply costs (P < .015)., Conclusions: From a direct cost perspective, implementation of strategies to reduce overall costs should focus on reducing overall anchor quantity or price., (Copyright © 2017 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.)

Background: Large glenoid bone defects in the setting of glenohumeral arthritis can present a challenge to the shoulder arthroplasty surgeon. The results of large structural autografting at the time of reverse total shoulder arthroplasty (RTSA) are relatively unknown., Methods: This retrospective case series describes the clinical and radiographic results of large structural autografting from the humeral head to the glenoid during primary RTSA., Results: Of 17 patients who met inclusion criteria, 14 (82% follow-up) were evaluated postoperatively at a mean of 2.6 years (range, 2.0-5.4 years). Mean inclination correction was 19° ± 12° (range, 3°-35°). Complications occurred in 3 patients, including 1 transient brachial plexus palsy, 1 loose baseplate, and 1 dislocation treated with closed reduction. Radiographic images showed 100% of grafts incorporated. Active forward elevation improved from 80° ± 40° to 130° ± 49° (P = .028). The visual analog scale score for pain improved from 8.1 ± 1.3 to 2.5 ± 3.1 (P = .005). The Simple Shoulder Test improved from 1.8 ± 1.1 to 6.5 ± 4 (P = .012). The American Shoulder and Elbow Surgeons score improved from 22 ± 10 to 66 ± 25 (P = .012). All patients (100%) were satisfied, and all patients (93%) but 1 stated that they would undergo the procedure again if given the chance., Conclusions: RTSA incorporating structural grafting of the glenoid with humeral head autograft results in significant improvements in active forward elevation, pain, and function, with a low complication rate. This technique can reliably be used to achieve correction of large (up to 35°) glenoid defects with a 93% chance of baseplate survival and a 100% chance of graft incorporation in the short-term., (Copyright © 2017 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.)

Background: Assessment of glenohumeral subluxation is essential in preoperative planning of total shoulder arthroplasty. The purpose of this study was to evaluate a 3-dimensional (3D) glenohumeral subluxation index (GHSI) in shoulders with primary osteoarthritis (OA) and its relationship with morbid glenoid retroversion., Methods: The 3D computed tomography reconstructions of 120 healthy shoulders and 110 shoulders with primary glenohumeral arthritis (OA group), classified according to Walch's glenoid morphology, were analyzed. The 3D GHSI was assessed by measuring posterior decentering of the humeral head in relation to the native glenoid in each subject, and its correlation to morbid glenoid version was calculated., Results: The reproducible 3D GHSI (intraclass correlation coefficients ≥ 0.842) showed a posterior decentering of the humeral head in the OA population and in each type of glenoid morphology (P ≤ .005). A moderate correlation was observed in the OA group (r = -0.542; P < .001), but weak linear relationships were found for different glenoid morphology types (r between 0.041 and -0.307). Type A shoulders (r = -0.375; P = .006) correlated better than type B shoulders (r =  -0.217; P = .104). After shoulders were subcategorized according to a threshold for 3D subluxation, the posteriorly subluxated group increased its correlation (r = -0.438; P < .001), whereas the centered shoulders still exhibited no relationship (r = -0.192; P = .329)., Conclusions: Posterior humeral head decentering in relation to the native glenoid is present in each glenoid morphology type. Grouping measures according to morphology type and 3D subluxation showed at best moderate correlations between morbid version and 3D GHSI., (Copyright © 2017 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.)

Background: The diagnosis of infection after shoulder arthroplasty can be challenging. The current study evaluated the utility of a prerevision biopsy sample in predicting positive cultures or a final diagnosis of infection in the setting of an "at-risk" failed shoulder arthroplasty., Methods: The study reviewed 77 patients with no history of infection undergoing revision shoulder arthroplasty by a single surgeon between June 2010 and July 2015. All patients with a C-reactive protein and erythrocyte sedimentation rate within normal reference ranges and no fluid on aspirate, or an abnormal value for the erythrocyte sedimentation rate or C-reactive protein, or both, and no growth on aspirate, underwent a prerevision biopsy because they were considered "at-risk" for infection. Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were calculated to evaluate the utility of biopsy specimens to predict positive cultures as well as a final determination of infection., Results: A prerevision biopsy was performed in 17 patients with a failed arthroplasty. The sensitivity, specificity, PPV, and NPV, for a positive prerevision biopsy sample to predict a positive final culture were 0.75, 0.6, 0.82, and 0.5, respectively. The sensitivity, specificity, PPV, and NPV for an infection defined by a prerevision biopsy sample to predict an infection defined by the combined final revision and biopsy cultures were 0.9, 0.86, 0.9, and 0.86, respectively., Conclusions: The ability for prerevision biopsy specimens of failed arthroplasties to predict the presence of bacteria at the time of revision surgery is high, although lower than previously reported. If biopsy results are used to define and predict a diagnosis of infection, the sensitivity, specificity, PPV, and NPV all significantly improve., (Copyright © 2017 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.)

Background: The best chance that a shoulder arthroplasty will restore motion and muscle balance across the glenohumeral joint is by closely replicating natural articular morphology. Defining the humeral osteotomy plane along clear landmarks at the anatomic neck is critical. We hypothesized that a new osteotomy, based on alternative landmarks on the anatomic neck, would restore 3-dimensional humeral head morphology more reliably than the traditional osteotomy., Methods: The anatomic neck was digitized in 30 human cadaver shoulders and compared with its 3-dimensional computed tomography reconstruction. Two different osteotomy techniques were virtually performed: the traditional, following the anterosuperior anatomic neck; and a new technique, defined by the inferoanterior anatomic neck. The length-width difference and orientation (retroversion, inclination) of the resection area were compared between the techniques and with native anatomy., Results: Length-width difference of the anterosuperior resection area was higher than in the inferoanterior osteotomy (6 ± 2 mm vs. 3 ± 1 mm; P < .001). Retroversion of the anterosuperior resection plane was higher than the native head (50° ± 12° vs. 37° ± 11°; P < .001), whereas retroversion after the inferoanterior osteotomy (32° ± 12°) did not differ from native (P = .057). Inclination differed after the anterosuperior osteotomy (129° ± 5°) and the inferoanterior osteotomy (127° ± 4°) compared with the native head (134° ± 4°; P ≤ .001)., Conclusion: The inferoanterior referenced osteotomy generated a more circular resection area, matching the native humeral head retroversion more closely than in the anterosuperior technique. This study suggests that in shoulder arthroplasty, the humeral resection level should be referenced at the inferoanterior rather than the anterosuperior anatomic neck. Further studies should investigate the biomechanical effects of this alternative resection plane., (Copyright © 2017 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.)

Background: Minimal clinically important differences (MCIDs) for the American Shoulder and Elbow Surgeons (ASES) score, the Simple Shoulder Test (SST), and a visual analog scale (VAS) measuring pain have not been previously described using an anchor-based method after shoulder arthroplasty. The purpose of this study was to determine the MCIDs for these measures after shoulder arthroplasty for glenohumeral arthritis or advanced rotator cuff disease., Methods: Primary anatomic total shoulder arthroplasty (TSA), primary reverse TSA, or hemiarthroplasty was performed in 326 patients by 1 of 5 shoulder and elbow surgeons. The SST score, ASES score, and VAS pain score were collected preoperatively and at a minimum of 2 years postoperatively (mean, 3.5 years). The MCIDs were calculated for the ASES score, SST score, and VAS pain score using an anchor-based method., Results: The MCIDs for the ASES score, SST score, and VAS pain score were 20.9 (P < .001), 2.4 (P < .0001), and 1.4 (P = .0158), respectively. Duration of follow-up and type of arthroplasty (anatomic TSA vs reverse TSA) did not have a significant effect on the MCIDs (P > .1) except shorter follow-up correlated with a larger MCID for the ASES score (P = .0081). Younger age correlated with larger MCIDs for all scores (P < .024). Female sex correlated with larger MCIDs for the VAS pain score (P = .123) and ASES score (P = .05)., Conclusions: Patients treated with a shoulder arthroplasty require a 1.4-point improvement in the VAS pain score, a 2.4-point improvement in the SST score, and a 21-point improvement in the ASES score to achieve a minimal clinical importance difference from the procedure., (Copyright © 2017 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.)

Background: A familial and genetic predisposition for the development of rotator cuff tearing has been identified. The purpose of this study was to determine if a familial predisposition exists for healing after rotator cuff repair and if the reported significant association with a single-nucleotide polymorphism (SNP) in the ESRRB gene is present in patients who fail to heal., Materials and Methods: The study recruited 72 patients undergoing arthroscopic rotator cuff repair for a full-thickness posterosuperior tear. Magnetic resonance imaging studies were performed at a minimum of 1 year postoperatively (average, 2.6 years). Healing failures were classified as lateral or medial. Self-reported family history of rotator cuff tearing data and genome-wide genotypes were available. Characteristics of cases with and without a family history of rotator cuff tearing were compared, and a comparison of the frequency of SNP 1758384 (in ESRRB) was performed between patients who healed and those who failed to heal., Results: Of the rotator cuff repairs, 42% failed to heal; 42% of patients reported a family history of rotator cuff tear. Multivariate regression analysis showed a significant association between familiality and overall healing failure (medial and lateral failures) (P = .036) and lateral failures independently (P = .006). An increased risk for the presence of a rare allele for SNP rs17583842 was present in lateral failures compared with those that healed (P = .005)., Conclusions: Individuals with a family history of rotator cuff tearing were more likely to have repair failures. Significant association of a SNP variant in the ESRRB gene was also observed with lateral failure., (Copyright © 2016 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.)

Background: The precise etiology of rotator cuff disease is unknown, but prior evidence suggests a role for genetic factors. Limited data exist identifying specific genes associated with rotator cuff tearing. The purpose of this study was to identify specific genes or genetic variants associated with rotator cuff tearing by a genome-wide association study with an independent set of rotator cuff tear cases., Materials and Methods: A set of 311 full-thickness rotator cuff tear cases genotyped on the Illumina 5M single-nucleotide polymorphism (SNP) platform were used in a genome-wide association study with 2641 genetically matched white population controls available from the Illumina iControls database. Tests of association were performed with GEMMA software at 257,558 SNPs that compose the intersection of Illumina SNP platforms and that passed general quality control metrics. SNPs were considered significant if P < 1.94 × 10(-7) (Bonferroni correction: 0.05/257,558)., Results: Tests of association revealed 2 significantly associated SNPs, one occurring in SAP30BP (rs820218; P = 3.8E-9) on chromosome 17q25 and another occurring in SASH1 (rs12527089; P = 1.9E-7) on chromosome 6q24., Conclusions: This study represents the first attempt to identify genetic factors influencing rotator cuff tearing by a genome-wide association study using a dense/complete set of SNPs. Two SNPs were significantly associated with rotator cuff tearing, residing in SAP30BP on chromosome 17 and SASH1 on chromosome 6. Both genes are associated with the cellular process of apoptosis. Identification of potential genes or genetic variants associated with rotator cuff tearing may help in identifying individuals at risk for the development of rotator cuff tearing., (Copyright © 2016 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.)

Background: The Patient-Reported Outcomes Measurement Information System (PROMIS) Physical Function Computerized Adaptive Test (PF CAT) is a newly developed patient-reported outcome instrument designed by the National Institutes of Health to measure generalized physical function. However, the measurement properties of the PF CAT have not been compared with established shoulder-specific patient-reported outcomes., Methods: Patients with clinical diagnosis of rotator cuff disease completed the American Shoulder and Elbow Surgeons (ASES) score, Simple Shoulder Test (SST), and PF CAT. Responses to each of the 3 instruments were statistically analyzed with a Rasch partial credit model. Associations between instruments, convergent validity, item and person reliability, ceiling and floor effects, dimensionality, and survey length were determined., Results: Responses from 187 patients were analyzed. The PF CAT required fewer questions than the ASES or SST (PF CAT, 4.3; ASES, 11; SST, 12). Correlation between all instruments was moderately high. Item reliability was excellent for all instruments, but person reliability of the PF CAT was superior (0.93, excellent) to the SST (0.71, moderate) and ASES (0.48, fair). Ceiling effects were similar among all instruments (PF CAT, 0.53%; SST, 6.1%; ASES, 2.3%). Floor effects were found in 21% of respondents to the SST but in only 3.2% of PF CAT and 2.3% of ASES respondents., Conclusion: The measurement properties of the PROMIS PF CAT compared favorably with the ASES and SST despite requiring fewer questions to complete. The PROMIS PF CAT had improved person reliability compared with the ASES score and fewer floor effects compared with the SST., (Copyright © 2015 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.)

Background: Accurate assessment of the critical shoulder angle (CSA) is important in clinical evaluation of degenerative rotator cuff tears. This study analyzed the influence of radiographic viewing perspective on the CSA, developed a classification system to identify malpositioned radiographs, and assessed the relationship between the CSA and demographic factors., Methods: Glenoid height, width, and retroversion were measured on 3-dimensional computed tomography reconstructions of 68 cadaver scapulae. A digitally reconstructed radiograph was aligned perpendicular to the scapular plane, and retroversion was corrected to obtain a true anteroposterior (AP) view. In 10 scapulae, incremental anteversion/retroversion and flexion/extension views were generated. The CSA was measured, and a clinically applicable classification system was developed to detect views with >2° change in CSA vs. true AP view., Results: The average CSA was 33° ± 4°. Intraobserver and interobserver reliability was high (intraclass correlation coefficient ≥ 0.81) but decreased with increasing viewing angle. Views beyond 5° anteversion, 8° retroversion, 15° flexion, and 26° extension resulted in >2° deviation of the CSA compared with the true AP view. The classification system was capable of detecting aberrant viewing perspectives with sensitivity of 95% and specificity of 53%. Correlations between glenoid size and CSA were small (R ≤ 0.3), and CSA did not vary by gender (P = .426) or side (P = .821)., Conclusions: The CSA was most susceptible to malposition in anteversion/retroversion. Deviations as little as 5° in anteversion resulted in a CSA >2° from true AP view. A new classification system refines the ability to collect true AP radiographs of the scapula. The CSA was unaffected by demographic factors., (Copyright © 2015 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.)

Background: Various reverse total shoulder arthroplasty (rTSA) implant options are available for the humeral and glenosphere components. This study used a cadaveric biomechanical shoulder simulator to evaluate how hardware configurations in 2 common rTSA systems affect (1) abduction/adduction range of motion (ROM), (2) rotational ROM, and (3) forces to elevate the arm., Methods: Seven pairs of shoulders were tested on a biomechanical shoulder simulator before and after rTSA implantation. The Aequalis Reverse Shoulder (Tornier, Edina, MN, USA) and the Reverse Shoulder Prosthesis (RSP; DJO Surgical, Austin, TX, USA) were implanted in opposing shoulders. Aequalis implant options included humeral polymer insert thickness and eccentricity and glenosphere tilt. RSP implant options included glenosphere diameter and lateralization, humeral shell offset, and polymer insert depth., Results: Both the RSP and Aequalis shifted the center of rotation inferior and medially compared with native shoulders (P < .001). Increased Aequalis insert thickness reduced adduction (P < .003) and internal/external (P < .028) passive ROM. The 10° inferiorly tilted glenosphere increased deltoid abduction forces (P < .032). In the RSP, smaller glenosphere diameter (P < .012), a semiconstrained humeral insert (P < .023), and a neutral humeral shell offset (P < .002) all decreased adduction deficit, whereas lateral glenosphere offset increased passive abduction ROM (P < .028). Increased humeral shell offset decreased passive internal/external rotation ROM (P < .050)., Discussion: Hardware configurations in rTSA have different effects on passive ROM and deltoid forces required for abduction. Identifying these changes may guide surgical decision making during rTSA placement., (Copyright © 2015 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.)

Background: The precise etiology of rotator cuff disease is unknown, but prior evidence suggests a role for genetic factors. Variants of estrogen-related receptor-β (ESRRB) have been previously associated with rotator cuff disease. The purpose of the present study was to confirm the association between multiple candidate genes, including ESRRB, and rotator cuff disease in an independent set of patients with rotator cuff tear., Materials and Methods: The Illumina 5M (Illumina Inc, San Diego, CA, USA) single nucleotide polymorphism (SNP) platform was used to genotype 175 patients with rotator cuff tear. Genotypes were used to select a set of 2595 genetically matched Caucasian controls available from the Illumina iControls database. Tests of association were performed with Genome-wide Efficient Mixed Model Association (GEMMA) software at 69 SNPs that fell within 20 kb of 6 candidate genes (DEFB1, DENND2C, ESRRB, FGF3, FGF10, and FGFR1)., Results: Tests of association revealed 1 significantly associated SNP occurring in ESRRB (rs17583842; P = 4.4E-4). Another SNP within ESRRB (rs7157192) had a nominal P value of 7.8E-3. FastPHASE software estimated 2 frequent haplotypes among 54 individuals who carried both risk alleles at these 2 SNPs. The first haplotype had a frequency of 13.9% (n = 15) in risk-allele carriers and only 2.2% in controls (odds ratio, 6.9; 95% confidence interval, 3.9-2.2). The second haplotype had a frequency of 12.9% in risk-allele carriers and only 2.7% in controls (odds ratio, 5.3; 95% confidence interval, 3.0-9.5)., Conclusions: The significant association and the presence of high-risk haplotypes identified in the ESRRB gene confirm the association of variants in ESRRB and rotator cuff disease., (Copyright © 2015 Journal of Shoulder and Elbow Surgery Board of Trustees. All rights reserved.)

Background: Numerous studies have examined the biomechanics of isolated variables in reverse total shoulder arthroplasty. This study directly compared the composite performance of two reverse total shoulder arthroplasty systems; each system was designed around either a medialized or a lateralized glenohumeral center of rotation., Methods: Seven pairs of shoulders were tested on a biomechanical simulator. Center of rotation, position of the humerus, passive and active range of motion, and force to abduct the arm were quantified. Native arms were tested, implanted with a Tornier Aequalis or DJO Surgical Reverse Shoulder Prosthesis (RSP), and then retested. Differences from the native state were then documented., Results: Both systems shifted the center of rotation medially and inferiorly relative to native. Medial shifts were greater in the Aequalis implant (P < .037). All humeri shifted inferior compared with native but moved medially with the Aequalis (P < .001). Peak passive abduction, internal rotation, and external rotation did not differ between systems (P > .05). Both reverse total shoulder arthroplasty systems exhibited adduction deficits, but the RSP implant deficit was smaller (P = .046 between implants). Both systems reduced forces to abduct the arm compared with native, although the Aequalis required more force to initiate motion from the resting position (P = .022)., Conclusion: Given the differences in system designs and configurations, outcome variables were generally comparable. The RSP implant allowed slightly more adduction, had a more lateralized humeral position, and required less force to initiate elevation. These factors may play roles in limiting scapular notching, improving active external rotation by normalizing the residual rotator cuff length, and limiting excessive stress on the deltoid., (Copyright © 2014 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Mosby, Inc. All rights reserved.)

Background: Subpectoral biceps tenodesis has been reliably used to treat a variety of biceps tendon pathologies. Interference screws have been shown to have superior biomechanical properties compared to suture anchors; although, only single anchor constructs have been evaluated in the subpectoral region. The purpose of this study was to compare interference screw fixation with a suture anchor construct, using 2 anchors for a subpectoral tenodesis., Methods: A subpectoral biceps tenodesis was performed using either an interference screw (8 × 12 mm; Arthrex) or 2 suture anchors (Mitek G4) with #2 FiberWire (Arthrex) in a Krackow and Bunnell configuration in seven pairs of human cadavers. The humerus was inverted in an Instron and the biceps tendon was loaded vertically. Displacement driven cyclic loading was performed followed by failure loading., Results: Suture anchor constructs had lower stiffness upon initial loading (P = .013). After 100 cycles, the stiffness of the suture anchor construct "softened" (decreased 9%, P < .001), whereas the screw construct was unchanged (0.4%, P = .078). Suture anchors had significantly higher ultimate failure strain than the screws (P = .003), but ultimate failure loads were similar between constructs: 280 ± 95 N (screw) vs 310 ± 91 N (anchors) (P = .438)., Conclusion: The interference screw was significantly stiffer than the suture anchor construct. Ultimate failure loads were similar between constructs, unlike previous reports indicating interference screws had higher ultimate failure loads compared to suture anchors. Neither construct was superior with regards to stress; although, suture anchors could withstand greater elongation prior to failure., (Copyright © 2013 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Mosby, Inc. All rights reserved.)

Background: Interscalene brachial plexus block (ISBPB) provides excellent analgesia after rotator cuff surgery but is associated with diaphragm dysfunction. In this study, ISBPB with 20 mL of 0.125% or 0.25% bupivacaine were compared to assess the effect on diaphragm function, oxygen saturation, pain control, opioid requirements, and patient satisfaction., Materials and Methods: In this prospective, randomized, double-blind study, 30 adults undergoing outpatient arthroscopic rotator cuff repair were enrolled to receive ultrasound-guided interscalene brachial plexus catheter placement with 20 mL of 0.125% (n = 15) or 0.25% bupivacaine (n = 15). Diaphragm function and oxygen saturation were assessed before ISBPB placement and on discharge from the postanesthesia care unit. Postoperative pain scores, opioid requirements, and patient satisfaction were compared., Results: Diaphragm function and oxygen saturation were superior in the low concentration group. Absent or paradoxic motion of the diaphragm was present in 78% of the 0.25% group compared with 21% of patients in the 0.125% group (P = .008). Oxygen saturation decreased 4.3% in the 0.25% group compared with a decrease of 2.6% in the 0.125% group (P = .04). Pain scores averaged 1 of 10 in the 0.25% group and 0 of 10 in the 0.125% group (P = .02). Opioid requirements and patient satisfaction were not different between the two groups., Conclusions: In this randomized, double-blind comparison of ISBPB performed with 20 mL of 0.125% or 0.25% bupivacaine, diaphragm function and oxygen saturation were superior in patients treated with more dilute bupivacaine. Furthermore, there were no clinically significant differences in pain scores, and no statistically significant differences in opioid requirements and patient satisfaction., (Copyright © 2013 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Mosby, Inc. All rights reserved.)

Background: Studies have reported high rates of transfusion in shoulder arthroplasty. This study was conducted to evaluate the rate of transfusion at our institution, to confirm reported risk factors for transfusion, and to look for changes over time.We hypothesized that transfusion rates associated with shoulder arthroplasty at our institution are lower than those recently reported and that the incidence of transfusion is higher in individuals with low preoperative hemoglobin, with revision arthroplasty, and in older individuals., Materials and Methods: A retrospective review of 366 shoulder arthroplasties (323 patients) was performed. This included total shoulder arthroplasties, hemiarthroplasties, revision arthroplasties, and reverse total shoulder arthroplasties. Logistic regression analysis evaluated the association of clinical variables with transfusion. Early (1996-2005) and late (2006-2009) groups were compared to evaluate changes in demographics and transfusion rates over time., Results: The overall transfusion rate was 7.4% (27 of 339). Predictors of transfusion were higher intraoperative blood loss, low preoperative hemoglobin level, and humeral cement fixation. Procedure type was not predictive of transfusion. There was no difference in transfusion rates between the early and late groups, but the late group had an increased use of general anesthesia combined with a regional block, increased intraoperative blood loss, and increased use of sequential compression devices for venous thromboembolism prophylaxis., Conclusions: Lower preoperative hemoglobin, higher intraoperative blood loss, and humeral cement fixation were predictors of transfusion, but not female sex, increasing age, type of procedure, or comorbidities., (Copyright © 2013 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Mosby, Inc. All rights reserved.)