Background: Clavicle fractures are frequent (5-10% of all fractures) with midshaft fractures being the most common, accounting for up to 80% of all clavicle fractures. The best treatment option is still debated. Aim of this study was to evaluate the rate of scapular dyskinesis, clinical, functional, and radiological outcomes in patients treated surgically or conservatively for midshaft clavicle fractures.

Methods: This retrospective monocentric study included midshaft clavicle fracture patients (AO 15. A) treated operatively or conservatively from 2009 to 2022. Outcomes evaluated were scapular dyskinesis, Costant score, Disabilities of Arm, Shoulder, and Hand (DASH) score, radiological outcomes (nonunion and mal union rates), aesthetic and general satisfaction.

Results: 124 patients were included, 69 (55%) in the surgical group and 55 (45%) in the conservative group. Mean age was 54 ± 9 years and mean follow-up time was 8 ± 2 years. Scapular dyskinesis was present in 19.1% (13 / 69) patients treated surgically and 54.5% (30 / 55) patients treated conservatively (p < 0.05). The surgical group showed statistically better Constant score (p < 0.05) and radiological healing (p < 0.05). DASH score, aesthetic and general satisfaction were similar for both groups (p = n.s.).

Conclusions: Surgical intervention leads to better clinical and radiological outcomes compared to conservative treatment, reducing the risk of developing scapular dyskinesis, nonunion and mal union. While conservative treatment leads to satisfactory results and can be proposed to patients with lower functional demand or higher surgical risk, surgery provides the best results for the treatment of midshaft clavicle fractures.

Introduction: Clavicle fractures represent up to 10% of all fractures, affecting mainly a young population. Open reduction and internal plate fixation provide good results, but evidence on the best plate positioning is still unclear. Aim of this study was compare superior and antero-inferior plating positioning in the surgical treatment of displaced midshaft clavicle fractures.
Methods: Patients aged >18 years, treated surgically with plate fixation for a midshaft clavicle fracture from January 2010 to April 2021 were included. Shoulder function was evaluated with the use of Constant-Murley Score (CMS) and Disabilities of the Arm, Shoulder, and Hand (DASH) score. Return to sport, aesthetic satisfaction, operative time, radiological outcomes, rate of implant removal, and overall patient satisfaction were documented as well.
Results: 104 patients (51 superior, 53 antero-inferior plating) were included. At the time of the visit, mean follow-up time was 6.7±2.6 years. Mean CMS was 94.1±10.0 points in the superior plating group and 93.4±11.6 points in the antero-inferior plating group. DASH score: 4.6±11.0 superior, 5.1±10.5 antero-inferior. Return to sport: 8.2±2.9 superior, 8.2±3.0 antero-inferior. Aesthetic satisfaction: 8.9±1.6 superior, 8.8±2.1 antero-inferior. Overall satisfaction: 9.1±1.5 superior, 8.9±1.7 antero-inferior. The comparison between groups showed no statistically significant differences (p=n.s.) for all outcome measures. Operative time: 101.6±27.3 minutes superior, 113.0±31.6 minutes antero-inferior (p=0.05). Radiological follow-up documented one non-union and one mal-union in the antero-inferior plating group. Overall, 63 patients underwent plate removal: 58.8% in the superior plating group and 62.3% in the antero-inferior plating group (p=n.s.). Main reason for plate removal was pain/discomfort.
Conclusions: Both superior and antero-inferior plating provided excellent clinical, functional, and radiological results for the treatment of displaced midshaft clavicle fractures, without significant differences among groups. The superior plating group showed a statistically shorter operative time. High rate of re-interventions with implant removal was documented in both groups.

Introduction: Proximal humerus fractures are among the most common fractures in the geriatric population, associated with substantial morbidity, mortality, and economic burden. However, little is known about their economic impact on the working-age population. This retrospective study aimed to investigate the economic burden of proximal humerus fractures in the working population, stratified by age, sex, and occupational class.

Methods: Data were extracted from the SUVA register of professionally active patients with proximal humerus fractures between 2014 and 2022. All patients diagnosed with a proximal humerus fracture, as indicated by the ICD-10 WHO code S42.2, were included. Patients with incomplete data and less than 2 years follow-up were excluded. Patients were categorized by age (15-24, 25-34, 35-44, 45-54, 55-64), sex, and occupation using the ISCO classification according to the International Labour Organization. Return-to-work rates were assessed at 1, 3, 6 months, and 1, 2, 5 years post-trauma. The cost-weight is presented in Swiss francs (CHF).

Results: A total of 29'886 proximal humerus fractures were identified, predominantly in males (male-to-female ratio: 1.5:1). The 45-54 age group was most frequently affected, followed by the 55-64 age group. Occupational groups 2-4 (i.e. professionals, technicians and office workers) had the highest occurance. Group 8 (i.e. machine operators) incurred the highest cost weight (17'131 ± 45'089 CHF). Return-to-work rates were lower in the 55-64 age group, with only 80.5% returning to full employment compared to 92% in the 15-24 age group. Consequently, the cost-weight was significantly higher in the 55-64 age group.

Conclusion: Proximal humerus fractures impose a substantial economic burden on the working-age population, with significant variations by age, sex, and occupational class. Strategies to mitigate this burden should target high-risk groups, particularly older workers, to enhance return-to-work rates and reduce economic costs.

Importance
Internationally, the optimal treatment strategy of proximal humerus fractures remains much debated.

Objective
To investigate whether operative treatment of displaced proximal humerus fractures is superior to nonoperative treatment.

Design
A prospective natural experiment (prospective cohort study) based on geographical randomization and clinical equipoise.

Setting
An international multicenter cohort study in the Netherlands and Switzerland
Participants In total 226 patients with acute (< 3 weeks) displaced proximal humerus fractures presenting from July 2020 until March 2022 were included after expert panel evaluation based on clinical equipoise. Patients were followed up for one year, and 191 (84%) had complete follow-up data.

Interventions
Operative treatment included plate fixation, intramedullary nailing and reverse shoulder arthroplasty at the discretion of the treating surgeon. Nonoperative treatment was sling immobilization. All patients received standardized outpatient rehabilitation and physiotherapy.

Main outcomes and measures
The primary outcome was QuickDASH after one year. Secondary outcomes included QuickDASH at six weeks and EuroQoL5D (EQ5D), Subjective shoulder value (SSV), numeric rating scale for pain (NRS) at six weeks and one year.

Results
No difference in QuickDASH score after one year (16.3 vs. 17.5, p = 0.836) was found. At six weeks, operative treatment resulted in lower NRS (4.2 vs 3.0, p < 0.001), higher EQ5D (0.59 vs. 0.68, p = 0.015) and higher SSV (41.8 vs. 53.6, p=0.002). At one year operative treatment resulted in higher SSV (70.9 vs. 83.5, p < 0.001). Increase in SSV was similar between groups (29.1 vs. 29.9, p = 0.234) and EQ5D was comparable after one year (0.87 vs. 0.86, p = 0.980).

Conclusion and relevance
No differences were observed in functional outcomes after one year. However, operative treatment resulted in lower NRS and higher EQ5D at six weeks. The SSV was better for the operative group at both six weeks and one year. Therefore, operative treatment might be beneficial in the short term for selected patients.

Introduction
Reverse total shoulder arthroplasty (RTSA) is a well-established treatment option for complex proximal humerus fractures in elderly patients.
One important factor for good clinical outcomes is the healing of the greater tuberosity (GT). The purpose of this study was to compare the outcomes of patients receiving GT refixation with a so-called “cow hitch” (CH) suture cerclage fixation or with the recommended standard suture cerclage fixation technique at a minimum follow-up of 2 years.

Methods
A retrospective case-control study was performed with 20 patients who underwent RTSA with CH fixation of the GT compared to a control group including 51 patients after RTSA with the recommended standard suture cerclage fixation of the GT for the tested implant.
Radiological healing of the GT was defined as the primary outcome parameter and was assessed with standard radiographs at last follow up visit. Clinical outcome was assessed as the secondary outcome parameter and was measured with the absolute and relative Constant-Murley score (aCS and rCS), subjective shoulder value (SSV), range-of-motion (ROM) assessment and patient’s reported outcome satisfaction (PROM).

Results
The mean follow-up duration was 37 ± 16 months in the CH group and 35 ± 15 months in the control group (P = .95). The radiographic findings revealed a 95% healing rate of the GT in the CH group compared to 75% healing rate in the control group (P = .09). No secondary displacement of the GT was observed in the CH group compared to 8 cases (15%) in the control group (P = .1).

At the latest follow-up, the aCS was significantly higher in the CH group than in the control group (68 ± 12 points vs 62 ± 14 points) (P = .04). The rCS and SSV was comparable between the two groups (82 ± 13 % vs 82 ± 18% (P = .06) and 86 ± 11 % vs. 83 ± 18% (P = 1), respectively). The CH group showed significantly better external rotation compared to the control group (31 ± 15° vs 18 ± 16°) (P = .01). No significant differences were observed for flexion and abduction. PROMs were comparable between the two groups.

Conclusion
The use of CH suture cerclage for refixation of the GT in RTSA following complex proximal humerus fractures was noninferior to the standard suture cerclage in terms of radiographic outcomes and PROMs but showed better external rotation.

Fracture sequelae after failed operative treatment of proximal humerus fractures represents a very complex pathology of the shoulder joint and is often associated with adverse events and complications due to osseous defects, rotator cuff deficiency, numerous previous surgeries and stiffness. However, RSA is often the only therapeutic option left to improve patient satisfaction. Glenoid lateralization may improve pretensioning of the deltoid muscle and the residual rotator cuff and reduce scapular notching.
Aim of this study was to evaluate complications as well as clinical and radiological results of RSA fracture sequelae situations.

This retrospective study from prospective data included patients who underwent RSA after failed operative treatment of a proximal humerus fracture. Inclusion criteria was previous reconstructive surgical treatment and secondary RSA implantation with or without metallic glenoid augmentation at one of two institutions with a minimum two year follow-up examination. All adverse events were recorded in addition to Constant Score (CS) and Subjective Shoulder Value (SSV) and range of motion, as well as radiographic evaluation was included.

52 patients treated with RSA for fracture sequelae (female n=32, male n=20; Ø=66 years) were included. Adverse events resp. complications occurred in seven patients (reversible axillary palsy, instability, periprosthetic fracture, glenoid loosening), resulting in a complication rate of 13%, of which four (8%) led to revision). 16 patients were treated with metallic glenoid augmentation of the baseplate.
All patients treated for fracture sequelae improved statistically significant in CS, SSV (p < 0.01) and all planes of range of motion (p < 0.05) compared to baseline function.
Patients with glenoid lateralization showed superior flexion (p=0.04), abduction (p=0.03), external rotation (p=0.03) and significant lower rates of scapular notching (0% vs 16%).

RSA provides reliable clinical and radiographic results as a treatment option for patients with fracture sequelae. Since the rate of adverse events resp. complication leading to revision are similar in lateralized and non-lateralized designs we continue to use metallic glenoid augmentation in this specific patient cohort due to superior functionality after RSA.

ABSTRACT:
Introduction: Reverse shoulder arthroplasty (RSA) is becoming an increasingly common surgical treatment option for elderly patients with proximal humerus fractures. Given the high rate of osteoporotic fractures and the increased risk of intraoperative fractures and/or postoperative loosening of the stem in this patient population, the use of cement is the standard of care. However, the use of cement has been associated with some risks. We analyzed clinical and radiological data two years postoperatively in patients treated with uncemented humeral stems.
Methods: From January 2019 to February 2022, 133 proximal humerus fractures underwent RSA at our institution. In total, 54 shoulders (52 patients) were treated with the same uncemented system (Global Unite Reverse Fracture, DePuy Synthes, Warsaw, IN, USA) and tubercula refixation method. Clinical (e.g., range of motion, Constant Score - CS, American Shoulder and Elbow Score - ASES and subjective shoulder valued - SSV) and radiological (e.g., ingrowth of the tubercula, osteoporosis, stem loosening, notching) parameters were assessed two years after surgery. In addition to describing the entire cohort, we compared patient groups according to the pathologic deltoid tuberosity index (DTI).

Results: The mean age was 78.6 years (±8; range 61-95), 87% were female, and 69% were osteoporotic fractures. At the two-year follow-up, the median SSV was 90% (IQR 80-95), the median CS was 76.5 (IQR 72-81), and the median ASES was 89.9 (IQR 82-93). The median active forward flexion reached 140° (IQR120-160), the mean external rotation 30° (IQR 20-30), and the median active internal rotation was 6 (IQR 4-8) points. The greater tuberosity (GT) healing rate was 94.5%. Although the osteoporotic fractures occurred more often in older patients (mean 81 vs. 72 years), there was no significant difference in clinical outcomes between the osteoporotic and non-osteoporotic fractures. However, there was one case of aseptic stem loosening in the osteoporotic group.
Conclusion: Even in osteoporotic fractures, the use of the cementless stems to treat patients with proximal humerus fractures is a valuable option and is not associated with a higher complication rate. The reattachment technique of GT resulted in a high rate of ingrowth two years postoperatively.

Background: Glenoid component loosening remains a challenge in anatomic total shoulder arthroplasty (aTSA). This study evaluates the longevity of aTSA using the Eclipse humeral component and cemented polyethylene pegged glenoid (Arthrex, Naples, FL, USA), comparing outcomes and complications in primary versus secondary osteoarthritis.
Methods: 211 cases of stemless aTSA with a pegged glenoid were enrolled in our local registry. Between 01/2011 and 12/2016, 197 individuals who underwent primary aTSA using the described components were retrospectively evaluated grouped into primary (G1) or secondary osteoarthritis (G2), 14 patients treated for other conditions than osteoarthritis were excluded. Clinical and radiological assessments were conducted 2,5, and 10 years postoperatively or if the patient has presented himself due to complaints, including: Constant Score, DASH, SPADI, SSV, EQ-5D-5L ,Walch Classification, Critical Shoulder Angle, Lateral Acromion Index, Glenohumeral Distance, Glenoid Cementation, Component Loosening. We compared complications, revision rates and survival rates between groups.
Results: G1 (n=153) and G2 (n=44) had follow-up durations averaging 74.2±29.9 and 77.2±28.2 months (p=0.54). G1, older at inclusion (67±8 years) compared to G2 (59±10 years, p < 0.001), demonstrated a revision rate of 50%, as opposed to 55% in G2. G1 exhibited longer mean survival (77±30 months vs. 66±23 months, p=0.015). No significant differences were found between titanium coated vs standard humeral components in terms of survival rates (p=0.76). Key revision causes were glenoid loosening (G1:n=65;G2:n=21), periprosthetic fractures (G1:n=7;G2:n=2), and low-grade infections (G1:n=2;G2: n=1). Preoperative functional scores (Constant Score:G1=36±16,G2=34±17; qDASH, SPADI: both groups 42±20, 42±23 respectively) and radiologic parameters (CSA,LAI) were similar across groups. Operative time was shorter for Group 1 (99±22 minutes vs. 109±23 minutes, p=0.016). Postoperative radiologic and clinical assessments at 2, and 5 years revealed no significant differences (p > 0.05) in non-revised patients.
Conclusion: Both groups demonstrated alarmingly high revision rates with comparable follow-up. Primary osteoarthritis patients showed longer mean survival despite being older. Glenoid loosening was the predominant revision cause, underscoring the need for further research into glenoid failure mechanisms to enhance patient outcomes and implant longevity.

Introduction: Reverse shoulder arthroplasty (RSA) is widely considered the standard treatment for the majority of patients with cuff tear arthropathy, but cases with a combined loss of active elevation and external rotation (CLEER) due to insufficient infraspinatus and teres minor muscles are challenging. Since RSA alone may not adequately restore external rotation, a modified L’Episcopo procedure (latissimus dorsi and teres major transfer) may be advantageous. Our study aimed to assess patient outcomes after RSA and a modified L’Episcopo tendon transfer.

Methods: 21 consecutive patients undergoing RSA (Delta XtendTM, DePuy Synthes, Warsaw, IN, USA) with a modified L’Episcopo between January 2017 and January 2022 were prospectively enrolled. Standardized implantation and tendon transfer techniques were performed through a single deltopectoral approach. Demographic information and pre- and postoperative (2-year) clinical and radiological data including the range of motion, Constant Murley Score (CS), Subjective Shoulder Value (SSV), American Shoulder and Elbow Score (ASES), complications, and reoperations were collected. Pre- and postoperative results were compared with paired t-tests and Wilcoxon signed-rank tests.

Results: The mean age was 77 years (±7.2), 76% (16) were female, the mean body mass index was 29.9 kg/m² (±6.8), and 95% (20) were dominant side shoulders. The mean active elevation increased from 58 (±27.6) to 139.5 (±21) degrees (p < 0.0001). Likewise, the median external rotation in abduction (ER2) increased from 0 (IQR 0-10) to 75 (IQR 70-80) degrees (p < 0.0001), and the mean external rotation in the neutral position (ER1) increased from -4.1 (±9.6) to 11.2 (±12.2) degrees (p < 0.0001). Internal rotation decreased significantly from 5.0 (±1.2) to 3.8 (±1.8) points (p=0.034). The mean pre- and postoperative CS (22.6 ±8.3 to 72.6 ±8.4 (p < 0.0001)), ASES (32 ±9.9 to 88 ±5.5 (p < 0.0001)), and the SSV (25 ±13 to 83.8 ±9.3 (p < 0.0001)) improved significantly. No reoperation was required, but in one patient the tendon transfer did not heal.

Conclusion: Our findings showed that RSA combined with a modified L’Episcopo effectively restores active external rotation and abduction in patients with CLEER. Most clinical and radiological long-term outcomes were satisfactory, while the complication rate was relatively low (4.8%). Due to the surgically altered ratio of internal to external rotators, mean internal rotation decreased.

Recent results confirm the trend towards lateralizing arthroplasty designs in reverse shoulder arthroplasty (RSA). Aim of this study was to evaluate clinical and radiological mid-term outcomes of bipolar lateralization (metallic vs. bony augmentation) with isolated humeral lateralization (Lat.) in patients with cuff arthropathy (CTA) and osteoarthritis (OA).

Patients who underwent RSA between 05/2013 and 08/2019 with CTA or OA in one of two orthopaedic institutions were included. All received a curved 145° onlay stem system for humeral lateralization and were divided into 3 groups based on glenoid lateralization: no glenoid lat. (A), metallic augmentation (B) and bony-increased offset (BIO-RSA, C). Clinical evaluation included Constant Score (CS), Subjective Shoulder Value (SSV) and range of motion. Fractures, instabilities or loosening, scapular notching, stress shielding, osteolysis and other complications were examined radiologically.

A total of 80 patients (CTA: n=58; OA: n=32) were examined after an average of 73 (48-120) months. They achieved a CS of 71 (23-94) points, a SSV of 83% (10-100) with following range of motion: flexion 144° (50-180), abduction 143° (45-180), external rotation 25° (0-75), internal rotation in CS points 6.3 (0-10). Patients with OA showed significantly better clinical function regarding CS (78 vs. 69 p.; p=0.02), abduction (157 vs. 138 °; p=0.01), flexion (156 vs. 140 °; p=0.01), internal rotation (7.3 vs. 5.8 CS points; p=0.07) and had greater abduction strength compared to CTA patients (5.3 vs. 4.0 kg; p=0.04). There were no significant differences within groups A (n=26; mean 80.0 years), B (n=38; mean 79.1 years) and C (n=16; mean 78.5 years) regarding CS (A: 71, B: 73, C: 68 points), SSV (A: 82, B: 82, C: 85%) or range of motion. Metallic lat. showed a reduced rate of scapular notching (A: 42%, B: 18%, C: 31%; p=0.08). 57 patients (59%) showed radiologic stress shielding. 23 patients (29%) showed osteolysis in the humeral metaphysis. These radiologic changes had no influence on clinical function. No fractures, instabilities or loosening were detected in any of the three groups.

Humeral lat. using a curved 145° onlay stem achieves excellent clinical results in primary reverse shoulder arthroplasty (with or without additional glenoid lat.). Patients with OA show superior outcome at mid-term FU patients compared to CTA patients. Metallic lat. has a positive influence on reducing rates of scapular notching.

Einleitung
Zementierte, anatomische Schultertotalendoprothesen mit gekielter PE-Glenoidkomponente weisen im mittleren bis langfristigen Nachuntersuchungszeitraum „radiolucent lines“ (RLL) in über 50% der Fälle auf mit ebenfalls hohen Lockerungsraten. Ziel dieser Studie war es, die langfristigen Ergebnisse einer standardisierten knochensparenden und voll verteilten Zementiertechnik inkl. in Hinblick auf die RLL und klinischen Outcomes der Patienten zu beurteilen.

Material und Methodik
Dazu wurde eine retrospektive Kohortenstudie mit 38 konsekutiven Patienten (w=20; m= 18), welche in Folge einer primären Omarthrose mittels einer anatomisch schaftlosen Schultertotalendoprothese mit u.g. Zementiertechnik versorgt wurden, durchgeführt. Das durchschnittliche Alter bei der Operation betrug 66 (± 9,7) Jahre. Die Zementiertechnik wurde wie folgt durchgeführt:
1) Fräsung unter Erhalt des subchondralen Knochens
2) Spongiosaverdichtung des Kielbetts
3) Glenoidale K-Draht Bohrungen zur Zementverankerung
4) Ausgiebige Lavage
5) Ossäre Hämostase (Applikation lokaler Vasokonstriktoren)
6) Vollbeschichtete Zementapplikation der PE Rückfläche inklusive des Kiels
6) Fünfzehnminütige manuelle Kompression auf das Implantat

Zusätzlich erfolgte die standardisierte, dynamische Impingmenttestung der Probe-Glenoidkomponente um die implantierte Humeruskopfkomponente (Nyffeler-Test).

Radiologisch wurden die RLL um die glenoidale Komponente evaluiert. Klinisch wurde der Constant-Score (CS) und Subjektiver Schulterwert (SSV) erhoben.

Ergebnisse:
Insgesamt konnten 21 (w=11; m=10) Schultertotalendoprothesen mit einem durchschnittlichen Alter von 76 (±10,5) Jahren nachuntersucht werden. Der durchschnittliche Nachuntersuchungszeitraum betrug 9,2 (7-13) Jahre. RLL zeigten sich bei 8 Schultern (38%) um die glenoidale Komponente. Der durchschnittliche RLL-Score lag bei 0,95 (0-3). Der durchschnittliche Constant-Score lag bei 75,4 Punkten und der durchschnittliche SSV lag bei 80%. Insgesamt wurden vier Patienten aus der Patientenkohorte revidiert, resultierend in einer mittleren Überlebenszeit von 85,9% nach 97 Monaten.

Diskussion:
Die standardisierte Zementiertechnik gekielter, anatomischer Schultertotalendoprothesen unter Verwendung des Nyffeler Tests zeigt im Vgl. zur Literatur geringere Raten an RLL und exzellente klinische Langzeitergebnisse mit hoher Überlebensrate.

Introduction: We aim to study the outcomes of the anatomic total shoulder arthroplasty in B2 glenoids both before and after the 2012 publication by Walch et al. that recommended the use of reverse total shoulder arthroplasty (rTSA) for Walch Type B2 glenohumeral joint arthritis.

Methods: Using PRISMA guidelines, publications were identified that reported the outcomes for anatomic total shoulder arthroplasty used to manage the B2 glenoid. Only studies with minimal 2 years of follow-up were considered.

Results: In our two groups, pre-2012 and post-2012, we have 774 osteoarthritic B2 shoulders that were treated with an anatomic shoulder arthroplasty. The average follow-up was 64.2 versus 48.27 months. Over the last 10 years, prosthesis-related complication rates using eccentric reaming have significantly decreased from 13.77% to 3.28% (odds-ratio: 3.5; p-value: 0.0002; CI: 1.49-8.64). The use of posterior augmented glenoid implants has increased substantially and has maintained a consistently low complication rate of 2.8% (odds-ratio: 0.64; p-value: 0.684, CI: 0.12 - 3.25) with a mean follow-up of 32.7 months. When combining all surgical options for aTSA in the presence of a B2 glenoid, the results showed that patients after 2012 had significantly lower revision rates than patients before 2012 (odds-ratio: 3.12; p-value: 0.0012 CI: 1.56 - 6.1). In the first group, after the implantation of 166 prostheses, 16 complications occurred (9.6%). While in the 2 groups, 26 complications occurred after 608 operations (4.2%).

Conclusions: Anatomic total shoulder arthroplasty (aTSA) outcomes since 2012 have improved with lower prothesis-related complication rates when eccentric reaming and posterior augmented glenoid components were used.

Aim
The aim of this study was to compare the accuracy of glenoid component implantation in consecutive series of patients undergoing reverse shoulder arthroplasty with and without navigation, according to the wear patterns of the glenoid.

Background
Indications for reverse shoulder arthroplasty (RSA) have increased over the years and seems to yield satisfactory functional results even in patients with severe glenoid wear. New technologies such as navigation have gained in popularity with the aim to increase implantation precision, which is a crucial factor for long term implant survivorship. However, these technologies remain costly and their widespread use for everyday cases has yet to be determined.

Methods
Two consecutive series of patients operated on by the same shoulder surgeon for RSA, with and without navigation using the NextAR system (Medacta, Castel San Pietro, Switzerland), were prospectively included in the study. Revision procedures or RSA requiring glenoid bone graft were not included. Patients demographics (age, sex, side, BMI), preoperative diagnosis and glenoid wear patterns in both the coronal and axial planes were analyzed and defined as mild and severe. Postoperative implantation accuracy measurements were carried out on postoperative CT scans and consisted in RSA angle, version, maximal bone purchase of peripheral screws and central peg, and glenosphere position from the inferior glenoid neck according to Nyffeler.

Results
56 shoulders were included, 28 in each group. There were no significant differences in patient demographics, preoperative diagnosis, and wear pattern severity between both groups. In the navigated group, patients with severe bone wear presented a significantly higher accuracy in all analysed parameters, whereas patients with mild glenoid defects did not show significant differences in glenoid implantation version and glenosphere position from the inferior glenoid neck.

Conclusion
Navigation significantly improves glenoid implantation accuracy, particularly in patients with severe glenoid wear patterns. While its applicability in standard cases is debatable for experienced shoulder surgeons, it could prove valuable for patients with severe bone defects. Further studies are needed to assess if this will impact clinical and long-term implant survival outcomes.

Introduction: Positioning of glenoid component in reverse total shoulder arthroplasty (RTSA) may impact procedure’s safety and efficacy. Bony increased offset technique adds a level of complexity to the glenoid component positioning process. Optimisation of final passive soft tissue tensions have been reported to be determinant of postoperative joint stability as well as potential complications such as acromial/glenoid neck fractures and nerve traction injuries. In parallel, optimisation of impingement-free ranges of motion represents a key determinant of the procedure’s efficacy. Three-dimensional planning combined with intraoperative navigation emerges as a technical development for intraoperative surgeon assistance. Primary objective of this study was the evaluation of 3D preoperative planning fidelity during the intraoperative phase using navigation. Secondary objective was the analysis of functional outcomes of the procedure.

Methods: A sequential cohort of 100 primary RTSA was prospectively analysed. Preoperative glenoid component planning data and intraoperative navigation data before screw insertion were recorded. Advanced functional assessment of the shoulder using 3D motion capture was acquired preoperatively and at 1 year postoperatively.

Results: Difference in glenoid component positioning (mean ± SD) compared to preoperative 3D planning was 0.93 ± 3.13 mm for superior inclination, -0.69 ± 3.23 mm for retroversion, and -6.99 ± 3.17 mm for depth. Range of motion (mean ± SD) in forward elevation increased from 87.31 ± 35.30° to 116.19 ± 30.73° with a calculated difference of 28.88 ± 32.62°. Auto-evaluated pain on a scale of ten decreased from (mean ± SD) 4.25 ± 2.70 to 1.31 ± 2.16 with a calculated difference of -2.94 ± 2.85.

Conclusions and perspectives: Three-dimensional planning associated with navigation allows for accuracy of bony increased offset glenoid component positioning below 1° error in inclination and retroversion. Accuracy in depth positioning before tightening of screws remained over 5 mm. Further studies concerning depth are required with tools allowing for implant position recording after screw insertion. Functional outcome measurements showed satisfactory improvements in ranges of motion as well as diminution of pain. Further comparative studies between 3D planning associated with intraoperative navigation and 3D planning alone are underway.

Background:
Preoperative planning software enables the evaluation of various implant configurations and positions for reverse total shoulder arthroplasty (RTSA), with the objective to achieve stable fixation and maximal theoretical range of motion (ROM). However, it has been shown that simulated ROM without posture adjustment does not correlate well with postoperative ROM. The objective of this study was to compare simulated range of motion (ROM) for RTSA with and without adjustment for scapulothoracic orientation in a global reference system. We hypothesized that values for simulated ROM in a preoperative planning software with and without adjustment for scapulothoracic orientation would be significantly different.

Methods:
A statistical shape model of the entire humerus and scapula was fitted into 10 shoulder CT scans randomly selected from 162 patients who underwent RTSA. Six shoulder surgeons independently planned an RTSA in each model using a prototype development software with the ability to adjust for scapulothoracic orientation, starting position of the humerus, as well as kinematic planes in a global reference system simulating previously described posture types A, B, and C. ROM with and without posture adjustment was calculated for a total of 240 different case-scenarios and compared in all movement planes.

Results:
All movement planes showed significant differences when comparing protocols with and without adjustment for posture. The largest mean difference was seen in external rotation with 62° without adjustment compared to 25° with posture adjustment (p < 0.001), with the highest mean difference of 49° in type C. Extension was 57° without adjustment versus 24° with adjustment (p < 0.001) and the highest mean difference of 47° in type C. Abducted internal rotation was 69° without adjustment versus 31° with posture adjustment (p < 0.001), showing the highest mean difference of 51° in type C.

Conclusion:
The present study demonstrates that accounting for scapulothoracic orientation has a significant impact on simulated ROM for RTSA in all motion planes, particularly rendering vastly lower values for external rotation, extension, and high internal rotation. The substantial differences observed in this study warrant a critical reevaluation of all previously published studies that examined component choice and placement for optimized ROM in RTSA using conventional preoperative planning software.

Purpose:
This study aimed to evaluate whether shoulder functional internal rotation (fIR) after reverse shoulder arthroplasty (RSA) differs according to the size of implanted glenosphere.
Patients and Methods:
We retrospectively reviewed patients who had RSA between September 2015 and September 2020; 222 patients were eligible for inclusion and were operated upon by a single surgeon using a single implant. 132 (59.4%) were females, and the mean patients' age was 72±8 years. A 36 mm glenosphere was implanted in 109 patients (49%) and 39 mm glenosphere in 113 patients (51%). Clinical evaluation was performed using Simple shoulder value (SSV) and Constant score. The functional internal rotation (fRI) was evaluated and classified into type I if the hand blocked to the buttock, type II lumbar sliding, and type III smooth motion. Where type I was considered nonfunctional and type II and III as fRI.
Results:
After a mean follow-up of 24.7±4.1 months, the mean overall Constant score improved significantly from 42.81±15.25 points preoperatively to 73.44±11.80 points at the last follow-up (P < 0.001). The SSV improved significantly from 43.61±16.68 to 79.68±13.17 (P < 0.001). The fIR was classified preoperatively as type I in 57 (25.6%) patients, type II in 106 (47.7%), and type III in 59 (26.5%), which changed at the last follow-up to type I in 64 (28.8%) patients, type II in 80 (36%), and type III in 78 (35.1%). There was a non-significant change (p=0.53) and (p=0.17) in the 36 mm and 39 mm glenosphere, respectively.
Conclusion:
We found that there was no significant impact exists between the different glenosphere sizes and postoperative fRI. Nearly 70% of the patients regain postoperatively a fIR.

Background: Movement limitations after RTSA have been observed in some patients postoperatively, with implant design and positioning recognized as influential factors. Recent analyses have identified three scapular postures in the population that might affect range of movement (ROM). However, no clinical study has explored their impact on clinical outcome so far. It was the aim of this study to correlate patient´s posture with the clinical outcome (including ROM) and further correlate photo documented posture to measurement of scapula position on computed tomography (CT).

Methods: A prospectively enrolled RTSA database was retrospectively reviewed, and 360 consecutive patients met the inclusion criteria at minimum follow-up of 2 years. Patient´s posture was analyzed using photo documentation. The posture was defined following Moroder´s classification as Type A (upright posture, retracted scapulae), type B (intermediate), type C (kyphotic posture with protracted scapulae). CT data were used to measure scapula position (internal rotation). Correlation analyses between them were conducted. Postoperative ROM and clinical outcomes (absolute and relative Constant Score (CSa, CSr)) were compared between the different posture types.

Results: According to the clinical posture type, the patients were divided into posture type A (n=69), B (n=253) and C (n=48). Average CSa differed significantly among groups (69±16 vs 69±14 vs 64±16, p < 0.05) favoring patients with posture types A and B over type C. In terms of ROM, flexion, abduction and internal rotation significantly differed among groups. Types A and B exhibited better flexion and abduction (flexion 124±26º and 123±23º vs. 113±25º, abduction 140±34º and 137±30º vs 128±34º). Patients with posture type A demonstrated superior internal rotation (5.86±2.94 vs 5.00±2.68 vs 4.38±2.79, p < 0.05). External rotation was similar between the groups (33 ± 17° vs 30 ± 16° vs 28 ± 18°, p=0.3) but significantly better for type A compared to type C. Correlation analysis between clinical assessment and CT measurement showed very poor reliability (Correlation = 0.35).

Conclusion: Patients with clinical posture types A and B exhibit improved ROM values compared to type C postures. Clinical outcome scores was also notably superior in types A and B. Scapulothoracic orientation should be a crucial consideration in RTSA planning, influencing ROM and clinical outcomes.

Introduction – Three-dimensional (3D) scapula morphology measures on CT are more accurate and precise than standard two-dimensional (2D) measurements. Equivalent 3D scapula morphology measurements on diagnostic MRI are impeded, however, due to the reduced image resolution and field of view which excludes the medical and inferior scapular borders. We hypothesised, that deep-learning based algorithms exploiting high resolution knowledge from CT, could enable automatic 3D scapular morphology analysis on diagnostic MRI, with equivalent accuracy to CT.
Methods - A deep-learning based segmentation network for prediction of the scapula from MRI was trained on CT and MRI data from the same shoulder of 20 rotator cuff tear patients. Manual segmentations from CT were aligned to the corresponding MRI and used to train a deep-learning network to automatically segment the scapular on multiplanar MRI (coronal, sagittal and transverse orientations). An algorithm to combine segmentation information from the three planes to generate high-resolution 3D models from the anisotropic MRI data was also developed. For the automatic calculation of common morphological measures, a second deep-learning network was trained to predict the location of anatomical landmarks and scapular axes on the 3D scapula models. Differences between morphology metrics automatically calculated on MRI and on corresponding CT were evaluated on 10 patients using the paired t-test and the intraclass correlation coefficient (ICC).
Results – Morphological measurements were automatically calculated on MRI, with no statistically significant differences from values calculated on CT (P < 0.05). The ICC between values calculated on CT and MRI were: 0.73 for the glenoid version, 0.81 for the glenoid width, 0.89 for the glenoid height, 0.93 for the glenoid inclination and 0.91 for the critical shoulder angle.
Conclusion – This study presents deep learning-based algorithms for automatic scapular morphology analysis from diagnostic MRI. By training deep-learning networks on higher resolution CT based complete scapular models and by combining the information from different MRI planes, challenges posed by the reduced resolution and restricted FOV of diagnostic MR was overcome. Our approach facilitates the application of accurate 3D scapula morphology analysis on patients with diagnostic MRI, eliminating reliance on CT imaging.