Apprehension of the shoulder is a complex pathological process, not limited to peripheral mechanical problems. In fact, this process can be linked to peripheral or central neurological alterations. The latter aspect having been investigated 10 years ago in previous works, our team was able to demonstrate morphological alterations in white matter and changes in the activity of neuronal networks, such as primary sensory-motor areas, dorsolateral prefrontal cortex, the dorsal anterior cingulate cortex/dorsomedial prefrontal cortex and anterior insula, 10 years after shoulder stabilization surgery. The aim of this study was to evaluate the evolution of these modifications 10 years after shoulder stabilization surgery.

Ten patients (average age 38.6±9.7 years) who had undergone shoulder stabilization and nine controls (average age 40.6±2.9 years) from the original study (Y0) took part in this ten-year follow-up prospective comparative study (Y10). We replicated the same experimental procedure, which included functional magnetic resonance imaging (fMRI) with videos designed to induce shoulder apprehension, structural MRI, and comprehensive clinical assessments.

In terms of task-related functional imaging, patients exhibited a complete reduction in apprehension-related brain activations at Y10 compared to Y0. Notably, there were no significant differences in the equivalent analysis of the control group, which eliminates the potential bias of re-testing or aging. In terms of functional connectivity, the differences observed in several brain networks at Y0 between patients and controls nearly completely normalized at Y10, except for a minor remaining difference in the insula/auditory network. There were no significant structural differences in brain grey matter or white matter observed between Y0 and Y10 in both patients and controls. Regarding clinical parameters, patients showed improvement at Y10 compared to Y0 across all scores.

In patients experiencing shoulder apprehension, brain activations associated with apprehension showed a near-complete normalization ten years after successful shoulder stabilization.

Résumé
Contexte : La stabilisation osseuse de l'épaule par la technique arthroscopique de Latarjet est connue depuis 2007.
Nous souhaitons évaluer de manière innovante et objective l'état postopératoire du patient en analysant l'épaule selon la méthode S-START, permettant de valider la reprise du sport après chirurgie stabilisatrice de l'épaule.
L'objectif principal de cette étude est d'évaluer la satisfaction des patients après la réalisation de ce test.
Méthodes : Nous avons réalisé une étude monocentrique rétrospective de 2018 à 2023 incluant tous les Latarjet arthroscopiques, réalisés par 1 chirurgien senior, selon 1 technique. Nous avons inclus 81 patients ayant bénéficié d'une arthroscopie et adressés à notre équipe de médecins du sport et de kinésithérapeutes pour une étude approfondie de leur épaule selon la méthode S-Start (Shoulder-SanTy Athletic Return To Sport). Le S-START combine une analyse de la composante psychologique, le rapport dominant/non-dominant de la force maximale IR, le rapport dominant/non-dominant de la force maximale RE, le rapport dominant/non-dominant USSPT (%) (Unilateral Seated Shot Put Test in Rehabilitation), le rapport RE/RI du côté opéré, le rapport dominant/non-dominant UQYBT (The Upper Quarter Y-Balance Test), l'analyse CKCUEST (Closed Kinetic Chain Upper Extremity Stability Test) et l'indice d'endurance aboutissant à un score total sur 100.
Résultats : Nous avons eu 100% de Latarjet arthroscopique, un âge moyen de 28,9 ans, 75% d'hommes, 45,8% de côté droit, 73% opérés du côté dominant.
En moyenne, nos patients se sentaient prêts psychologiquement à 71% à reprendre les sports à risque et avaient un score total de 66/100.
En ce qui concerne notre objectif principal, 92% de nos patients se sont sentis satisfaits du test, dont 94% qui le referaient, 90% qui en ont retiré un bénéfice et 88% qui l'ont trouvé adapté à leur situation.
Conclusions : Nous avons un score de satisfaction de 92% pour ce test qui fournit une indication fiable et objective permettant d'autoriser une reprise des sports à risque en toute sérénité. D'autres études sont nécessaires et nous souhaiterions réaliser une étude prospective pour évaluer les bénéfices des indications du S-start à court terme.

Background
Concern exists that the Latarjet procedure may negatively affect range of motion (ROM). We hypothesize that the Latarjet procedure results in full recuperation of ROM postoperatively and significantly improved patient reported outcome measures.
Methods
Patient data were prospectively collected in a database to analyze outcomes after open Latarjet procedure. Inclusion criteria involved a minimum follow-up of six months and unilateral shoulder instability. Study outcome was assessed by postoperative ROM at six months postoperatively and compared to the preoperative ROM of the ipsilateral shoulder as well as the ROM of the unaffected contralateral shoulder. All ROM measurements were performed utilizing a motion capture system to ensure consistent and reliable measurements. As a secondary outcome, the effect of sling on postoperative ROM was analyzed. Patient reported outcomes were also evaluated.
Results
The study included a total of 84 patients. ROM was measured in external rotation with the shoulder adducted (ER1), external rotation with the shoulder abducted 90 degrees (ER2), internal rotation with the arm abducted 90 degrees (IR2), and active forward elevation (AE). The average difference in ROM between the operated arm vs. the contralateral healthy arm at six months postoperatively was 3.4 degrees in ER1 (p=0.19), 4.2 degrees in ER2 (p=0.086), 2.2 degrees in IR2 (p=0.36), and 2.4 degrees in AE (p=0.045). Sub-analysis of patients with and without sling use revealed no significant difference in ROM between the operated shoulder and contralateral shoulder at six months in either group, with the exception of ER2 in the sling group. In this latter group, ROM was 71 degrees in the operated arm and 79 degrees in the contralateral arm (p=0.0094).

Conclusions
Latarjet procedure performed for anterior instability utilizing a capsular repair result in complete ROM recovery in ER1, ER2 and IR2 at six months postoperatively, with only a slight discrepancy in active elevation.

Introduction: The assessment of posterior humeral head subluxation (HSI) is important for preoperative planning of total shoulder arthroplasty. As 3D planning tools gain popularity, two 3D measurement techniques for posterior humeral head subluxation have been introduced: an offset-based type similar to the original 2D measurement, and a volumetric type using the volumes of the humeral head as divided by the plane of the scapula. The purpose of this study was to compare both 3D measurement techniques in a mathematical model and a clinical cohort.

Methods:
For the mathematical model, both offset-based and volumetric HSI were computed using a humeral head diameter of 50 mm. Offset-based HSI was calculated with 0.5 mm increments of posterior offset to the scapula in relation to the humeral head diameter. Volumes of the corresponding spherical caps were calculated for the same offset increments according to the mathematical formula. Volumetric HSI was calculated by putting the spherical cap volume in relation to the remaining volume of the corresponding sphere. Differences between both methods were plotted on a comparative graph.
In a clinical cohort of 55 patients with primary osteoarthritis, both offset-based and volumetric HSI were measured in 3D. Bland-Altman plots and paired t-tests were used for comparison.

Results:
Given the mean difference of 0.05% (p = 0.830), the clinical cohort validated the mathematical model. Volumetric HSI was greater for all values except for 0%, 50%, and 100% of posterior subluxation. The mean difference between both HSI techniques was 6% (p < 0.001), with a maximum difference of 9% between 73% and 84% offset-based HSI. A non-linear relationship was shown between the two.

Conclusion:
Offset-based HSI and volumetric HSI are inherently different measurements with a non-linear relationship. Therefore, the values of both measurements cannot be interchangeably used. The plotted differences of this study can be used as a correction table, allowing values to be compared within the literature. The geometrical differences between the two measurements explain the inherent differences: offset-based HSI corresponds to a cube in 3D, whereas volumetric HSI corresponds to a sphere. Because the sphere "cuts the corners" of the corresponding cube, the sphere cap at a given posterior offset will be smaller than the cube section at the same point, resulting in a larger posterior HSI unless the humeral head is centered or fully subluxated.

Background: The Latarjet procedure enables effective shoulder stabilization and rapid functional recovery of shoulder in most cases. However, the influence of the coracoid graft position at the glenoid on patient reported outcome measures (PROMs) remains uncertain.

Aim: This study aimed therefore to analyze the effect of graft position on 6-month PROMs after the Latarjet procedure.

Hypothesis: We hypothesized that, while lateralization and/or distalization of the graft at the glenoid would improve apprehension, it would also be a cause of pain and reduced function.

Methods: This was a prospective monocentric sturdy. All patients operated on with a Latarjet procedure and had available preop and 6-month postop CT scans were eligible. Patients with incomplete radiological data sets, poor image quality or lost to follow-up before 6 months were excluded. An experienced surgeon performed all procedures using a free-hand technique to place the graft at the glenoid. All patients underwent a standardized assessment before and at 6 months after surgery. Collected data included The ROWE score, Single Assessment Numeric Evaluation (SANE) for instability and Visual Analogue Scale (VAS) for pain. In addition, an independent observer performed a standardized 3D CT scan analysis with the Osirix software for preoperative bipolar glenoid bone loss (Sugaya H et al, JBJS Am 2003; Di Giacomo G et al, Arthroscopy 2014) and postoperative coracoid graft positioning separately in the axial and frontal planes (Kraus TM et al, KSSTA 2013)

Results: Of 108 Latarjet procedures between 04/2018 and 03/2021, 82 could finally be include (76%). The mean age at surgery was 28.0±9.0. Preoperatively, the mean glenoid bone loss was 14.4% and 79 patients (96%) had an Hill-Sachs lesion. Preoperatively, 25% cases were "off-track" vs. 6% at last follow-up. There was a postoperative improvement in the VAS for pain (27±21 vs. 13.8±17.2, p < 0.001), SANE score (41.8±21 vs 85.7±12.7, p < 0.001) and ROWE score (38.0±19.4 vs. 83.3±15.6, p < 0.001). Graft lateralization was associated with a lower postoperative ROWE score improvement and worse VAS for pain.

Conclusion : This study highlighted the importance of coracoid graft position after a Latarjet procedure. At 6 months, graft lateralization was associated with reduced function and increased pain.

Background: The popularity of team handball is increasing with over 10 million children playing this overhead, throwing and collision sport with highest demands on the shoulder joint. Due to the risk for recurrent instability, the Latarjet-Patte (LP) procedure has been recommended to treat young competitive players. This is the first LP outcome study in professional handball.
Methods: We included 20 shoulders retrospectively (18 players/17 males/mean age 22.9 years, range 17-35 years; minimum/mean follow-up: 2/6.6 years) operated on by three expert surgeons (2011-2020) with Walch’s LP-technique. Preoperative hyperlaxity (25%/n=5), affected throwing arm (55%/n=11), position (backcourt, winger, goalkeeper: 22% each; full back, pivot: 17% each), >2 dislocations prior (20%/n=4), >10 dislocations (5%/n=1), previous failed Bankart/HAGL repair (10%/n=2) and large Hill-Sachs lesions (HSL: 20%/n=4) were documented. Clinical and radiographic outcomes, visual analogue scale (VAS), subjective shoulder value (SSV), Walch-Duplay (WDS), Rowe score (RS) and return to sports (RTS) parameter were recorded.
Results: RTS was 85% (n=17/20), RTS to same-level 80% (n=16/20), RTS with no throwing pain 73% (n=8/11), time to training with ball: 3.2/12 and to competition 4.9/12. The mean RS, WDS and SSV were 90, 88, 89 % respectively. Shoulder symptoms lead to giving up handball in 2 cases (10%). One player (5%) stopped for other reasons. One recurrent dislocation (5%) was recorded (non-throwing arm, winger, no recurrence after rehabilitation). Persistent apprehension occurred in one goalkeeper (5%). Four shoulders showed residual pain (20%) relieved in one by screw removal. Resistant pain (throwing shoulder) was seen in 2 backcourt players (10%/one large HSL) and one goal keeper (5%/large HSL; >10 dislocations prior), all three >30years of age. Bone block positioning was correct (no lateral overhang) in all shoulders. One shoulder (5%) showed mild arthritic changes at final follow up (>10 dislocations, large HSL).
Conclusion: The open Latarjet-Patte is consistent in providing shoulder stability combined with return to throwing performance in professional handball players with a short time to RTS and high same-level RTS rate without increasing the risk of arthritic changes. Throwing shoulders of backcourt players, with large HSL or shoulders at age >30 years may have an increased risk for persistent symptoms.

Background : The success of anterior shoulder stabilization with the Latarjet procedure depends on the correct positioning of the coracoid graft at the glenoid. However, its ideal 3D position remains a source of debate.

Aim : This study aimed to analyze the effect of graft position on 6-month range of motion (ROM) after the Latarjet procedure.

Hypothesis : We hypothesized that ROM would gradually decline with increasing lateralization and/or distalization of the graft at the glenoid.

Methods : This was a prospective monocentric sturdy. All patients operated on with a Latarjet procedure and had available preop and 6-month postop CT scans were eligible. Patients with incomplete data sets, poor image quality or lost to follow-up before 6 months were excluded. An experienced surgeon performed all procedures using a free-hand technique to place the graft at the glenoid. All patients underwent a standardized assessment before and at 6 months after surgery. An independent observer collected active ROM with a motion-capture system (Vicon, Oxford Metrics, Oxford, UK). Another independent observer performed a standardized 3D CT scan analysis for preoperative bipolar glenoid bone loss (Sugaya H et al, JBJS Am 2003; Di Giacomo G et al, Arthroscopy 2014) and postoperative coracoid graft position separately in the axial and frontal planes (Kraus TM et al, KSSTA 2013)

Results : Of 108 Latarjet procedures between 04/2018 and 03/2021, 82 could finally be include (76%). The mean age at surgery was 28.0±9.0. Preoperatively, the mean glenoid bone loss was 14.4% and 79 patients (96%) had an Hill-Sachs lesion. Preoperatively, 25% cases were "off-track" vs 6% at last follow-up. Anterior elevation (AE) improved from 170° to 175° (p < 0.001) and external rotation (ER1) improved from 48° to 54° (p < 0.003). Graft overhang was associated with decreased AE (beta, -8.2°, p = 0.034). Graft distalization was correlated with a greater postoperative improvement in ER1 (beta, 0.3°, p = 0.028) .

Conclusion: This study highlighted the importance of coracoid graft position after a Latarjet procedure. At 6 months, graft overhang was associated with decreased AE (beta, -8.2°, p=0.034) and graft distalization was correlated with a greater postoperative improvement in ER1.

Introduction:
The most commonly reported complication after AC joint stabilization is loss of reduction. One possible cause is tunnel positioning. The aim of this study was to investigate the association between coracoclavicular (CC), coracoidal tunnel position and LOR.

Methods:
We included male patients (aged 18-55 years) with an acute, high-grade ACJ dislocation (Rockwood type V), who were treated arthroscopically-assisted with a Low-Profile TightRope combined with a percutaneous acromioclavicular cerclage.
Panorama views were used to measure the CC tunnel angle (CCAP) and offset angle (CCTA) as well as the mediolateral coracoidal tunnel position (from medial, in absolute and relative terms regarding coracoid diameter) at the 6 weeks-follow-up.
We analyzed these factors in relation to LOR (difference in side-comparative CC distance at the 6-weeks-FU and the final FU of at least 2 years). A p-value of less than 0.05 was considered statistically significant. Statistical analysis included Pearson’s correlation coefficients and the Mann-Whitney-U-test.

Results:
Twenty-five patients with a mean age of 37.8 years (range, 23 years to 54 years) at a mean FU of 25.8 months (range, 24 months – 36 months) were included.
The mean LOR was 3.5mm (95% confidence interval, CI: 2.5mm – 4.5mm). No significant correlation were found with CTAP (mean 2.4°, 95% CI: 1.8° – 3.1°) (r = -0.137; p = 0.513), but there was a trend towards correlation with the CCTA (mean: 11.8°, 95% CI: 7.0° – 16.6°) (r = -0.347; p = 0.090).
The LOR was not associated with coracoid diameter (22.5mm, 95% CI: 21.4mm – 23.7mm) (r = -0.256, p = 0.216), or the absolute mediolateral coracoidal tunnel position (r = 0.226; p = 0.277; mean: 12.6mm, 95% CI: 11.6mm – 13.6mm). However, there was a positive correlation with the relative mediolateral coracoidal tunnel position (r = 0.41; p = 0.03) (mean: 0.56, 95% CI: 0.52 – 0.60). Specifically, LOR was higher in cases with a relative tunnel position of > =0.61 (5.1mm, 95% CI: 2.9mm – 7.2mm vs. 2.6mm, 95% CI: 1.7mm – 3.5mm; p = 0.014).

Conclusion:
After bidirectional, arthroscopically-assisted ACJ stabilization, a laterally positioned coracoid tunnel was associated with more LOR, while overreduction according to the CCTA trended towards an association with less LOR.
Considering these aspects appears to improve the postoperative healing result in the longer term.

Background: Posterior labral tears, glenoid retroversion and posterior glenoid bone loss are clinically and biomechanically proven factors that decrease resistance to humeral head translation in response to a posteriorly directed force. However, failure rates of conservative and surgical treatment are high. A high and flat acromion, implying less posterior humeral head coverage, has been shown to be associated with posterior instability. It was the purpose of this study to evaluate the stabilizing effect of the acromion to posterior humeral head translation.
Methods: Eight fresh-frozen cadaver shoulders were biomechanically tested in a shoulder simulator in the load-and-shift and the Jerk test position. Prior to testing, CT scans were performed on all shoulders to measure native glenoid width, glenoid retroversion, posterior acromial coverage (PAC), sagittal acromial tilt (SAT) and posterior acromial height (PAH). Each of the specimens underwent six testing conditions using 3D printed cutting and reduction guides: (1) Intact joint, native acromion (2) Intact joint, severe acromial pathology (SAT 69°, PAC 47°, PAH 26mm) (3) Scenario 2 + posterior acromial bone block (PABB) (4) Intact joint, medium acromial pathology (SAT 59°, PAC 57°, PAH 20mm) (5) Scenario 4 + PABB and (6) Intact joint, corrected acromial alignment (SAT 48°, PAC 70°, PAH 11mm). The degree of acromial malalignment and acromial reorientation was chosen based on a previous study that defined acromial anatomy in patients with posterior instability. The humeral head was translated posteriorly until either (1) a peak force of 150N or (2) a maximum posterior translation of 50% of the glenoid width were reached. Forces (N) and translations (mm) were recorded. Testing was repeated three times per condition and mean values were used for analysis.
Results: Mean native glenoid width was 25.4mm (21-31mm), glenoid retroversion was 3.1° (1.3-5.8°), SAT was 58.6° (41.1-72.6°), PAC was 63.6° (54.4-77.6°), PAH was 18.9mm (8.5-24.5mm). Realigning the acromion or adding a PABB significantly increased stability compared with the medium and severe pathology in all tests (p < 0.05). There were no significant differences between the native shoulder and the medium pathology.
Conclusions: The acromion acts as a restraint to posterior humeral head translation. Correction of acromial malalignment or addition of a PABB can effectively restore glenohumeral stability.

Introduction:
The etiology of posterior shoulder instability (p.s.i.) is unknown. Recent 2- and 3-D studies documented consistent abnormalities in position and orientation of the acromion and the glenoid. Biomechanical studies suggest that correction of the specific deformities may correct p.s.i.. It was the purpose of the present, preliminary study to test the hypothesis that isolated correction of scapular anatomy could correct p.s.i..
Methods:
Nine consecutive cases with p.s.i. refractory to conservative and in in 6 cases operative treatment were entered. A CT of the affected shoulder was segmented and compared with a statistical mean shape model of a normal shoulder. Corrective osteotomies of the acromion and of the glenoid were 3-D planned and personalized cutting and reduction jigs manufactured to allow restoration of normal anatomy. After informed consent all patients were operated and followed up for a minimum of 24 months.
Results:
At 24 months there was one clinical failure with pain and progressive static posterior subluxation. Repeat CT showed that anatomic correction had not been achieved in this case. All patients were dynamically stable. The median SSV had increased from 30 to 80%, the median Constant Score from 54 to 81%, the median pain score from 6 to 13 points. Subjective shoulder state was excellent in 6, good in 1, fair and 1 and poor in 1 case (Preop assessment 0/0/3/6).Static subluxation was better in 4, same in 4 and worse in 1 case.
Discussion:
Acromial position and orientation have never been considered as a cause of p.s.i., but their consistent abnormal position and form in p.s.i. have been established in former investigations. Biomechnical studies support that the pathological anatomy of glenoid and particularly the acromion are (co-) responsible for p.s.i. This preliminary report documents that restoration of scapular anatomy to normal corrects dynamic p.s.i in 8 of 8 patients up to two years and isolates static p.s.i in one. In a case where the correction was unsuccessful, static subluxation increased. At this time, the precision of the realization of the procedure needs further improvement. The results, however, already support the hypothesis that p.s.i. may be successfully treated with restoration of normal scapular anatomy using the SCOPE (scapular corrective osteotomies for posterior escape) procedure and that this approach might open a new pathway for prevention or correction of static and dynamic p.s.i.

Partial rotator cuff tears (PTRCTs) are a common cause of shoulder pain. While PTRCTs are preferably managed conservatively, conversion to a surgical approach may be indicated. It is unclear, which technique provides best outcome for different tear locations. Our objective was to investigate the epidemiology of partial rotator cuff tears and applied arthroscopic surgical repair techniques and to compare outcomes of different PTRCTs based on tear location.

From June 2020, a cohort of 973 arthroscopic rotator cuff repair (ARCR) patients was prospectively enrolled at 19 centers and was followed up for 24 months. Patients with a PTRCT underwent surgery using the technique applied on each study site. Tear location and surgical technique were documented intraoperatively. Functional outcome (Constant Murley Score [CMS], pain level, range of motion [ROM], strength) was assessed at baseline and 12-months follow-up. Structural outcome was assessed using ultrasound after 12 months. The variability of tear patterns and applied treatment between sites were described. For PTRCT involving the supraspinatus (SSP) tendon functional and radiographic outcomes were compared between tear locations (articular-side vs bursa-side vs interstitial).

The ARCR cohort included 147 (15.7%) partial tears, thereof 128 (87%) involved the SSP tendon with 69 (54%) articular-sided, 35 (27%) bursa-sided, and 24 (19%) interstitial tears. SSP PTRCTs were repaired in 122 patients, using single row (45%), double row (19%) or transosseous-equivalent (36%) techniques. ROM at 12-month follow-up significantly differed for flexion (164°, 150°, 156°; p=0.007), abduction (160°, 145°, 154°, p=0.044) and internal rotation (53°, 33°,27°; p < 0.001) in favour of articular-sided tears when compared to bursa-sided and interstitial tears, respectively. CMS, pain level and strength did not significantly differ between groups. Ultrasound revealed no repair failure in the articular-side group and 2 repair failures each in the bursa-side (7%) and interstitial (11%) groups (p=0.054).

PTRCT account for a non-negligible number of ARCRs. No common surgical approach exists, resulting in a variety of applied techniques. While all within-tendon tear locations showed similar improvement in functional outcomes, pain and strength at 12-month follow-up, ROM for flexion, abduction and internal rotation recovered better in patients with articular-sided tears when compared to bursa-sided and interstitial tears.

Prediction models for outcomes after orthopedic surgery provide patients with evidence-based postoperative outcome expectations. The objective of this study was to update and validate a clinical prediction model for the improvement of shoulder function, using the 6-month Oxford Shoulder Score (OSS), for patients undergoing an arthroscopic rotator cuff repair (ARCR) in Switzerland.

Methods

Between June 2020 and November 2021, included 973 primary ARCR patients were prospectively enrolled in the ARCR_Pred study across 18 Swiss and one German orthopedic center and were followed up for 24 months postoperatively. Available patient-reported Oxford Shoulder Score (OSS) data were used at 6-month (N = 910). An already developed 7-factor model (ASA Classification, symptom duration, baseline level of depression and anxiety, baseline OSS, operation duration, tear severity, and biceps status and treatment) was externally validated on the ARCR_Pred data. Models were compared in terms of R-squared and root-mean-squared-error (RMSE). The same set of 32 prognostic factors identified through a systematic review and completed by an expert opinion were used for model update. Final updated model was identified using a backward elimination procedure minimizing the Akaike’s Information Criterion (AIC).

Results

After recalibration on the ARCR_Pred data, the apparent model performance was R-squared = 20.7% and RMSE = 6.77. The final updated model had a better apparent R-squared = 24% and a RMSE = 6.62 and included the following parameters: age, smoking status, pre-operative medication, pre-operative steroid infiltrations, length of symptoms duration, baseline level of anxiety, baseline OSS, performance of an acromioclavicular joint resection and performance of a capsulotomy.

Conclusion

Performance of a similar model development procedure on an independent dataset highlighted the importance of the following selected variables in the prediction of the OSS at 6-month: symptoms duration, baseline level of anxiety, baseline OSS. We also highlighted the improvement in our model performance using our nationwide multicenter cohort study, the ARCR_Pred data.

Introduction
A prospective multicenter study (ARCR_Pred) was implemented to document the effectiveness of arthroscopic rotator cuff repair (ARCR) in a representative Swiss patient cohort. The purpose of this analysis was to investigate the diagnostic value of the lift-off test for subscapularis (SSC) tendon rupture with consideration of intraoperative findings as reference standard.

Methods
Between June 2020 and November 2021, a cohort of 973 primary ARCR patients was prospectively enrolled at 18 Swiss orthopedic centers and one German center. Prior to shoulder arthroscopy, patients were evaluated with the lift-off test when possible to assess for SSC tendon tears. The intraoperative finding of SSC lesions was used as the reference standard to investigate the test characteristics of the lift-off test. Patient characteristics and concomitant pathologies influencing the ability to implement the test, as well as test sensitivity were explored.

Results
Among the 973 patients enrolled, 679 (69.8%) were able to perform a lift-off test at baseline. Of these,154 (22.7%) tested positive. Intraoperatively, SSC tendon tears were diagnosed in 309 (45.5%) patients, with 68.6% classified as complete tears and 31.4 % as partial tears. The lift-off test demonstrated a sensitivity of 64% (95% CI 56% to 71%) and specificity of 77% (74% to 81%) for detecting any type of SSC tendon injury. Notably, a positive correlation was observed between lift-off test sensitivity and the severity of the subscapularis tear. For full-thickness tears (Lafosse II-V), sensitivity and specificity were calculated at 45.6% (38.8% to 52.5%) and 74.5% (64.3% to 82.7%), respectively. The positive and negative predictive values were 45.6% (38.8% to 52.5%) and 37.4% (30.6% to 44.8%), respectively. Despite of SSC lesions, a tear of the supraspinatus tendon and a rupture of the biceps pulley or the long head of the biceps (LHB) were associated with a positive result of the lift-off test (p < 0.05). Several factors like age, body mass index (BMI), trauma or pain level decreased the clinical feasibility of the lift-off test due to limitation of active internal rotation.

Conclusion
Our analysis confirms prior research, indicating the lift-off test's limited sensitivity in detecting SSC tendon tears. Sensitivity increased slightly when considering full-thickness SSC tears only. The implementation of the lift-off test is affected by age, BMI, trauma and pathologies to the supraspinatus tendon and the LHB.

Studien zeigen, dass die Erfahrung der Chirurgen und hohe chirurgische Fallzahlen bei orthopädischen Eingriffen mit den klinischen Ergebnissen korrelieren. Diese Studie untersucht, ob chirurgische Erfahrung oder hohe Fallzahlen mit besseren klinischen Ergebnissen nach arthroskopischer Rotatorenmanschettenrekonstruktionen (ARCR) assoziiert sind.
Primäre ARCR bei 973 Patienten aus 19 orthopädischen Kliniken wurden prospektiv über 24 Monate beobachtet. Nebst klinischem Assessment, sonographischer Integrität und Patientenevaluation nach 12 Monaten wurden der Subjective Shoulder Value, Constant Score, Oxford Shoulder Score und die Lebensqualität (European Quality of Life 5 Dimensions 5 Level questionnaire, EQL5D5L) erfasst. Multiple Regressionsmodelle (adjust. n. Alter, Rupturausmaß, Nebenerkrankungen) wurden erstellt, um die Vorhersagemöglichkeit der klinischen Entwicklung anhand der jährlichen ARCR-Fallzahlen zu testen. Zudem wurde ein multivariates, logistisches Regressionsmodel konzipiert, um zu prüfen ob chirurgische Fallzahlen Komplikationen (Adverse Events (AE)) vorhersagen können. Mittels Clusteranalyse mit Gruppierung der Patienten anhand der chirurgischen Erfahrung (orthopädische bzw. schulterchirurgische Erfahrung; hierarchische Position) wurde der Zusammenhang mit den klinischen Ergebnissen untersucht.
ARCR-Fallzahlen waren ein starker Prädiktor für verbesserte klinische Ergebnisse nach ARCR: In der multivariaten, linearen Regressionsanalyse waren die Fallzahlen unabhängig mit der Lebensqualität (EQL5D5L) (β = 0.02, 95% CI: 0.0098, 0.0347,p < 0.001), Constant Score (β = 2.68,95% CI: 1.57,3.79,p < 0.001), Schulter Funktion (β = 1.10, 95% CI: 0.48, 1.72, p < 0.001) und Schmerz assoziiert (β = -0.35, 95% CI: -0.54,(-0.17), p < 0.001). Im Gruppenvergleich zeigte sich ein Trend für bessere klinische Ergebnisse ab 50 Operationen/Jahr. Fallzahlen waren kein Prädiktor für weniger AE (OR 1.36, 95% CI: -0.25, 0.92;p= 0.29). Die Cluster Analyse ließ 3 Patientengruppen (operiert von: Kaderarzt mit langjähriger und schulter-spezifischer Erfahrung oder intermediärer Erfahrung oder Oberarzt mit eingeschränkter Spezialisierung) erkennen, ohne sign. Unterschiede bzgl. aller klinischen Parameter oder AEs (p > 0.05).
Höhere ARCR-Fallzahlen können ein besseres klinisches Ergebnis prognostizieren. Gleichzeitig scheinen die Jahre an orthopädischer. bzw. schulterchirurgischer Praxis keine direkte Assoziation zu den untersuchten klinischen Parametern oder AEs aufzuweisen.

Purpose: To compare the clinical and functional outcomes of arthroscopic rotator cuff repair over a period of 2 years using three postoperative rehabilitation modalities: aquatic therapy, land-based therapy, and self-rehabilitation therapy. The null hypothesis was that aquatic therapy would provide no difference in Constant score compared to land-based therapy and self-rehabilitation therapy.

Methods: A prospective study was performed on subjects scheduled for arthroscopic rotator cuff repair between 2012 and 2017 that complied with the following criteria: (i) small to medium sized symptomatic supraspinatus and/ or infraspinatus tendon tears, (ii) low to moderate tendon retraction according to Patte, and (iii) fatty infiltration stage ≤2 according to Goutallier. Patients were allocated to perform either aquatic therapy, land-based therapy, or self-rehabilitation therapy for 2-4 months. Independent observers blinded to the study design collected Constant score, SSV, and patient satisfaction at 2 months, 3 months, 6 months, 1 year and 2 years.

Study design: Level III, cohort study

Results: At 2 months follow-up, patients performing aquatic therapy had significantly higher Constant scores (p < 0.001) and SSV (p < 0.001) compared to those performing land-based therapy or self-rehabilitation therapy. At 3 months follow-up, patients performing aquatic therapy kept significantly higher Constant scores (p < 0.001), and SSV (p < 0.001), both of which exceeded the respective minimal clinically important differences (MCIDs) of 10.4 and 12.
Patients performing aquatic therapy continued to have higher Constant scores and SSV at 6 months, 1 year, and 2 years, although the difference in Constant scores were less marked between the 3 groups.

Conclusion: Aquatic therapy has a positive effect on clinical outcomes until 6 months after surgery, but yields little improvements on function or satisfaction at 1 to 2 years follow-up.

Introduction
Stress shielding has received increased attention in research, with higher filling ratios and female gender identified as risk factors. The aim of this study was to investigate the effect of the remaining rotator cuff tendons (RCT) and soft tissue tensioning on stress shielding in uncemented RTSA.

Methods
A prospectively collected database of patients undergoing RTSA between 2017 and 2021 was reviewed. Excluded were patients with tumors, fractures, cemented RTSA, and incomplete radiographic data at 2-year follow-up. Demographic variables included age and gender. Radiographic variables included stress shielding, bone quality (deltoid tuberosity index [DTI]), metaphyseal and distal filling ratios (mFR and dFR), lateralization angle (LSA), and distalization angle (DSA). The number of intact RCT was determined based on available imaging and intraoperative evaluation. The effect of the assessed variables on stress shielding was analyzed with regression analyses. Optimal thresholds were calculated using recursive partitioning.

Results
In 77 consecutive patients (mean age 72 years), RTSA resulted in a mean absolute CS (aCS) of 71 points and a mean relative CS of 98% at 2-year follow-up. The presence of stress shielding, seen in 32 cases (aCS: 70 points), did not affect functional outcome compared to those without stress shielding (aCS: 72 points; p = 0.39). Linear regression analyses identified female gender (p = 0.041), higher dFR (p < 0.001), < 3 intact RCT (p = 0.006), and lower DSA (p = 0.044) as independent risk factors for stress shielding. Age, DTI and LSA had no influence. Cut-off values to prevent stress shielding were > 55° for DSA and < 0.79 for dFR, reducing stress shielding by a factor of 15 when both are met.

Conclusion
In addition to known risk factors such as higher filling ratios and gender, < 3 intact RCT and lower DSA were found to be independent risk factors for stress shielding. This suggests that an intact rotator cuff and an optimal soft tissue tensioning through distalization reduces bone resorption, possibly due to a better tensile load transfer from soft tissue to bone. Lower filling ratios, ideally < 0.79, remain the most important factor. However, additional distalization with a DSA > 55° substantially reduces stress shielding at 2 years, with a 15-fold decrease in occurrence when both thresholds are met.

Introduction: The risk of recurrent defect after arthroscopic rotator cuff repair (ARCR) differs over postoperative time and depends on the severity of the initial tear. Data assessing the most reliable imaging modality for the routine evaluation of tendon integrity after rotator cuff repair is limited. The objective of this study was to identify the accuracy of ultrasound (US) in the routine postoperative evaluation of repaired rotator cuff tendons.

Methods: Between June 2020 and July 2022, we prospectively recruited 310 patients undergoing ARCR from the ARCR_Pred cohort in 9 Swiss orthopaedic centers. All patients underwent routine magnetic resonance imaging (MRI) und US 1 year post-ARCR. Tendon integrity was classified according to Sugaya et al for MRI and a three-staged classification system (intact, partial, complete tear) for US. MRI readings were performed by two independent assessors (orthopaedic surgeon and radiologist). MRI assessments were then regrouped to intact (Sugaya I, II), partial (Sugaya III) and complete retears (Sugaya IV, V). Interobserver reliability for MRI readings was assessed by the Kappa statistics (k). Sensitivity, specificity and accuracy of US imaging to identify recurrent defects were assessed with regards to MRI as reference standard.

Results: Values of k for interobserver reliability of MRI readings were 0.65 for partial and 0.73 for full-thickness tendon defects. While 26 (8%) partial and 54 (17%) full-thickness defects were detected by MRI, 38 (12%) partial and 10 (3%) full-thickness defects were detected by US. Both imaging modalities showed that the number of recurrent defects increased with an increasing tear severity. US had 13.0% (95% CI 9.2% to 16.7%) sensitivity for full repair defects and 26.3% (21.4% to 31.2%) for partial repair defects, when MRI was taken as the reference. The specificity was 98.8% (97.6% to 100%) for full and 88.3% (84.7% to 91.8%) for partial repair defects.

Conclusion: When MRI is considered the reference standard, US has an overall high specificity but poor sensitivity to detect repair failures in routine postoperative imaging one year post-ARCR. The routine use of US imaging after ARCR in asymptomatic patients should therefore be critically scrutinised.

Abstract
Purpose: The purpose of this study was to quantify sleep quality and define its evolution in patients treated for rotator cuff tears with arthroscopic rotator cuff repair (ARCR). Moreover, sleep quality was correlated with patients’ psychological characteristics in terms of depression and anxiety.
Methods: Nine-hundred-and-seventy-three patients (611 men) were enrolled in a prospective multicenter cohort study (ARCR_Pred). Subjective sleep quality (prevalence and level of disturbance), psychological characteristics (PROMIS Sf questionnaire) and functional outcomes were investigated before the operation and prospectively at 6 and 12 months of follow-up. A gender-based analysis was performed as well.
Results: A high prevalence of sleep disturbances was found before ARCR (88.4%), with 59% of the patients complaining of disturbance every night. Sleep disturbances progressively improved at 6 months (37.2%) and 12 months (22.0%). Also, nocturnal pain (frequency of night disturbed by pain) progressively improved from a prevalence of 94.3% to 62.4%, and then 37.9%. Anxiety and depression were found to be related to worse sleep quality and nocturnal pain. On the other hand, the post-op improvement led to a decrease of anxiety and depression levels passing from 50.1 and 51.4 points at baseline to 45.0 and 45.4 at 12 months, respectively. Women had statistically worse sleep quality at 6 and 12 months when compared to men, with a 27% disturbance prevalence compared to the 19% retrieved in the men at 12 months.
Conclusions: Rotator cuff tears cause a high prevalence of sleep disturbance and nocturnal pain, which progressively resolves after an arthroscopic tendon repair. Women have a higher risk than men to develop these problems, and clinicians should take this into account when planning the rehabilitation program for their patients.

Background:
The severity of fatty infiltration (FI) predicts the treatment outcome of rotator cuff tears. The purpose of this investigation was to quantitatively analyze supraspinatus (SSP) muscle FI and volume at the initial presentation and after a 3-month minimum of conservative management. We hypothesized that progression of FI could be predicted with initial tear size, FI, and muscle volume.
Methods:
Seventy-nine shoulders with rotator cuff tears were prospectively enrolled, and 2 magnetic resonance imaging (MRI) scans with 6-point Dixon sequences were acquired. The fat fraction within the SSP muscle was measured on 3 sagittal slices, and the arithmetic mean was calculated (FISSP). Advanced FISSP was defined as ≥8%, pathological FISSP was defined as ≥13.5%, and relevant progression was defined as a ≥4.5% increase in FISSP. Furthermore, muscle volume, tear location, size, and Goutallier grade were evaluated.
Results:
57 shoulders (72.1%) had normal FISSP, 13 (16.5%) had advanced FISSP, and 9 (11.4%) had pathological FISSP at the initial MRI scan. 11 shoulders (13.9%) showed a ≥ 4.5% increase in FISSP at 19.5±14.7 months, and 17 shoulders (21.5%) showed a ≥ 5mm3 loss of volume at 17.8±15.3 months. 5 tears (7.1%) with initially normal or advanced FISSP turned pathological. These tears, compared with tears that were not pathological, had significantly higher initial mediolateral tear size (24.8 vs. 14.3 mm; p=0.05), less volume (23.5 vs. 34.2 mm3; p=0.024), more FISSP (9.6% vs. 5.6%; p=0.026), and increased progression of FISSP (8.6% vs. 0.5%; p < 0.001). An initial mediolateral tear size of ≥20 mm yielded a relevant FISSP progression rate of 81.8% (odds ratio [OR], 19.0; p < 0.001). Progression rates of 72.7% were found for both initial FISSP of ≥9.9% (OR, 17.5; p < 0.001) and an initial anteroposterior tear size of ≥ 17 mm (OR, 8.0; p = 0.003). The correlation between FISSP progression and the time between MRI scans was weak positive (ρ = 0.31).
Conclusions:
Three risk factors for relevant FI progression, quantifiable on the initial MRI, were identified: ≥ 20mm mediolateral tear size, ≥ 9.9% FISSP, and ≥17-mm anteroposterior tear size. These thresholds were associated with a higher risk of tear progression: 19 times higher for ≥ 20mm mediolateral tear size, 17.5 times higher for ≥ 9.9% FISSP, and 8 times higher for ≥ 17mm anteroposterior tear size. The presence of all 3 yielded a 91% chance of ≥ 4.5% progression of FISSP within a mean of 19.5 months.

Introduction:
Comprehensive standardized recording of adverse events (AE) is essential for personalized decision-making in arthroscopic rotator cuff repair (ARCR). Relevant events were defined in a "core event set" (CES). The objectives of this study were to 1) describe the AE risks observed in a large Swiss multicenter ARCR cohort, 2) evaluate patient-reported events and 3) investigate variability between clinics.

Methods:
Between 06/2020 and 11/2021, 973 primary ARCR patients were prospectively enrolled at 19 orthopedic centers and followed up for 24 months. Events local to the operated shoulder were reported by patients, surgeons and other project staff. They were documented using a structured CES and classified by severity in 5 grades from I (low severity) to V (dead). All events were reviewed by three experienced shoulder surgeons. Patients and surgeons independently re-assessed AE severity on a VAS scale (0-100). Complication risks (CR) were calculated stratified by rotator cuff tear severity. The distributions of severity ratings were compared between patients and surgeons. CRs across clinics were explored.

Results:
A total of 356 local AEs were documented in 322 patients within 2 years after ARCR, of which 45% and 37% were reported by all project staff and patients only, respectively. The CR for postoperative local adverse events (plAE) were 22.4%, 28.6% and 31.7% at 6, 12 and 24 months, respectively, with 92% of patients experiencing only one event. Patients with partial tears, single full-thickness tears, multiple tears with one full-thickness tear, and massive tears had 39.5%, 33.7%, 31.5% and 27.8% CR within 2 years, respectively. The most incident AEs were persisting or worsening pain (CR 11.7%), symptomatic shoulder stiffness (8.0%) and symptomatic recurrent rotator cuff defects (4.9%). Severity classification of plAEs revealed 61% grade I, 25% grade II, 13% grade III, 1% grade IV. Median severity assessment on VAS by patients, operating surgeons and non-operating surgeons were 60, 22 and 31, respectively (p < 0.001). The CRs of plAE ranged from 15.4% to 44.8% across clinics.

Conclusion:
About one third of ARCR patients experienced a local event, the majority showing low severity as classified by surgeons; patients however rated their events more severely than surgeons. Large variability of AE occurrence across clinics was observed. Clinic, surgeon and patient profiles associated with AE occurrence should be further explored.