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Objective: The study aimed to investigate the effects of the level of contraction during isometric shoulder abduction at different abduction angles on muscle thickness and stiffness of the shoulder girdle in asymptomatic individuals. Design: Measurement properties study. Setting: Biomechanics and motion analysis lab. Participants: Twenty individuals volunteered to participate in this study. Main Outcome Measure: The subjects were tested for morphological and mechanical properties, expressed by thickness and stiffness of the supraspinatus tendon and muscle, and upper trapezius muscle. Moreover, acromiohumeral distance was also evaluated using B-mode ultrasound and shear-wave elastography. Intervention: The thickness and stiffness of the supraspinatus and upper trapezius muscle were assessed at 3 angles of abduction (0°, 60°, and 90°) and 3 levels of contraction (0%, 10%, and 20% of the maximal voluntary isometric contraction) using ultrasonography with shear-wave imaging. Moreover, the acromiohumeral distance was measured to establish the occupation ratio during passive movement. Results: The supraspinatus and upper trapezius muscle thickness and stiffness were significantly greater at 60° shoulder abduction compared with 0°, and 90° compared with 60°, as well as significantly greater at 20% maximal voluntary isometric contraction compared with 0% and 10% maximal voluntary isometric contraction. Thickness and stiffness were significantly greater in the supraspinatus compared with the upper trapezius muscle at all 3 angles of shoulder abduction for all 3 level of contractions. The acromiohumeral distance decreased significantly from 0° to 60° and from 60° to 90°. Conclusion: Morphological and mechanical properties of the supraspinatus and upper trapezius muscles depended on the relative level of muscle contraction and the angle of shoulder abduction. [ABSTRACT FROM AUTHOR]

Context: The aim of this study was to investigate the effects of 8-week ballistic-strength-training program using a validated specific throwing device (ie, Arm/Shoulder Specific Strength Device), on isokinetic shoulders' rotation muscle-torques and ratios as well as range of motion in team handball players. Design: A repeated-measures experimental design with a randomized controlled trial was used. Methods: Twenty-six high-level competitive male U-19 team handball players were randomly assigned into training (TG, n = 15) and control (n = 11) groups. The TG undertook a twice a week for 8-week periodized throws program with an individually predetermined optimal load. The program incorporated shackled eccentric and concentric exercises using the Arm/Shoulder Specific Strength Device. Peak torques, functional, and conventional ratios for both arms at different angular velocities (60°·s−1, 180°·s−1, and 300°·s−1) were assessed over time and between groups, using an isokinetic dynamometer. Results: A significant improvement for TG (P <.01; d = 1.13 [moderate]; +20.2%) of the concentric peak torques for dominant arm in external rotation was observed at 300°·s−1. Significant (P <.05–.01) increases were also noted for nondominant arm at the 3 studied angular velocities. In addition, 300°·s−1 eccentric peak torques of the dominant arm and nondominant arm have significantly improved for both external and internal rotations (P <.05; d =.99 [moderate] and d = 1.21 [large]; +15.7% and + 17.9%, respectively) with small changes at the other angular assessed velocities. Posttraining, TG's dominant arm showed significant improvements (P <.05–.01) in functional and conventional ratios at all velocities. Notably, significant differences (P <.05–.01) were observed at 60°·s−1 and across all velocities when comparing the TG with the control group. TG showed significant increase for internal rotation and external rotation shoulder range of motions (P <.05; d = 1.22–1.27 [large]), +5.0% and +7.7%, respectively). Conclusions: The specific 8-week throwing training program on the Arm/Shoulder Specific Strength Device showed significant performance improvements in almost all assessed isokinetic concentric and eccentric peak torques as well as internal and external range of motion increase for both arms while ensuring rotator cuff torque ratios and shoulder mobility in team handball real sport-specific condition. [ABSTRACT FROM AUTHOR]

BACKGROUND: To prospectively evaluate ultrasound backscatter coefficients (BSCs) of the supraspinatus and infraspinatus muscles and compare with Goutallier classification on magnetic resonance imaging (MRI). METHODS: Fifty-six participants had shoulder MRI exams and ultrasound exams of the supraspinatus and infraspinatus muscles. Goutallier MRI grades were determined and BSCs were measured. Group means were compared and the strength of relationships between the measures were determined. Using binarized Goutallier groups (0-2 versus 3-4), areas under the receiver operating characteristic curves (AUROCs) were calculated. The nearest integer cutoff value was determined using Youdens index. RESULTS: BSC values were significantly different among most Goutallier grades for the supraspinatus and infraspinatus muscles (both p

BACKGROUND: The impact of early glenohumeral osteoarthritis (GHOA) on clinical outcomes after rotator cuff repair (RCR) remains unclear. The magnetic resonance imaging (MRI)-based Shoulder Osteoarthritis Severity (SOAS) score is a comprehensive approach to quantifying glenohumeral degeneration. PURPOSE: To investigate the association between SOAS scores and changes in American Shoulder and Elbow Surgeons (ASES) scores in patients who underwent RCR. STUDY DESIGN: Cohort study; Level of evidence, 3. METHODS: Two reviewers independently analyzed the preoperative MRI scans of 116 shoulders and assigned SOAS scores. Spearman correlation was used to calculate the association of mean SOAS scores with patient demographic characteristics and change in ASES scores over the 2-year follow-up period (ΔASES). Multivariate regression analysis was performed between the independent variables of patient age, sex, body mass index, and significant SOAS score components as determined by univariate analysis, with the dependent variable being ΔASES. Significance was defined as P < .05 for univariate analysis and P < .0125 after application of the Bonferroni correction for multivariate analysis. RESULTS: The mean ASES scores were 55.8 ± 18.6 preoperatively and 92.1 ± 12.1 at 2 years postoperatively. The mean preoperative SOAS score was 15.2 ± 7.1. On univariate analysis, the total SOAS score was positively correlated with patient age (r S = 0.41; P < .001), whereas ΔASES was negatively correlated with patient age (r S = -0.27; P = .0032). Increasing SOAS subscores for supraspinatus/infraspinatus tear size (r S = -0.28; P = .024), tendon retraction (r S = -0.23; P = .015), muscle atrophy (r S = -0.20; P = .034), paralabral ganglia (r S = -0.23; P = .015), and cartilage degeneration (r S = -0.21; P = .024) were negatively correlated with ΔASES. A negative correlation was found between increasing total SOAS score and ΔASES (r S = -0.22; P = .016). On multivariate analysis, increasing supraspinatus/infraspinatus tear size was significantly and negatively correlated with ΔASES (β = -3.3; P = .010). CONCLUSION: Increasing the total SOAS score was predictive of less improvement in ASES scores at 2 years postoperatively. On univariate analysis, SOAS subscores with the strongest negative correlations with ΔASES scores included tear size, muscle atrophy, tendon retraction, paralabral ganglia, and cartilage wear. On multivariate analysis, only tear size was significantly associated with a lower change in the ASES score.

Shoulder pain is a complex, prevalent problem that is multifactorial in nature. While there are many potential causes, one common suspect is the rotator cuff musculature. The purpose of the present study was to induce pain in the supraspinatus muscle of healthy subjects and observe the resulting changes in muscle activity. Eight muscles on 23 subjects were assessed using electromyography: anterior, middle, and posterior deltoid; pectoralis major; upper trapezius; latissimus dorsi; serratus anterior; supraspinatus; and infraspinatus. It was hypothesized that the rotator cuff muscles would display reduced activity during pain, and that reductions in activity would remain after the pain had dissipated. Both of the rotator cuff muscles measured did indeed display reduced activity in a majority of the dynamic, isometric, and maximal contractions. Many of those reductions remained after the pain had subsided. [ABSTRACT FROM AUTHOR]

Objective: To assess the mechanism of supraspinatus tendinopathy induced by type 2 diabetes mellitus (T2DM) in rats using untargeted metabolomics analysis. Methods: The liquid chromatography-mass spectrometry (LC-MS)-based untargeted metabolomics approach was used to screen tendon biomarkers of supraspinatus tendinopathy in rats with T2DM. Seventy-eight Sprague-Dawley rats were divided into normal group (NG) and T2DM groups. Rats in T2DM groups were divided into 12-week (T2DM-12w), and 24-week (T2DM-24w) subgroups according to the time point of the establishment of the T2DM rat model. Histological evaluation (modified Bonar score) and biomechanical testing were used to analyze the adverse effects of type 2 diabetes on the tendon of the supraspinatus muscle in rats.Three comparable groups were set up, including T2DM-12w group vs. NG, T2DM-24w group vs. NG, and T2DM-24w group vs. T2DM-12w group. Differentially expressed metabolites (DEMs) in the supraspinatus tendons in the three groups of rats were analyzed using LC-MS, and data were analyzed using multivariate statistical methods to screen potential biomarkers. The DEMs included in the intersection of the three groups were identified as those associated with the development of diabetic supraspinatus tendinopathy, and trend analysis and pathway topology analysis were performed. Results: With the progression of diabetes, the tendinopathy of the supracinatus muscle of diabetic rats gradually intensified, mainly manifested as inflammatory reactions, disordered collagen fibers, fat infiltration, and increased modified Bonar score. The intersection of DEMs among the three comparable groups was resulted in the identification of 10 key DEMs, in which melezitose and raffinose showed a continuous increasing trend with the prolongation of disease course. By pathway topology analysis, 10 DEMs (P < 0.01) were mainly associated with the pathways of galactose metabolism, which could be involved in the development of diabetes-induced supraspinatus tendinopathy. Conclusion: T2DM causes tendinopathy of the supraspinatus muscle in rats. 10 key DEMs obtained by untargeted metabolomics assay suggested that the development of diabetes-induced supraspinatus tendinopathy was associated with changes in metabolic pathways, such as galactose metabolism. melezitose and raffinose hold promise as a biomarker for disease discrimination and/or disease indication in diabetic supraspinatus tendinopathy. [ABSTRACT FROM AUTHOR]

Background: Subacromial balloon spacer implantation (SBSI) attempts to decrease glenohumeral joint (GHJ) pain and improve function in patients with an irreparable rotator cuff tear (RCT) and minimal osteoarthritis. Between 12 and 26 weeks post-SBSI, gradual implant resorption may create a "balloon dip" that decreases GHJ function and increases pain. This retrospective cohort study attempted to delineate shoulder function, active mobility, strength, pain, and functional task impairment during the "balloon dip" period. Materials and methods: Sixty-five consecutive patients (55.9 ± 7 years of age, 42 men) with an irreparable RCT treated by the same fellowship-trained shoulder surgeon participated in this study. Outcome measurements pre-SBSI, during Phase I (early pain control ≤ 3 weeks post-SBSI), Phase II (early rehabilitation > 3–11 weeks post-SBSI), Phase III (advanced rehabilitation-early balloon resorption > 11–16 weeks post-SBSI), Phase IV (early strength training > 16–24 weeks post-SBSI), and Phase V (advanced strength training > 24 weeks post-SBSI) included the American Shoulder and Elbow Society (ASES) score for perceived bilateral shoulder function, visual analog scale (VAS) surgical shoulder pain score, active mobility, and shoulder manual muscle strength testing (p ≤ 0.05). Results: The mean final follow-up time was 40 weeks (range = 24.1–89.7 weeks). The surgical shoulder had higher ASES scores at Phase V than pre-SBSI. Surgical shoulder pain was less during Phase V than pre-SBSI. The surgical shoulder had greater flexion during Phase V than at Phase II or pre-SBSI, and greater external rotation (adducted) during Phases V-III than pre-SBSI. Peak shoulder internal rotation to level 12 (thoracic spinous process #10) occurred during Phase V. Peak shoulder flexor, external rotator, and internal rotator strength occurred during Phase V. During Phase I, most subjects were unable to sleep on their surgical shoulder, wash their back/do up their bra, reach a high shelf, or lift 10-lbs overhead. Tasks that were impaired during the "balloon dip" (between Phase III and V) were lifting 10-lbs overhead, reaching a high shelf, and doing normal work. By the end of Phase V, however, most subjects could perform each task with minimal or no difficulty. Conclusion: Surgical shoulder function improved and pain decreased, however, specific perceived functional task impairments remained. During the "balloon dip" phase, the perceived ability to lift 10 lbs above shoulder level, to reach a high shelf, and to do usual work activities were the most impaired tasks. [ABSTRACT FROM AUTHOR]

The rotator cuff, comprising the subscapularis, supraspina-tus, infraspinatus, and teres minor muscles, plays a crucial role in stabilizing the glenohumeral joint by securing the head of the humerus within the glenoid cavity of the scapula. The tendinous insertions of these muscles generate tension within the capsule, enhancing joint stability during muscular activity. The rotator cuff is susceptible to damage from disease, injury, or trauma, which can result in tears or ruptures of one or more tendons. The evaluation of the infraspinatus muscle and tendon is vital for diagnosing and managing various shoulder pathologies. Accurate imaging to determine the specific muscle involvement and injury severity significantly impacts treatment decisions. Diagnostic musculoskeletal ultrasound (MSK-US) has emerged as a valuable tool for assessing the infraspinatus muscle and tendon, offering real-time, dynamic assessment capabilities essential for precise diagnosis and effective rehabilitation planning. This article reviews the utility and advantages of MSK-US in evaluating the infraspinatus muscle and tendon, emphasizing technique specifics, diagnostic accuracy, and comparative efficacy against other imaging modalities. It details a systematic approach to the ultrasound examination technique for the infraspinatus, including patient positioning and identification of common pathologies such as tears, tendinopathy, and calcifications. With recent advancements in transducer strength, image resolution, and operator training, ultrasound serves as an excellent alternative imaging modality for diagnosing rotator cuff tears. This article aims to equip rehabilitation professionals with a comprehensive understanding of MSK-US as a diagnostic tool for the infraspinatus, promoting more precise diagnosis, treatment planning and improved patient outcomes. [ABSTRACT FROM AUTHOR]

Purpose Methods Results Conclusions Level of Evidence To compare functional outcomes such as muscle strength, neuromuscular control and patient‐reported outcomes (PROs) between patients with healed rotator cuffs and those with retears after arthroscopic rotator cuff repair (RCR).One hundred and nine patients who underwent arthroscopic RCR were included (85 in the healed group, 24 in the retear group). Shoulder muscle strength and neuromuscular control index (acceleration time [AT]) were evaluated using an isokinetic device. PROs were assessed using the pain visual analogue scale (VAS), Simple Shoulder Test (SST), American Shoulder and Elbow Surgeons (ASES) and University of California at Los Angeles (UCLA) scores. Continuous variables were compared using independent t tests. Multiple linear regression analysis was used to identify the influence of the predictor variables on the dependent variable.The muscle strength and ATs for external rotators (ERs), internal rotators (IRs) and forward flexors as well as PROs including VAS, SST and ASES scores, were not significantly different between the two groups pre‐ and postoperatively (n.s.). Multiple linear regression analysis revealed that postoperative ATs for the IRs (p = 0.006) and ERs (p = 0.028) in the operated shoulders were closely associated with the postoperative UCLA score.Compared with the healed group after arthroscopic RCR, the retear group had no clinically relevant differences in muscle strength, ATs and PROs, including VAS, SST, ASES and UCLA scores. However, postoperative ATs for IRs and ERs in the operated shoulders were a significant predictor of postoperative UCLA scores. Therefore, clinicians and therapists need to be aware of the importance of neuromuscular control in patients who have undergone arthroscopic RCR and prioritize therapeutic exercises to restore neuromuscular control.Level III. [ABSTRACT FROM AUTHOR]

This study aimed to morphologically and histologically examine whether pig is useful as models for rotator cuff tear (RCT). The morphology of the scapula and humerus bones was evaluated by taking X-ray and three-dimensional computed tomography (3D CT) scans of the right shoulders of five female pigs (age: 4 months). The rotator cuff (RC) footprint at the humeral insertion of these was observed and its shape was measured. Next, they underwent general anesthesia and an acute rotator cuff tear/rotator cuff repair (RCT/RCR) model was created using a deltoid split approach. Four weeks after surgery, the animals were euthanized, the shoulder joints were harvested, and the repaired RC was evaluated by hematoxylin and eosin staining and toluidine blue staining. The scapula of the pig had a vestigial acromion, in contrast to that in humans. The supraspinatus and infraspinatus tendons were connected so as to overlap each other and attached to the postero-superior part of the greater tuberosity. These tendons were located extra-articularly, separate from the joint capsule. The average antero-posterior length of the foot print was 17.4 ± 0.7 mm on the medial margin and 19.1 ± 2.2 mm on the lateral margin. The maximum medial-to-lateral width of it was 5.1 ± 0.5 mm. In all RCT/RCR models at 4 weeks after surgery, the repaired RC compound tendon was visually confirmed to be continuous with the footprint. Histologically, it was confirmed that regeneration of the four-layer structure of the bone-tendon junction had occurred. Porcine supraspinatus and infraspinatus attachment to the greater tuberosity have a structure similar to that of sheep and dogs, which is advantageous for creating the RCT/RCR model. It might be used for future in vivo studies of shoulder joint diseases. Pigs could potentially serve as a viable model for rotator cuff tears. [ABSTRACT FROM AUTHOR]

Background: Rotator cuff repair is widely recognized as one of the most painful orthopedic surgeries, yet postoperative pain management in these patients is often underexplored. This study aimed to explore the relationship between pain outcomes and functional recovery six months after arthroscopic rotator cuff repair (ARCR), with a focus on the role of different pain coping mechanisms as mediators. Methods: This study included 83 patients that underwent rotator cuff repair. Pain levels were assessed using the Brief Pain Inventory (BPI-SF), while shoulder function was evaluated using the Oxford Shoulder Score (OSS). Coping strategies, including self-statements, ignoring pain, distraction, and praying, were examined in relation to pain severity and interference and were assessed with the Coping Strategies Questionnaire-Revised (CSQ-R). Simple and parallel mediation analyses were performed using the PROCESS macro to assess the mediating effects of coping mechanisms on the relationship between pain intensity, pain interference, and postoperative OSS. Results: Post-surgery, patients showed a significant improvement in OSS (from 29 ± 9 to 42 ± 6). At six months, 24% of patients reported chronic postsurgical pain (CPSP), defined as a pain severity score of 3 or higher. Correlation analyses revealed that OSS was negatively associated with pain catastrophizing (r = −0.35, p < 0.01) and praying (r = −0.28, p < 0.01). OSS was significantly negatively associated with pain severity (r = −0.54; p < 0.01) and pain interference (r = −0.51, p < 0.01). Mediation analysis demonstrated that coping self-statements significantly mediated the relationship between pain interference and shoulder function (a*b = 0.5266 (BootSE = 0.2691, 95% CI [0.1010, 1.1470]), emphasizing the important role of cognitive strategies in supporting recovery outcomes. Conclusion: Patients engaging in adaptive coping strategies, particularly coping self-statements, reported better functional outcomes. The findings underscore the importance of targeted interventions focusing on effective pain coping mechanisms to improve recovery post-ARCR. [ABSTRACT FROM AUTHOR]

Rotator cuff tears (RCT) are the most common cause of shoulder pain among adults. "Rotator cuff" refers to the four muscles that cover the shoulder joint: supraspinatus, infraspinatus, subscapularis, and teres minor. These muscles help maintain the rotational movement and stability of the shoulder joint. RCT is a condition in which one or more of these four muscles become ruptured or damaged, causing pain in the arms and shoulders. RCT results from degenerative changes caused by chronic inflammation of the tendons and consequent tendon tissue defects. This phenomenon occurs because of the exhaustion of endogenous tendon stem cells. Tendon regeneration requires rejuvenation of these endogenous tendon stem/progenitor cells (TSPCs) prior to their growth phase. TSPCs exhibit clonogenicity, multipotency, and self-renewal properties; they express classical stem cell markers and genes associated with the tendon lineage. However, specific markers for TSPC are yet to be identified. In this review, we introduce novel TSPC markers and discuss various strategies for TSPC reprogramming. With further research, TSPC reprogramming technology could be adapted to treat age-related degenerative diseases, providing a new strategy for regenerative medicine. [ABSTRACT FROM AUTHOR]

The success of rotator cuff tendon repair relies on both tendon healing and muscle recovery. The objective of this descriptive study was to investigate the regenerative potential of the supraspinatus muscle in rotator cuff tear conditions by quantifying the expression of Pax7, MyoD, and myogenin, basic factors that regulate myogenesis. Muscle biopsies were collected from thirty-three patients aged 34 to 73 years who underwent surgery for a rotator cuff tear affecting the supraspinatus muscle. Among these patients, twenty-seven percent were women, and the age of the lesions ranged from 2 to 72 months post-initial trauma. Biopsies were harvested from the supraspinatus muscle at the end closest to the tendon, and control biopsies were harvested from the ipsilateral deltoid muscle. The densities of immunohistochemically stained Pax7+, MyoD+, and myogenin+ nuclei/mm2 were used to estimate the myogenic potential of the muscle. Adjustments were made for patient age and lesion age. We found increased density of MyoD+ and myogenin+ cells in supraspinatus muscles compared to deltoid muscles (p < 0.001 and p = 0.003, respectively). Regression analyses that combined the density of positive nuclei with patient age showed a continuous increase in Pax7 with age but also a reduction of MyoD and myogenin in older patients. When combined with lesion age, there was a decline in the density of all myogenic markers after an initial rise. Pax7 density continued to be higher in supraspinatus compared to the deltoid muscle, but the density of MyoD and myogenin terminally dropped to a density lower than in the deltoid. Our findings suggest that the supraspinatus muscle in tear conditions showed signs of initial activation of muscle regeneration. When compared to the unaffected deltoid muscle, an apparent reduction in capacity to progress to full muscle fiber maturity was also demonstrated. This pattern of inhibited myogenesis seemed to increase with both patient age and lesion age. Our results on muscle regenerative capacity indicate that younger patients with rotator cuff tears have better chances of muscle recovery and may benefit from early surgical reconstruction. [ABSTRACT FROM AUTHOR]

Objective: To retrospectively evaluate clinical outcomes, including function and pain, of patients after our all arthroscopic "whole layer" rotator cuff repair technique with simultaneous biceps tenodesis procedure; factors influencing results were also evaluated. Given the frequent association of rotator cuff tear with long head of biceps lesion and the need for effective combined treatment strategies, this study aims to evaluate the efficacy of our technique and compare it with established methods. We hypothesized that our technique would significantly improve function and reduce pain in patients with rotator cuff tears and biceps pathology. Methods: This is a retrospective study that included patients older than 20 years who underwent all arthroscopic "whole layer" rotator cuff repair technique with simultaneous biceps tenodesis procedures for concomitant rotator cuff tear and long head biceps pathology, from 2016 to 2020. Patients were evaluated preoperatively and at a minimum of 2 years of follow‐up using the American Shoulder and Elbow Surgeons (ASES) and visual analogue scale (VAS) scores paired t‐tests were used for analysis and statistical significance was set at p < 0.05(two‐tailed). The satisfaction rate and complications were also evaluated. Results: After an average follow‐up of 2.3 years, 118 patients demonstrated significant improvement in both the ASES score (from 36.13 to 95.01, p < 0.001) and VAS score (from 6.81 to 0.89, p < 0.001). Ninety‐four percent of the patients reported satisfaction with the surgical outcome. No complications related to Popeye deformity, biceps cramping pain, or ipsilateral shoulder reoperation were observed. Factors such as age, sex, body mass index (BMI), smoking status, alcohol consumption, hypertension, and diabetes did not influence the results. Patients showed significant improvement in both the ASES and VAS scores (p < 0.001). Conclusion: At a mean follow‐up time of 2.3 years, the all arthroscopic "whole layer" rotator cuff repair technique with simultaneous biceps tenodesis is a therapeutic and efficient procedure. The procedure revealed a satisfactory functional outcome, reduced pain, and minimal complications and reoperations. [ABSTRACT FROM AUTHOR]

Background: It is unclear whether the use of concomitant acromioplasty during rotator cuff repair (RCR) improves clinical outcomes and whether the outcomes are affected by acromial type. Purpose: To perform a systematic review of randomized controlled trials comparing clinical outcomes of RCR with and without acromioplasty, with a subanalysis of outcomes based on acromial type. Study Design: Systematic review; Level of evidence, 2. Methods: A systematic review was conducted according to the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines by searching PubMed, the Cochrane Library, and Embase to identify randomized controlled trials that directly compared outcomes between RCR with versus without acromioplasty. A subanalysis was performed on the studies that provided outcomes based on acromial type. The search phrase used was rotator cuff repair (acromioplasty OR subacromial decompression) randomized. Patients were evaluated based on retear rate, reoperation rate, and patient-reported outcomes (PROs). Results: Application of inclusion criteria yielded 5 studies (2 studies were level 1, and 3 studies were level 2) including a total of 409 patients, with 211 patients undergoing RCR alone (group A) and 198 patients undergoing RCR with acromioplasty (group B). The mean patient age was 58.5 and 58.3 years in groups A and B, respectively. The mean follow-up time was 52.9 months, and the overall percentage of male patients was 54.1%. The rotator cuff tear size was 20.7 mm and 19.8 mm for groups A and B, respectively. No significant differences were found between groups for any of the PROs at final follow-up. Overall retear rates did not significantly differ between groups based on acromial type. Between 2 studies that measured reoperation rate, a significantly higher reoperation rate was found for the nonacromioplasty group (15%) versus the acromioplasty group (4.1%) (P =.031). One of these studies found that 5 of 9 patients (56%) with a type III acromion in the nonacromioplasty group underwent reoperation compared with 0 of 4 patients with a type III acromion in the acromioplasty group. Conclusion: There is some evidence that acromioplasty during RCR reduces the risk for later reoperation. This may be particularly true for patients with type III acromions, although further studies with larger sample sizes are needed to corroborate these data. [ABSTRACT FROM AUTHOR]

Partial-thickness rotator cuff tears are a common cause of pain and disability and are central to developing full-thickness rotator cuff tears. However, limited knowledge exists regarding the alterations to the mechanical environment due to these lesions. Computational models that study the alterations to the mechanical environment of the supraspinatus tendon can help advance clinical management to avoid tear progression and provide a basis for surgical intervention. In this study, we use three-dimensional validated finite element models from six intact specimens to study the effects of low- and high-grade tears originating on the articular and bursal surfaces of the supraspinatus tendon. Bursal-sided tears generally had a lower failure load, modulus, and strain than articular-sided tears. Thus, caution should be taken when managing bursal-sided tears as they may be more susceptible to tear progression. [ABSTRACT FROM AUTHOR]

Chronic rotator cuff (RC) injuries can lead to a degenerative microenvironment that favors chronic inflammation, fibrosis, and fatty infiltration. Recovery of muscle structure and function will ultimately require a complex network of muscle resident cells, including satellite cells, fibro‐adipogenic progenitors (FAPs), and immune cells. Recent work suggests that signaling from adipose tissue and progenitors could modulate regeneration and recovery of function, particularly promyogenic signaling from brown or beige adipose (BAT). In this study, we sought to identify cellular targets of BAT signaling during muscle regeneration using a RC BAT transplantation mouse model. Cardiotoxin injured supraspinatus muscle had improved mass at 7 days postsurgery (dps) when transplanted with exogeneous BAT. Transcriptional analysis revealed transplanted BAT modulates FAP signaling early in regeneration likely via crosstalk with immune cells. However, this conferred no long‐term benefit as muscle mass and function were not improved at 28 dps. To eliminate the confounding effects of endogenous BAT, we transplanted BAT in the "BAT‐free" uncoupling protein‐1 diphtheria toxin fragment A (UCP1‐DTA) mouse and here found improved muscle contractile function, but not mass at 28 dps. Interestingly, the transplanted BAT increased fatty infiltration in all experimental groups, implying modulation of FAP adipogenesis during regeneration. Thus, we conclude that transplanted BAT modulates FAP signaling early in regeneration, but does not grant long‐term benefits. [ABSTRACT FROM AUTHOR]

Objective: Transcatheter arterial embolization (TAE) is a novel minimally invasive therapy for painful tendinopathy in patients with pain refractory to conservative management. The purpose of this study was to evaluate evidence on the efficacy of TAE for tendinopathy related pain. Materials and Methods: Using Embase, PubMed, and Web of Science, a systematic review and meta-analysis was performed to identify studies evaluating TAE for painful tendinopathy. The primary outcome measure was change in pain scale score at 6 months. A Ratio of Means (ROM) was used to compare the effect size post treatment as compared to baseline. The Visual Analog Scale (VAS) was used as the metric for comparison. Results: After screening titles, abstracts, and the full text, 5 studies met inclusion criteria. A total of 97 tendinopathy embolization procedures performed in 74 patients were included. Patients who underwent TAE demonstrated declines in VAS ROM at 1 day 0.53 [95% CI 0.31,0.88], 1 week (0.51 [95% CI 0.32,0.79]), 1 month (0.45 [95% CI 0.29, 0.71]), 3–4 months (0.33 [95% CI 0.22,0.48]), and 6 months following embolization (0.18[95% CI 0.13,0.26]), respectively. Discussion: TAE provides substantial short-term reductions in pain scores for patients suffering with refractory tendinopathy related pain of the rotator cuff, elbow extensor and flexor, Achilles, and patellar tendons. [ABSTRACT FROM AUTHOR]

The prevalence of asymptomatic shoulder pathology has been shown to be high on both ultrasound and magnetic resonance imaging (MRI). The most common shoulder pathologies identified in asymptomatic, non‐athlete individuals include rotator cuff pathology, acromioclavicular (AC) joint pathology, labral tears, subacromial bursitis, and calcific tendinitis. The data in the current literature suggest that asymptomatic rotator cuff tears are diagnosed on ultrasound and MRI at high rates, suggesting that rotator cuff tears may be considered an age‐related, normal, degenerative change. However, there are data to suggest that the presence of an asymptomatic rotator cuff tear on imaging may predispose a patient to shoulder pain in the future, although the data remain inconclusive. AC joint arthritic changes are also common in older individuals on advanced imaging. Recent studies have reported that labral tears are common in asymptomatic shoulders, although at less frequent rates than in athletes, but more research is required on this topic. In addition, the presence of subacromial bursitis on imaging has not been found to accurately differentiate between symptomatic and asymptomatic shoulders. Finally, calcific tendinitis has been diagnosed asymptomatically, with most individuals remaining asymptomatic. Individuals who did develop pain developed severe pain, although the risk factors for developing symptomatic calcific tendinitis are unclear. In summary, given the high prevalence of shoulder pathology diagnosed on imaging, it is important to not over diagnose or complete an unnecessary workup for an asymptomatic person who is otherwise healthy. [ABSTRACT FROM AUTHOR]

Background The rotator cuff (RC) plays a pivotal role in the performance and health of the shoulder and upper extremity. Blood flow restriction training (BFRT) is a modality to improve strength and muscle hypertrophy with even low-load training in healthy and injured individuals. There is minimal evidence examining its effect proximal to the occluded area, and particularly on the RC. Hypothesis & Purpose The purpose of this case series is to explore the effects of low-load BFRT on RC strength, hypertrophy, and tendon thickness in asymptomatic individuals. Study Design Case series. Methods Fourteen participants with asymptomatic, untrained shoulders were recruited to participate. They performed an eight-week low-load shoulder exercise regimen where BFR was applied to the dominant arm only during exercise. The dependent variables were maximal isometric strength of the shoulder external rotators(ER) and elevators (in the scapular plane in full can position) (FC) measured via handheld dynamometry, cross sectional area (CSA) of the supraspinatus and infraspinatus muscles, and supraspinatus tendon thickness measured via ultrasound imaging (US). Mean changes within and between arms were compared after training using paired t-tests. Cohen's d was used to determine effect sizes. Results All participants were able to complete the BFRT regimen without adverse effects. Mean strength and CSA increased for all variables in both arms, however this increase was only significant (p<0.01) for FC strength bilaterally and CSA for the supraspinatus and infraspinatus on the BFRT side. The effect sizes for increased supraspinatus and infraspinatus CSA on the BFRT side were 0.40 (9.8% increase) and 0.46 (11.7% increase) respectively. There were no significant differences when comparing the mean changes of the BFRT side to the non-BFRT side for strength or muscle CSA. There were no significant changes to supraspinatus tendon thickness. Conclusion These results suggest variability in response of the RC musculature to low-load BFRT in asymptomatic individuals. The potential for a confounding systemic response in the study design makes determining whether low-load BFRT is more beneficial than low-load non-BFRT difficult. The hypertrophy seen on the BFRT side warrants further study. Level of Evidence 4 [ABSTRACT FROM AUTHOR]

Rotator cuff tendinopathy is the most common tendinopathy type with the worst prognosis. Conventional treatments often elicit heterogeneous drug responses due to the diversity of tendinopathy. Hence, this study attempted a classification of 126 diseased tendons into three distinct subtypes with opposite pathogenic mechanisms based on transcriptomic and clinical features. The hypoxic atrophic subtype with white appearance (Hw) exhibits downregulated neovascularization pathways. The inflammatory proliferative subtype with white appearance (Iw) shows a moderate upregulation of inflammatory characteristics. The inflammatory proliferative subtype with red appearance (Ir) exhibits the highest levels of upregulated neovascularization and inflammatory pathways, along with severe joint dysfunction. We then established research models, including subtype-specific simulations in animal models and clinical data analysis. These revealed that glucocorticoid, a controversial commonly used drug, was only effective in treating the Ir subtype. Hence, the tendinopathy subtypes elucidated in this study have significant implications for developing precision treatment of tendinopathy. This study classifies rotator cuff tendinopathy into three distinct subtypes that include a hypoxic atrophic, an inflammatory proliferative with white appearance and an inflammatory proliferative with red appearance subtype. Using both clinical data and animal models, the research reveals that glucocorticoid is only effective in treating the latter inflammatory proliferative subtype that has the highest level of neovascularization. [ABSTRACT FROM AUTHOR]

Introduction: The acromiohumeral center-edge angle (ACEA) is a parameter that can be measured on plain shoulder radiographs and has been found to be associated with increased risk of sustaining a rotator cuff tear. Purpose: The aim of this study was to investigate this association using plain radiographs and to explore its applicability on shoulder magnetic resonance imaging (MRI) in the same patients. Methods: This retrospective study compared 45 patients who underwent rotator cuff repair between September 2021 and April 2022 and 41 patients with normal shoulders. The ACEA was measured by 2 independent observers on anteroposterior radiographs and shoulder MRI. The collected data were analyzed and P values of <.05 were considered statistically significant. Results: The ACEA was found to be higher in patients with rotator cuff tears (23.48° ± 7.11°) when compared with the control group (15.54° ± 4.4°). On shoulder MRI assessment, a higher ACEA was also seen in the rotator cuff tear group (18.93° ± 6.7°) than in the control group (13.79° ± 4.9°). The ACEA measurement on MRI showed strong intrarater reliability (0.965), but weak interrater reliability (0.251). Conclusion: This retrospective study found an association between increased ACEA and risk of rotator cuff tear when measured on plain radiographs. In addition, we found an association between increased ACEA measurement on shoulder MRI and rotator cuff tears, thus suggesting the applicability of ACEA measurement on shoulder MRI. [ABSTRACT FROM AUTHOR]

Background: An umbrella review of meta-analyses was conducted to evaluate the use of platelet-rich plasma (PRP) in arthroscopic surgeries of rotator cuff injury. The effectiveness of leukocyte-poor PRP and leukocyte-rich PRP in the treatment of rotator cuff surgery was also compared. Methods: Web of Science, Embase, PubMed/MEDLINE, and the Cochrane Library were searched from inception to May 2024. Literature screening, quality evaluation, and data extraction were performed according to the inclusion and exclusion criteria. The Jadad decision algorithm was used to ascertain which meta-analysis represented the best evidence. Results: A total of 11 meta-analyses with evidence level ranging from level 1 to 2 were included in this umbrella review. Leukocyte-poor PRP was effective in reducing rotator cuff retear rates, alleviating pain, and increasing Constant scores compared with non-PRP treatments. However, it did not show improvement on the University of California Los Angeles (UCLA) score, the American Shoulder and Elbow Surgeons (ASES) score, and the Simple Shoulder Test (SST) compared with the non-PRP treatment group. Meanwhile, the leukocyte-rich PRP group improved the SST but showed no different results when compared with the non-PRP treatment group. Conclusion: Compared with no use of PRP, leukocyte-poor PRP was able to alleviate postoperative pain, reduce the retear rate, and improve the postoperative Constant score. Leukocyte-rich PRP could effectively enhance postoperative SST outcomes, leading to improvement of patient satisfaction and quality of life. Future researches should prioritize long-term follow-up studies and evaluate the durability of these results. [ABSTRACT FROM AUTHOR]

Rotator cuff tear (RCT) is the primary cause of shoulder pain and disability and frequently trigger muscle degeneration characterised by muscle atrophy, fatty infiltration and fibrosis. Single‐nucleus RNA sequencing (snRNA‐seq) was used to reveal the transcriptional changes in the supraspinatus muscle after RCT. Supraspinatus muscles were obtained from patients with habitual shoulder dislocation (n = 3) and RCT (n = 3). In response to the RCT, trajectory analysis showed progression from normal myonuclei to ANKRD1+ myonuclei, which captured atrophy‐and fatty infiltration‐related regulons (KLF5, KLF10, FOSL1 and BHLHE40). Transcriptomic alterations in fibro/adipogenic progenitors (FAPs) and muscle satellite cells (MuSCs) have also been studied. By predicting cell–cell interactions, we observed communication alterations between myofibers and muscle‐resident cells following RCT. Our findings reveal the plasticity of muscle cells in response to RCT and offer valuable insights into the molecular mechanisms and potential therapeutic targets of RCT. [ABSTRACT FROM AUTHOR]

Background: Rotator cuff tears (RCT) are a common musculoskeletal condition, especially in the aging population. The prevalence of rotator cuff tears varies based on factors like age, occupation, and activity level. In the general population, the prevalence of rotator cuff tears is estimated to be around 20 to 25%. Rotator cuff tears (RCT) have an impact in patients' pain level, shoulder function, sleep disturbance, and quality of life. Primary tendon surgery is in mostly cases necessary. This study aimed to examine if treatment of rotator cuff lesions with implantation of micro-fragmented adipose tissue can improve patients' reported pain and function compared to conventional surgery. Methods: The study is a prospective superiority parallel-group single-center randomized controlled trial including 30 patients between 40 and 69 years of age in Denmark. Patients will be allocated 1:1 ratio to reconstruction of the supraspinatus tendon with an injection of micro-fragmented adipose tissue into the related muscle (stem cell treatment) or the standard of care (SOC), which is conventional surgery. Patients, project assistants, physicians, and outcome adjudicators are not blinded to randomization due to practical constraints. The radiologist and the statistician performing the analysis will be blinded. The primary outcome will be the Oxford shoulder score at 12 months post-surgery. Discussion: This study will assess whether adding micro-fragmented adipose tissue therapy to conventional rotator cuff tear treatment can enhance recovery, accelerate return to daily activities, and improve functional outcomes. The research will also determine if this minimally invasive procedure could be standardized for routine patient care. Trial registration: ClinicalTrials.gov NCT06505135. Registered on July 10, 2024. [ABSTRACT FROM AUTHOR]

One of the most common shoulder injuries is the rotator cuff tear (RCT). The risk of RCTs increases with age, with a prevalence of 9.7 % in those under 20 years old and up to 62 % in individuals aged 80 years and older. In this article, we present first a microwave digital twin prototype (MDTP) for RCT detection, based on machine learning (ML) and advanced numerical modeling of the system. We generate a generalizable dataset of scattering parameters through flexible numerical modeling in order to bypass real-world data collection challenges. This involves solving the linear system as a result of finite element discretization of the forward problem with use of the domain decomposition method to accelerate the computations. We use a support vector machine (SVM) to differentiate between injured and healthy shoulder models. This approach is more efficient in terms of required memory resources and computing time compared with traditional imaging methods. [ABSTRACT FROM AUTHOR]

Purpose: To explore patient experiences of rotator cuff-related shoulder pain, and their views on the role and value of diagnostic shoulder imaging. Materials and methods: Semi-structured interviews were conducted with 20 patients with shoulder pain exploring the impact and management of their shoulder condition, reasons for and experiences of diagnostic imaging, and feelings about and responses to diagnostic imaging findings. Framework analysis was used to analyse the dataset. Results: Five themes were identified [1]: Lived experience and beliefs about pain and movement [2]; Contextualisation of imaging findings by health professionals is more important than the imaging report [3]; Factors influencing whether and when to have imaging [4]; Imaging can identify the actual problem and guide treatment; and [5] Treatment responses and treatment decision making. Conclusion: Patients commonly believe imaging is needed to formulate a diagnosis. There was minimal concern about potential indirect harms that could arise (e.g., inappropriate diagnosis leading to unnecessary treatments). The context of the diagnostic imaging reports (i.e., what needed to be done) was perceived as more important than the exact meaning of the imaging findings. Patients felt that the diagnostic imaging confirmed their existing biomedical beliefs, and these beliefs were not challenged by their healthcare professionals. IMPLICATIONS FOR REHABILITATION: Patients with shoulder pain may believe imaging is necessary for diagnosis and defining treatment yet do not consider potential indirect harms (e.g., unnecessary treatment for findings that are not relevant). Health professionals should ensure patients are aware of imaging limitations and harms and facilitate shared decision-making about whether to have imaging. Health professionals also have an important role in the appropriate contextualisation of imaging findings (i.e., they do not necessarily relate to pain nor guide treatment). [ABSTRACT FROM AUTHOR]

Background: Massive irreparable rotator cuff tears can cause significant shoulder pain and disability. Treatment options include physiotherapy or surgery, with a lack of research comparing treatment options. For physiotherapy there is uncertainty about which patients will have a successful or unsuccessful response to treatment and a lack of consensus on what constitutes the best physiotherapy programme. With these significant gaps in the research, it is challenging for clinicians seeing patients with massive irreparable rotator cuff tears to advise on what is their best treatment pathway. Methods: A three round Delphi study was conducted with expert shoulder physiotherapists and orthopaedic surgeons to gain consensus on the important factors associated with response to physiotherapy in this patient population. Round 1 was an information-gathering round to identify predictors of response to physiotherapy in patients with massive irreparable rotator cuff tears. Rounds 2 and 3 were consensus-seeking rounds on the importance and modifiability of the predictors. Consensus criteria were determined a priori using median, interquartile range, percentage agreement and Kendall's Coefficient of Concordance. Results: Participants were recruited April–October, 2023. 88 experts participated in Round 1 and of these, 70 completed Round 3 (79.54%). In Round 1, content analysis of 344 statements identified 45 predictors. In Round 2, 29 predictors reached consensus as important and 2 additional predictors were identified. In Round 3, of the 31 predictors from Round 2, 22 reached consensus as important and 12 of these reached consensus as modifiable by physiotherapists. Both patient factors and clinician factors from a broad range of domains reached consensus: biomechanical, psychological, social, co-morbidities, communication / healthcare interactions and pain. Conclusions: The results of this Delphi study suggest that clinicians assessing patients with massive irreparable rotator cuff tears should assess across all these domains and target the modifiable factors with interventions. Particular emphasis should be placed on optimising modifiable clinician factors including therapeutic alliance, comprehensive explanation of the condition and collaborative and realistic goal-setting. These in turn may influence modifiable patient factors including patient expectations, engagement with the physiotherapy programme, motivation and self-efficacy thus creating the ideal environment to intervene on a biomechanical level with exercises. [ABSTRACT FROM AUTHOR]

Introduction: Rotator cuff tears (RCTs) are a common source of pain in the shoulder girdle. There is still debate about the optimal treatment for older adults with RCTs. In clinical practice, patients who do not respond well to non-surgical management may still be eligible for operative treatment. In this study, we assessed the outcome of arthroscopic repair of RCTs in patients ≥60 years old. Material and method: A retrospective case series was conducted to include patients who underwent arthroscopic repair of RCTs from 1 January 2018 to 1 January 2021. The study included individuals aged ≥60 years who had radiologically confirmed RCTs (verified by MRI) and clinical findings including sleep-disturbing pain and reduced range of motion. Preoperative treatment included physiotherapy for at least 6 months and one subacromial corticosteroid injection. Results: Fifty-three RCTs were treated during the study period. After exclusion because of incomplete documentation, 45 patients remained. The mean age was 66 years and 80% had isolated supraspinatus tears and 25% had variable degrees of fatty infiltration (Goutallier grade 1-3) on MRI examination with positive tangent sign. There were no surgical site infections and three symptomatic re-ruptures (6%). At follow-up, (71%) reported no remaining sleep-disturbing shoulder pain. Abduction improved from 62° to 122°. Flexion improved from 68° to 135°. This study found that people aged 60 years and older who underwent repair of RCTs showed statistically significant clinical improvement in shoulder flexion and abduction with less sleep-disturbing shoulder pain. These encouraging results may contribute to the existing literature, favoring the choice of surgical treatment for symptomatic RCTs in this age group with failed nonoperative treatment. Conclusion: The arthroscopic repair of RCTs in patients 60 years and older yielded a substantial increase in shoulder flexion and abduction, significantly reducing sleep-disturbing shoulder pain. Postoperative complications were minimal. [ABSTRACT FROM AUTHOR]

Objective By comparing with arthroscopic rotator cuff repair alone, to explore the efficacy and difference of leukocyte poor platelet-rich plasma (LP-PRP) and leukocyte rich platelet-rich plasma (LR-PRP) in arthroscopic rotator cuff repair. Methods Sixty patients with total rotator cuff tear accompanied by arthroscopic rotator cuff repair admitted to the Affiliated Hospital of North China University of Science and Technology from October 2021 to September 2022 were included and randomly divided into control group (n = 20), LP-PRP group (n = 20) and LR-PRP group (n = 20). The control group only received arthroscopic rotator cuff repair. The LP-PRP group was injected with leukocyte poor platelet-rich plasma (LP-PRP) into the sutured torn tendon after the same operation, and the LR-PRP group was injected with leukocyte rich platelet-rich plasma (LR-PRP) into the sutured torn tendon after the same operation. The postoperative rehabilitation training plan of the three groups was the same, and the postoperative follow-up and evaluation were conducted for 1 year. It included pain score (VAS score), shoulder joint function score (CMS, UCLA, ASES score), retear rate and related complications. Results All patients were followed up. (1) VAS score: Compared with the LR-PRP group and the control group, the results were statistically significant only at 1,3 and 6 weeks after surgery (P < 0.05) ; There was no statistical significance between the LR-PRP group and the control group at 1 week, 3 weeks, 6 weeks, 3 months, 6 months and 12 months after surgery(P > 0.05). (2)CMS, UCLA and ASES scores: There were no significant differences between the LP-PRP group and the LR-PRP group at 3 months, 6 months and 12 months after surgery(P > 0.05); Compared with LP-PRP group and LR-PRP group, there were significant differences in each follow-up time point of control group (P < 0.05). (3) Retear rate: In the LP-PRP group, there was 1 retear in the LR-PRP group (tear rate 5%), and 3 in the control group (tear rate 15%). There was no statistically significant difference between the three groups (P > 0.05). (4) There were no postoperative complications in 60 patients. Conclusions Compared with arthroscopic rotator cuff repair alone, although the application of LP-PRP and LR-PRP could not reduce the rate of retear, it could significantly improve the shoulder joint function of patients, and LP-PRP could significantly reduce the pain of patients with rotator cuff injury in the early postoperative period (within 6 weeks), with no postoperative complications, and the short-term clinical results of patients were satisfactory. [ABSTRACT FROM AUTHOR]

Background: The impact of the etiology of rotator cuff injury (RCI) on outcomes after rotator cuff repair remains unclear. This study aimed to evaluate the postoperative outcomes of patients with RCIs of different etiologies and identify the risk factors affecting prognosis. Methods: This study included 73 patients with RCI who underwent arthroscopic rotator cuff repair. The patients were categorized into either a traumatic group or a non-traumatic group based on their history of trauma. Preoperative and postoperative assessments included shoulder range of motion, muscle strength, and physical examination findings specific to the shoulder for both groups. Clinical differences between arthroscopic repair of traumatic and non-traumatic RCIs were evaluated using univariate analysis. Logistic regression analysis determined independent risk factors for rotator cuff repair prognosis. Results: Among the 73 patients, 31 were in the traumatic group and 42 in the non-traumatic group, with a minimum postoperative follow-up of 12 months and a mean follow-up of 13.8 months. The duration of the disease was significantly longer in the non-traumatic group compared with the traumatic group (P < 0.001). The mean tear area was more significant in the traumatic group than in the non-traumatic group (P = 0.003), and the preoperative pain level and functional scores were better in the non-traumatic group compared with the traumatic group. Postoperatively, there were no differences between the two groups regarding scores, joint mobility, strength, and complications. At 12 months postoperatively, multivariate regression analysis indicated that full-layer tear (OR = 5.106, 95% CI: 1.137–22.927, P = 0.033), fat infiltration (OR = 6.020, 95% CI: 1.113–32.554, P = 0.037), and tear area (OR = 6.038, 95% CI: 2.122–17.177, P < 0.001) significantly affected the University of California at Los Angeles (UCLA) score. Conclusion: Compared with non-traumatic RCI, traumatic RCI presents with more pronounced pain and impaired joint function preoperatively yet demonstrates comparable postoperative clinical outcomes. Full-layer tears, fat infiltration, and large tear areas are unfavorable factors affecting rotator cuff repair, and postoperative rehabilitation management of these patients should be emphasized. [ABSTRACT FROM AUTHOR]

Background: Shoulder pain and disability from rotator cuff tears remain challenging clinical problem despite advancements in surgical techniques and materials. To advance our understanding of injury progression and develop effective therapeutics using tissue engineering and regenerative medicine approaches, it is crucial to develop and utilize animal models that closely resemble the anatomy and display the pathophysiology of the human rotator cuff. Among various animal models, the rabbit shoulder defect model is particularly favored due to its similarity to human rotator cuff pathology. However, a standardized protocol for creating a massive rotator cuff defect in the rabbits is not well defined. Therefore, the objective of our study was to establish a robust and reproducible model of a rotator cuff defect to evaluate the regenerative efficacy of scaffolds. Results: In our study, we successfully developed a rabbit model with a massive supraspinatus tendon defect that closely resembles the common rotator cuff injuries observed in humans. This defect involved a complete transection of the tendon, spanning 10 mm in length and encompassing its full thickness and width. To ensure stable scaffolding, we employed an innovative bridging suture technique that utilized a modified Mason-Allen suture as a structural support. Moreover, to assess the therapeutic effectiveness of the model, we utilized different scaffolds, including a bovine tendon extracellular matrix (ECM) scaffold and a commercial acellular dermal matrix (ADM) scaffold. Throughout the observation period, no scaffold damage was observed. Notably, comprehensive histological analysis demonstrated that the regenerative tissue in the tendon ECM scaffold group exhibited an organized and aligned fiber structure, indicating tendon-like tissue regeneration while the tissue in the ADM group showed comparatively less organization. Conclusions: This study presents a comprehensive description of the implemented procedures for the development of a highly reproducible animal model that induces massive segmental defects in rotator cuff tendons. This protocol can be universally implemented with alternative scaffolds to investigate extensive tendon defects and evaluate the efficacy of regenerative treatments. The application of our animal model offers a standardized and reproducible platform, enabling researchers to systematically evaluate, compare, and optimize scaffold designs. This approach holds significant importance in advancing the development of tissue engineering strategies for effectively repairing extensive tendon defects. [ABSTRACT FROM AUTHOR]

This paper presents a detailed gross description of all anatomical elements of the humerus in the African green monkey and provides comparative and differential elements on monkey osteology. The osteometric investigation adds value to the gross morphological investigation, adjoining metric data to the gross descriptive data set. An in-depth investigation of the microstructural aspects of the humeral bone tissue is provided, with qualitative and quantitative details and potential for diagnostic applications. Of the gross morphological elements described, several unique features specific to this species include the humeral head shape that presents with distinctive low convexity and caudal placement, the shape of the intertubercular groove, the less developed greater tubercle, and the disposition of the rotator cuff muscle insertion. Furthermore, the overall cranio-lateral curvature of the bone shaft was found to have a distinctive 154–155 degree of angulation of the diaphysis, and the well-developed medial epicondyle was observed with its distinctive medio-caudal retroflexion. The histological investigation was more indicative of a typical non-primate organization of the bone tissue, with laminar vascular and avascular structures combined with the presence of the secondary Haversian system involving a mixture of scattered and dense unorganized secondary osteonal structures. The histomorphometric investigation yielded metrical data for the secondary osteonal structures in terms of area (20,331 ± 5105 µm2), perimeter, and vascular canal area (64,769 ± 257 µm2). [ABSTRACT FROM AUTHOR]

Background: Reverse shoulder arthroplasty (RSA) is an established operative treatment for failed rotator cuff repair (RCR) that may not be amenable to revision repair. The purpose of this meta-analysis is to evaluate the clinical outcomes for patients undergoing RSA following prior failed RCR compared with patients without prior RCR undergoing primary RSA. Methods: A systematic search of articles in Pubmed, EMBASE and The Cochrane Library databases was carried out according to PRISMA guidelines. Comparative studies assessing outcomes of RSA after failed RCR versus primary RSA were included. Results: Seven studies with 2149 total patients were included; 760 patients had a prior RCR and 1389 patients did not have a prior RCR. Prior failed RCR resulted in significantly lower postoperative ASES scores (mean difference [MD], −8.31 95% confidence interval [CI] −10.96, −5.66), less forward flexion (MD, −6.71 95%CI −11.75, −1.67), and higher VAS pain scores (MD; 0.85, 95% CI 0.47, 1.22) when compared to primary RSA. There were no significant differences in external rotation, complications rate, or rate of revision. Conclusion: This study found that failed RCR prior to RSA was associated with lower functional outcomes scores, higher pain scores, and worse range of motion compared to primary RSA without prior RCR. [ABSTRACT FROM AUTHOR]

Objective: To identify the prevalence and type of rotator cuff injuries in Brazilian jiu-jitsu practitioners. Method: A cross-sectional and association evaluating patients through non-probabilistic, convenience sampling, performing a bilateral shoulder ultrasound. Results: In the present study, 40 patients practicing Brazilian jiu-jitsu were evaluated; 75% (n = 30) were male and 25% (n = 10) were female, in an age range of 19 to 53 years, with an average age of 31 years, a weight of 80.5 kg (BMI of 27), 82.5% (n = 33) reported pain or discomfort in any of the shoulder arcs of movement, with abduction being more common, with an overall prevalence of 70% (n = 28), followed by flexion (35%, n = 14), extension (22.5%, n = 9), internal rotation (17.5%, n = 7), rotation external (7.5%, n = 3) and adduction (7.5%, n = 3). Conclusions: Eighty percent presented ultrasound findings compatible with rotator cuff injury; the supraspinatus muscle tendon was the most affected element (72.5%). The most frequent finding was tendinopathy in 70% of the practitioners. [ABSTRACT FROM AUTHOR]

Introduction: The shoulder joint's stability is largely provided by the rotator cuff muscles and tendons, crucial for dynamic stabilization. Pathologies in these muscles are major causes of shoulder pain and disability. USG and MRI are non-invasive, radiation-free imaging methods with high sensitivity for diagnosing rotator cuff disorders, offering complementary diagnostic insights. Methodology: Patients presenting with complaints of pain in shoulder joint, restricted movements or clinical suspicion of RC disorders were referred to Radiodiagnosis Department of Muzaffarnagar Medical college. In this study, 30 patients of both genders were studied in age between 20 to 60 years. HRUSG followed by MRI of the affected side shoulder was performed. Result: In this study, 60% of males and 40% of females were affected, primarily in the 41-50 age group. The supraspinatus tendon was most commonly impacted, with MRI outperforming USG in detecting pathologies. USG showed high specificity and moderate sensitivity and accuracy in identifying rotator cuff tears, particularly full-thickness tears (FTT). However, USG was less effective in detecting infraspinatus and subscapularis tendon issues. Both imaging modalities have limitations, with USG unable to properly evaluate abnormalities of the glenoid labrum, various ligaments, and bones. Tears were associated with subacromial-subdeltoid and Sub coracoid bursitis. Conclusion: Clinical examination, X-ray, and CT scans offer limited insight into shoulder joint pathologies, particularly for soft tissues like the rotator cuff. HRUSG, being affordable, non-invasive, and real-time, is the first-line diagnostic tool for screening rotator cuff disorders. MRI serves as a problem-solving modality, offering detailed evaluation in complex cases involving glenoid labrum, ligaments, bones, and muscle atrophy, especially when USG results are inconclusive. [ABSTRACT FROM AUTHOR]

Purpose: Rotator cuff (RC) disorders are the most common cause of shoulder disability. The aim of this study was to quantify the evidence on the sex‐related differences in RC repair. Methods: A systematic review of the literature was performed in January 2023 in PubMed, Wiley Cochrane Library and Web of Science on research articles on humans with RC tears treated surgically. A meta‐analysis was performed to compare results in men and women. The Downs and Black score and the modified Coleman methodology score (MCMS) were used to assess the retrieved studies. Results: A total of 39,909 patients were enroled in the 401 studies analysed (45% women, 55% men). A trend toward more sex‐balanced recruitment was observed over time. Only 4% of the studies on 1.5% of the documented patients presented disaggregated outcome data and were quantitatively analysed. A tendency for lower range of motion values after surgery was found for external shoulder rotation in women, with 39.9° ± 6.9° versus 45.3° ± 4.1° in men (p = 0.066). According to Downs and Black scores, four studies were good and 12 fair, with a main MCMS score of 69/100. Conclusion: There is a lack of awareness on the importance to document women‐ and men‐specific data. Only 4% of the articles disaggregated data, and it was possible to analyse only 1.5% of the literature population, a sample which cannot be considered representative of all patients. The lack of disaggregated data is alarming and calls for action to better study men and women differences to optimise the management of RC tears. This will be necessary to provide sex‐specific information that could be of clinical relevance when managing RC repair. Level of Evidence: Level IV. [ABSTRACT FROM AUTHOR]

Background: Bone marrow stimulation (BMS) has been proposed to augment healing at the time of arthroscopic rotator cuff repair (ARCR) by creating several bone marrow vents in the footprint of the rotator cuff, allowing mesenchymal stem cells, platelets, and growth factors to cover the area as a "crimson duvet." Purpose: To perform a meta-analysis of randomized controlled trials (RCTs) to compare the outcomes after BMS and a control for those undergoing ARCR. Study Design: Meta-analysis; Level of evidence, 1. Methods: A literature search of 3 databases was performed based on the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. RCTs comparing BMS and a control for ARCR were included. Clinical outcomes were compared, and a P value <.05 was considered to be statistically significant. Results: A total of 7 RCTs with 576 patients were included. Overall, 18.8% of patients treated with BMS and 21.0% of patients treated with a control had a retear (I 2 = 43%; P =.61). With BMS, the mean Constant score was 88.2, and with the control, the mean Constant score was 86.7 (P =.12). Additionally, there was no significant difference in the American Shoulder and Elbow Surgeons score (94.3 vs 93.2, respectively; P =.31) or visual analog scale score (0.9 vs 0.9, respectively; P =.89). Conclusion: The level 1 evidence in the literature did not support BMS as a modality to improve retear rates or clinical outcomes after ARCR. [ABSTRACT FROM AUTHOR]

Full‐thickness rotator cuff tears can lead to poor coaptation of the humeral head to the glenoid, disrupting muscle forces required for glenohumeral joint stability, ultimately leading to joint subluxation. The aim of this study was to evaluate muscle forces and glenohumeral joint translations during elevation in the presence of isolated and combined full‐thickness rotator cuff tears. Eight fresh‐frozen upper limbs were mounted to a computer‐controlled testing apparatus that simulated joint motion by simulated muscle force application. Scapular‐plane abduction was performed, and glenohumeral joint translations were measured using an optoelectronic system. Testing was performed in the native shoulder, a following an isolated tear to the supraspinatus, as well as combined tears involving the supraspinatus and subscapularis, as well as supraspinatus, infraspinatus, and teres minor. Rotator cuff tears significantly increased middle deltoid force at 30°, 60°, and 90° of abduction relative to that in the native shoulder (p < 0.05). Significantly greater superior translations were observed relative to the intact shoulder due to combined tears to the supraspinatus and infraspinatus at 30° of abduction (mean increase: 1.6 mm, p = 0.020) and 60° of abduction (mean increase: 4.8 mm, p = 0.040). This study illustrates the infraspinatus‐teres minor complex as a major humeral head depressor and contributor to glenohumeral joint stability. An increase in deltoid force during abduction occurs in the presence of rotator cuff tears, which exacerbates superior migration of the humeral head. The findings may help in the development of clinical tests in rotator cuff tear diagnostics, in surgical planning of rotator cuff repair, and in planning of targeted rehabilitation. [ABSTRACT FROM AUTHOR]

Amibegron, a β3‐adrenergic receptor (B3AR) agonist, has recently been shown to provide therapeutic effects for chronic rotator cuff (RC) tears by inducing the expression of uncoupling protein 1 (UCP‐1), a marker of brown fat, in fibroadipogenic progenitors (FAPs). However, it remains to be seen if these beneficial effects hold true with age and in older, more clinically relevant populations. This study seeks to understand the impacts of aging on the efficacy of amibegron to treat chronic RC tears. Young (4‐month‐old) and aged (33‐month‐old) C57BL/6 mice underwent a RC injury procedure with delayed repair (DR). Mice were equally randomized to receive amibegron or dimethyl sulfoxide (DMSO) treatments after repair. Functional ability was measured at baseline and 6‐weeks after DR. Wet muscle weight and histology of injured and contralateral supraspinatus were also analyzed 6‐weeks post‐DR. For in vitro histology and real‐time quantitative PCR experiments, FAPs were isolated from young and aged mice via fluorescence‐activated cell sorting. Young and aged FAPs were treated with amibegron or DMSO either immediately after seeding (early exposure) or 8‐days after seeding (late exposure). In vitro results showed that amibegron‐mediated FAP UCP‐1 expression decreases with age. In vivo data demonstrated that aged mice have a decreased responsiveness to amibegron and decreased propensity for intramuscular FAP UCP‐1 expression. Further, delayed amibegron treatment with RC repair did not lead to improvements in muscle atrophy and functional outcomes. Our findings demonstrate that age and the timing of interventions play a critical role in FAP‐targeted therapeutics for chronic injuries. [ABSTRACT FROM AUTHOR]

As part of an investigation to detect asymmetries in gait patterns in persons with shoulder injuries, the goal of the present study was to design and validate a Kinect-based motion capture system that would enable the extraction of joint kinematics curves during gait and to compare them with the data obtained through a commercial motion capture system. The study included eight male and two female participants, all diagnosed with anterolateral shoulder pain syndrome in their right upper extremity with a minimum 18 months of disorder evolution. The participants had an average age of 31.8 ± 9.8 years, a height of 173 ± 18 cm, and a weight of 81 ± 15 kg. The gait kinematics were sampled simultaneously with the new system and the Clinical 3DMA system. Shoulder, elbow, hip, and knee kinematics were compared between systems for the pathological and non-pathological sides using repeated measures ANOVA and 1D statistical parametric mapping. For most variables, no significant difference was found between systems. Evidence of a significant difference between the newly developed system and the commercial system was found for knee flexion–extension (p < 0.004, between 60 and 80% of the gait cycle), and for shoulder abduction–adduction. The good concurrent validity of the new Kinect-based motion analysis system found in this study opens promising perspectives for clinical motion tracking using an affordable and simple system. [ABSTRACT FROM AUTHOR]

Background: To date, it is not well known which systemic pathologies most frequently afflict patients with rotator cuff tear (RCT) and whether the coexistence of two or more pathologies can affect the lesion size. Therefore, we analyzed our database relative to a large group of patients who recently underwent rotator cuff repair. Methods: A total of 527 patients with full-thickness RCT were enrolled. For each patient, we checked the presence of at least one of diabetes, venous system diseases, cardiovascular diseases, hypercholesterolemia, blood hypertension, thyroid diseases, and a smoking habit. Patients were subdivided according to risk factors into five groups, representing those who had zero, one, two, three, and four or more risk factors, respectively. Statistical analysis was performed. Results: In total, 37% of our patients had no risk factors; 28% had one risk factor (arterial hypertension, smoking habit, and hypercholesterolemia were the most frequent); 23% had two risk factors (the hypertension/hypercholesterolemia association was the most frequent); and 8% suffered from three pathologies (the diabetes/arterial hypertension/hypercholesterolemia association was the most frequent). Comparing the cuff tear severity in patients without and with at least one risk factor, we observed that tear size increased in those with at least one risk factor. Conclusions: A total of 63% of patients with rotator cuff tears were either smokers and/or had at least one pathology capable of altering the peripheral microcirculation. Hypertension and hypercholesterolemia were the most frequent. Tear severity significantly increased with the presence of at least one risk factor. [ABSTRACT FROM AUTHOR]

In the field of sports medicine, repair surgery for anterior cruciate ligament (ACL) and rotator cuff (RC) injuries are remarkably common. Despite the availability of relatively effective treatment modalities, outcomes often fall short of expectations. This comprehensive review aims to thoroughly examine current strategies employed to promote tendon‐bone healing and analyze pertinent preclinical and clinical research. Amidst ongoing investigations, tendon‐derived stem cells (TDSCs), which have comparatively limited prior exploration, have garnered increasing attention in the context of tendon‐bone healing, emerging as a promising cell type for regenerative therapies. This review article delves into the potential of combining TDSCs with tissue engineering methods, with ACL reconstruction as the main focus. It comprehensively reviews relevant research on ACL and RC healing to address the issues of graft healing and bone tunnel integration. To optimize tendon‐bone healing outcomes, our emphasis lies in not only reconstructing the original microstructure of the tendon‐bone interface but also achieving proper bone tunnel integration, encompassing both cartilage and bone formation. In this endeavor, we thoroughly analyze the transcriptional and molecular regulatory variables governing TDSCs differentiation, incorporating a retrospective analysis utilizing single‐cell sequencing, with the aim of unearthing relevant signaling pathways and processes. By presenting a novel strategy rooted in TDSCs‐driven osteogenic and chondrogenic differentiation for tendon‐bone healing, this study paves the way for potential future research avenues and promising therapeutic applications. It is anticipated that the findings herein will contribute to advancing the field of tendon‐bone healing and foster the exploration of TDSCs as a viable option for regenerative therapies in the future. [ABSTRACT FROM AUTHOR]

Purpose: Rotator cuff related shoulder pain is common among older adults. While exercise is often recommended for this condition, the relationship between physical activity levels and self-reported outcomes is unclear. This study investigated whether self-reported outcomes (pain, function, depressive symptoms, self-efficacy, general mental and physical health) relate to physical activity, and whether those who participated in shoulder-specific exercise had better self-reported outcomes than those who performed whole-body exercise. Methods: Forty-six participants with rotator cuff related shoulder pain participated from which 35 had complete datasets. Questionnaires were used to assess physical activity, pain, physical function, general health, and self-efficacy. Physical activity levels were also measured using an accelerometer. Results: Neither pain nor other self-reported outcomes were related to subjective or objective physical activity levels. Participants that completed shoulder-specific exercise had significantly higher exercise self-efficacy than those who completed nonspecific exercise (P =.01; d = 0.91). Conclusion: A significant relationship between pain or self-reported outcomes and physical activity was not identified. Those who self-reported regularly exercising their injured shoulder had higher exercise self-efficacy than those who did not. These findings have clinical implications, suggesting that strategies to boost exercise self-efficacy may be important for older adults with rotator cuff related shoulder pain. [ABSTRACT FROM AUTHOR]

Background: Abnormal posture is known to affect the efficacy of exercise therapy for musculoskeletal diseases. However, no studies to date have examined the effect of exercise programs should take into account the posture of the upper body in patients with rotator cuff disease. This study aimed to assess how rotator cuff and corrective exercises impact shoulder function and muscle strength post-arthroscopic rotator cuff repair surgery, providing tailored rehabilitation programs for patients with forward posture. Methods: Ninety male patients who underwent arthroscopic rotator cuff repair participated in this study. The patients were randomly divided into three groups corrective exercise group (CEG, n = 29), rotator cuff exercise group (REG, n = 27), and control group (CG, n = 28). Each group was instructed to apply different exercise programs to correct posture and enhance rotator cuff strength. All patients were checked by the American Shoulder and Elbow Surgeons (ASES) score, Constant score and muscle strength, and range of motion preoperatively and postoperatively at 6 months and 1 year. Results: ASES shoulder function scores showed significant difference between the three groups (p = 0.002, F = 7.03), indicating that the corrective exercise program was more beneficial than rotator cuff exercises (p = 0.009, F = 3.78). A significant intergroup difference in mean Constant score was also noted (p = 0.025, F = 3.86), while a statistically significant interaction between time and group was observed (p = 0.032, F = 2.96). Conclusions: These results suggested that a corrective exercise program can improve shoulder muscle strength and function after rotator cuff repair in male patients with a forward shoulder posture. [ABSTRACT FROM AUTHOR]

Rotator cuff tendinopathy is a common musculoskeletal disorder with limited pharmacological treatment strategies. This study aimed to investigate tenocytes’ functional in vitro response from a ruptured supraspinatus tendon to suramin administration and to elucidate whether suramin can enhance tendon repair and modulate the inflammatory response to injury. Tenocytes were obtained from human supraspinatus tendons (n = 6). We investigated the effect of suramin on LPS‐induced inflammatory responses and the underlying molecular mechanisms in THP‐1 macrophages. Suramin enhanced the proliferation, cell viability, and migration of tenocytes. It also increased the protein expression of PCNA and Ki‐67. Suramin‐treated tenocytes exhibited increased expression of COL1A1, COL3A1, TNC, SCX, and VEGF. Suramin significantly reduced LPS‐induced iNOS, COX2 synthesis, inflammatory cytokine TNF‐α production, and inflammatory signaling by influencing the NF‐κB pathways in THP‐1 cells. Our results suggest that suramin holds great promise as a therapeutic option for treating rotator cuff tendinopathy. [ABSTRACT FROM AUTHOR]

In people with shoulder pain, what is the effect of adding mobilisation with movement (MWM) to a standard exercise program on function and pain compared with sham MWM and the same exercise program? A randomised trial with concealed allocation, blinded outcome assessment and intention-to-treat analysis. Seventy people with chronic atraumatic rotator cuff related pain, with a mean age 48 years (SD 10). The experimental group received MWM plus exercise and the control group received sham MWM plus exercise. Treatments were delivered twice per week for 5 weeks. The primary outcome measures were function (0 to 100 Shoulder Pain and Disability Index) and pain (0 to 10 Numerical Pain Rating Scale). Secondary outcomes were self-efficacy, perceived improvement and active pain-free range of movement. Assessment time points were at baseline (week 0), the end of the treatment period (week 5) and a follow-up 1 month after the end of treatment (week 9). At week 5, the experimental group improved more than the control group in function (MD –15 points, 95% CI –24 to –7), pain at night (MD –2.1, 95% CI –3.1 to –1.1), pain on movement (MD –1.5, 95% CI –2.5 to –0.6) and active range of movement in flexion (MD 16 deg, 95% CI 1 to 30), abduction (MD 23 deg, 95% CI 6 to 40), external rotation (MD 11 deg, 95% CI 4 to 17) and hand behind back (MD 20 deg, 95% CI 8 to 32). At week 9, benefits were seen in the Shoulder Pain and Disability Index (MD –9 points, 95% CI –17 to –1), pain at night (MD –1.9, 95% CI –2.9 to –0.8) and on movement (MD –1.3, 95% CI–2.3 to –0.3). The effects of the experimental intervention on other outcomes were mostly unclear due to wide confidence intervals. Blinding was successful. Adding MWM to exercise improved function, pain and active range of movement in people with shoulder pain. These benefits were not placebo effects. NCT04175184. [ABSTRACT FROM AUTHOR]

Background: Restoring shoulder strength after arthroscopic rotator cuff repair (ARCR) is critical, but there is limited understanding as to what patients consider satisfactory postoperative strength. Purpose: To determine the Patient Acceptable Symptom State (PASS) values for the Constant score strength parameter and internal rotation (IR) strength in patients who underwent ARCR for rotator cuff tears involving the subscapularis (SSC) muscle and evaluate for associations between preoperative and intraoperative patient characteristics with PASS achievement. Study Design: Case-control study; Level of evidence, 3. Methods: A retrospective analysis was conducted on prospectively collected data for 278 patients with an SSC tear (isolated or combined) who underwent ARCR and had minimum 2-year follow-up data. Functional outcomes (patient-reported outcomes, range of motion, Constant strength, and IR strength) were assessed preoperatively and at the latest follow-up. The overall, male, and female PASS values for postoperative strength measures were evaluated using receiver operating characteristic analysis. Correlation and logistic regression analyses were used to evaluate the relationship between preoperative variables and PASS achievement for Constant and IR strengths. Results: The mean follow-up time was 72.8 months. The overall, male, and female PASS values were 9.9 lb (4.5 kg), 14.5 lb (6.6 kg), and 8.5 lb (3.9 kg), respectively, for Constant strength and 15.2 lb (6.9 kg), 20.7 lb (9.4 kg), and 12.1 lb (5.5 kg), respectively, for IR strength. Older age, high fatty infiltration of the SSC tendon (Goutallier grades 3 and 4), and failure of SSC healing correlated negatively with PASS attainment for the strength measures. High fatty infiltration of the supraspinatus and infraspinatus muscles correlated negatively with Constant strength. Decreased coracohumeral distance (CHD) and larger SSC tears correlated negatively with achieving PASS for IR strength. Workers' compensation, high supraspinatus and SSC fatty infiltration, and the use of knotted suture anchors were predictors of not achieving the overall Constant strength PASS, while lower SSC fatty infiltration and high CHD were predictors of achieving the overall IR strength PASS. Conclusion: This study established the PASS values for Constant and IR strengths for patients after ARCR involving the SSC tendon. Workers' compensation, high supraspinatus and SSC fatty infiltration, and the use of knotted suture anchors were predictors of not achieving the overall Constant strength PASS, while lower SSC fatty infiltration and high CHD were predictors of achieving the overall IR strength PASS. [ABSTRACT FROM AUTHOR]

Background: The addition of epinephrine to arthroscopic irrigation fluid has been shown to improve surgeon-rated visual clarity during shoulder arthroscopic surgery. Subacromial injections of epinephrine are also used for this purpose. Purpose/Hypothesis: To assess the influence of a preoperative subacromial epinephrine injection on surgeon visualization during subacromial shoulder arthroscopic surgery. It was hypothesized that the epinephrine injection would improve surgeon-rated visual clarity. Study Design: Randomized controlled trial; Level of evidence, 1. Methods: A double-blind randomized controlled trial including adult patients undergoing shoulder arthroscopic surgery in the beach-chair position requiring visualization of the subacromial space was performed. Patients in the epinephrine group (n = 30) received a preoperative subacromial injection of bupivacaine and epinephrine, and those in the control group (n = 30) received a preoperative subacromial injection of bupivacaine. Epinephrine was added to the first 10 L of arthroscopic irrigation fluid in all patients. The primary outcome was surgeon-rated visual clarity throughout the procedure that was recorded at the end of the procedure using a visual analog scale (VAS) scored from 0 (worst) to 10 (best). Secondary outcomes included an increase in pump pressure during the procedure, total operative time, and the intraoperative use of blood pressure–modulating medications. Results: Rotator cuff repair was performed in 88.3% of patients (25/30 epinephrine; 28/30 control), with multiple procedures performed in 85.0% of patients (23/30 epinephrine; 27/30 control). The VAS score for visual clarity was slightly better in the epinephrine group compared with the control group, although the difference was neither statistically nor clinically significant (8.3 ± 1.4 vs 7.5 ± 1.8, respectively; P =.09). There was no difference between the epinephrine and control groups in the need for an increase in pump pressure to improve visualization (8/30 [26.7%] vs 7/30 [23.3%], respectively; P >.99), total operative time (62.0 ± 19.4 vs 64.0 ± 30.1 minutes, respectively; P =.90), or the intraoperative use of blood pressure–modulating medications (20/30 [66.7%] vs 17/30 [56.7%], respectively; P =.60). There were no perioperative adverse events in either group. Conclusion: The addition of a subacromial epinephrine injection before shoulder arthroscopic surgery resulted in a small improvement in visual clarity that was neither statistically nor clinically significant, with no adverse effects reported in this study. Registration: NCT05244525 (ClinicalTrials.gov) [ABSTRACT FROM AUTHOR]

Background: Excessively high repair tension, especially tension ≥10 N, can lead to unsuccessful rotator cuff repair. Purpose/Hypothesis: The purpose of this study was to identify the preoperative risk factors for high repair tension in rotator cuff repair. It was hypothesized was that older age, longer symptom duration, nontraumatic (ie, degenerative) tear onset, progressive fatty degeneration, and larger tear size would be among the risk factors. Study Design: Cross-sectional study; Level of evidence, 3. Methods: This retrospective study involved 80 patients (80 shoulders) diagnosed with rotator cuff tears by magnetic resonance imaging between July 2018 and August 2020. Repair tension was measured intraoperatively using a digital tension meter. Risk factors for high repair tension (≥10 N) were evaluated. The t test was used to assess the relationship of repair tension with patient characteristics and surgical parameters. Parameters with a P value of <.05 in the univariate analysis were entered into a multivariate logistic regression model to determine their relationship with repair tension ≥10 N. Results: Symptom duration of ≥4 months, nontraumatic tear onset, large/massive tears, mediolateral (ML) tear length of ≥20 mm, and anteroposterior (AP) tear length of ≥18 mm were associated with high odds of repair tension ≥10 N (P ≤.013 for all). Multivariate analysis showed that nontraumatic onset, ML tear length of ≥20 mm, and AP tear length of ≥18 mm were independent risk factors for repair tension ≥10 N (P ≤.035 for all). Conclusion: The independent risk factors for high repair tension (≥10 N) during rotator cuff repair were nontraumatic tear onset, ML tear length of ≥20 mm, and AP tear length of ≥18 mm. Symptom duration of ≥4 months and large/massive tears were associated with high odds of repair tension ≥10 N, although they were not considered independent risk factors. Prospective cohort studies with larger sample sizes are needed to confirm the clinical value of the risk factors identified in this study. [ABSTRACT FROM AUTHOR]