Infraspinatus Tendon Research Articles

Evaluation of the acromion variants in MRI and their association with rotator cuff injuries in non-traumatic patients

PurposeUnderstanding demographic and MRI parameters with determinant role in rotator cuff tearing (RCT) is required to predict outcomes and select more appropriate treatment in patients with non-traumatic shoulder pain. This study aimed to survey the association of rotator cuff tears with these factors. MethodsWe performed this cross-sectional study on patients referred to Kashani Hospital with non-traumatic shoulder pain suspected of rotator cuff injuries from April 2020 to February 2021. We obtained their demographic data and MRI from electronic hospital records. After that, two radiologists reviewed MRI and recorded data. We employed the SPSS 23 software to organize the obtained results and statistical evaluations. Results371 subjects, with the age of 48.61 ± 14.89 years, were included in our study, and 50% of them were male. The flat and down-sloping acromion and partial tearing of the supra and infraspinatus tendons were more frequent than the others. Gender could not consider as a determinant factor for the severity of tendon injuries, acromion types and variants. The relation of age to acromion morphology and the tendinopathy severity was significant. Remarkably, down-sloping acromion was higher at all the acromion shapes; however, it makes no difference in the level of supra and infraspinatus involvement. Moreover, we found that partial tearing was higher in all acromion types, except concave. This distribution was significant only for supraspinatus tears. ConclusionThe clinical decision is the most important step in patients with RCT and MRI prognostic factors, which are helpful to improve the management of the cases. RCT in older patients and down-slope acromion was more severe than the others. According to the previous studies, acromion morphology (as an important determinant factor) in RCT could be influenced by age, as well.

Case Study: Successful Rehabilitation of a Torn Rotator Cuff through Physical Therapy for Positive Functional Recovery

Older adults often suffer from shoulder pain. Rotator cuff problems are typically responsible for shoulder pain. The majority of rotator cuff disorders can be treated conservatively. Shoulder issues are rather common. More than 30% of people have shoulder pain at some time in their lives. Shoulder discomfort is one of the most frequent musculoskeletal problems in people over the age of 65. The rotator cuffs are four muscles that connect the top arm bone (humerus) to the upper shoulder blade (scapula). If the rotator cuff is injured, every motion on the affected shoulder, including flexion, extension, abduction, adduction, and internal and external rotation, may be difficult. Having a rotator cuff tear restricts movement of the shoulder, which makes it difficult for the patient to do everyday tasks such as getting dressed or washing their hair. They may also find it difficult to remove something from their back pockets. patient was completely immobile when injured. Treatment was provided for up to three months, and almost 30 rehabilitation sessions were conducted during this time. In each rehabilitation session, patients were treated with electrotherapeutic modalities, dry cupping, and manual therapy exercises. The rehabilitation session lasted up to an hour. After one month of rehabilitation, the shoulder pain was noticeably reduced and nearly gone. Following the treatment, she achieved the most improvement in her functional capacity. For instance, she is now able to put on clothes without any assistance. Now she can comb her hair on her own. It was proven that exercise treatment significantly reduced pain and improved function in individuals with fully ruptured or torn supraspinatus and infraspinatus tendons. Keywords: Rotator cuff, full thickness tear, disability, surgery, shoulder pain, physical therapy.

MICRO-FRAGMENTED ADIPOSE TISSUE IN THE SUCCESSFUL TREATMENT OF RECURRENT ROTATOR CUFF TEARS IN AN INJURED WORKER

This is the case of a 42-year-old right-handed male truck cargo mechanic who suffered a rotator cuff (RTC) tear of his right shoulder after a slip and fall while at work. An MRI of the shoulder demonstrated supra-spinatus and infraspinatus tendon tears. After a trial of 4 months of nonoperative treatment, he underwent arthroscopic repair of his RTC. Postoperatively, he completed a course of physical therapy (PT) and a work conditioning program. Unfortunately, he had ongoing pain, limitations in range of motion (ROM), and functional limitations, which prevented him from returning to work. A repeat MRI demonstrated a retear of supraspinatus and infraspinatus tendons. After consulting with the author, he underwent a micro-fragmented adipose tissue injection under ultrasound guidance into the involved tendons. After 4 weeks of additional PT, he was noted to have full, pain-free ROM with normal strength and was able to return to his full work duties, including overhead lifting without restrictions.

Rotator cuff repair with an interposition polypropylene mesh: A biomechanical ovine study.

Chronic large to massive rotator cuff tears are difficult to treat and re-tears are common even after surgical repair. We propose using a synthetic polypropylene mesh to increase the tensile strength of rotator cuff repairs. We hypothesize that using a polypropylene mesh to bridge the repair of large rotator cuff tears will increase the ultimate failure load of the repair. To investigate the mechanical properties of rotator cuff tears repaired with a polypropylene interposition graft in an ovine ex-vivo model. A 20 mm length of infraspinatus tendon was resected from fifteen fresh sheep shoulders to simulate a large tear. We used a polypropylene mesh as an interposition graft between the ends of the tendon for repair. In seven specimens, the mesh was secured to remnant tendon by continuous stitching while mattress stitches were used for eight specimens. Five specimens with an intact tendon were tested. The specimens underwent cyclic loading to determine the ultimate failure load and gap formation. The mean gap formation after 3000 cycles was 1.67 mm in the continuous group, and 4.16 mm in the mattress group (P = 0.001). The mean ultimate failure load was significantly higher at 549.2 N in the continuous group, 426.4 N in the mattress group and 370 N in the intact group (P = 0.003). The use of a polypropylene mesh is biomechanically suitable as an interposition graft for large irreparable rotator cuff tears.

The Effect of Pulling Angle on Rotator Cuff Mechanical Properties in a Canine In Vitro Model.

The objective of this study was to examine the effect of pulling angle on time-zero mechanical properties of intact infraspinatus tendon or infraspinatus tendon repaired with the modified Mason-Allen technique in a canine model in vitro. Thirty-six canine shoulder samples were used. Twenty intact samples were randomly allocated into functional pull (135°) and anatomic pull (70°) groups (n = 10 per group). The remaining sixteen infraspinatus tendons were transected from the insertion and repaired using the modified Mason-Allen technique before being randomly allocated into functional pull or anatomic pull groups (n = 8 per group). Load to failure testing was performed on all specimens. The ultimate failure load and ultimate stress of the functional pulled intact tendons were significantly lower compared with anatomic pulled tendons (1310.2 ± 167.6 N vs. 1687.4 ± 228.2 N, p = 0.0005: 55.6 ± 8.4 MPa vs. 67.1 ± 13.3 MPa, p = 0.0334). For the tendons repaired with the modified Mason-Allen technique, no significant differences were observed in ultimate failure load, ultimate stress or stiffness between functional pull and anatomic pull groups. The variance of pulling angle had a significant influence on the biomechanical properties of the rotator cuff tendon in a canine shoulder model in vitro. Load to failure of the intact infraspinatus tendon was lower at the functional pulling position compared to the anatomic pulling position. This result indicates that uneven load distribution across tendon fibers under functional pull may predispose the tendon to tear. However, this mechanical character is not presented after rotator cuff repair using the modified Mason-Allen technique.

Global Compressive Loading from an Ultra-Thin PEEK Button Augment Enhances Fibrocartilage Regeneration of Rotator Cuff Enthesis.

A PEEK button is developed to improve the tendon-to-bone compression area. In total, 18 goats were divided into 12-week, 4-week, and 0-week groups. All underwent bilateral detachment of the infraspinatus tendon. In the 12-week group, 6 were fixed with a 0.8-1 mm-thick PEEK augment (A-12, Augmented), and 6 were fixed with the double-row technique (DR-12). Overall, 6 infraspinatus were fixed with PEEK augment (A-4) and without PEEK augment (DR-4) in the 4-week group. The same condition was performed in the 0-week groups (A-0 and DR-0). Mechanical testing, immunohistochemistry assessment, cell responses, tissue alternation, surgical impact, remodeling, and the expression of type I, II, and III collagen of the native tendon-to-bone insertion and new footprint areas were evaluated. The average maximum load in the A-12 group (393.75 (84.40) N) was significantly larger than in the TOE-12 group (229.17 (43.94) N) (p < 0.001). Cell responses and tissue alternations in the 4-week group were slight. The new footprint area of the A-4 group had better fibrocartilage maturation and more type III collagen expression than in DR-4 group. This result proved the novel device is safe and provides superior load-displacement to the double-row technique. There is a trend toward better fibrocartilage maturation and more collagen III secretions in the PEEK augmentation group.

Partial infraspinatus tear with bursitis following an mRNA vaccination: a case report.

A 52-year-old Thai female without preexisting shoulder pathology and symptom had developed left shoulder pain for 3 days. Two weeks prior to shoulder pain, she received an mRNA COVID-19 vaccination. She positioned her arm in combined internal rotation with 60° of arm abduction. Her symptoms were pain in all directions of shoulder motion and tenderness at the bicipital groove and over the deltoid area. The testing of the rotator cuff power of the infraspinatus tendon showed pain. An MRI showed infraspinatus tendinosis with a low-grade (almost 50%) bursal-surface tear at the footprint of the superior fiber with associated overlying subacromial-subdeltoid bursitis. She was treated with both intraarticular and subacromial corticosteroid injections (triamcinolone acetate (40mg/ml) 1ml+1% lidocaine with adrenaline 9ml). She did not respond to oral naproxen but responded well to intraarticular and subacromial corticosteroid injections. The best way to deal with SIRVA is to prevent this condition by using the correct injection technique. First, the injection site should be two or three fingerbreadths below the mid-acromion process. Second, the needle's direction should be perpendicular to the skin. Third, using the correct needle penetration depth.

The AIUM Practice Parameter for the Performance of the Musculoskeletal Ultrasound Examination.

The AIUM Practice Parameter for the Performance of the Musculoskeletal Ultrasound Examination.

The Effect of Vitamin C and N-Acetylcysteine on Tendon-to-Bone Healing in a Rodent Model of Rotator Cuff Repair

Background: Oxidative stress inhibits tendon-to-bone healing after rotator cuff repair. Regulation of oxidative stress has the potential to accelerate this healing, but its mechanism remains unclear. Purpose: To investigate the effects of reducing oxidative stress by applying antioxidants, such as N-acetylcysteine (NAC) and vitamin C (VC), on rotator cuff repair in a rat rotator cuff repair model. Study design: Controlled laboratory study. Methods: A total of 48 Sprague Dawley rats underwent bilateral surgery to repair the infraspinatus tendon to its insertion site 1 week after detachment. Rats were assigned to either the NAC group, the VC group, or a control group. Histological evaluation was performed via hematoxylin-eosin or toluidine blue staining, and oxidative stress was assessed via dihydroethidium intensity and protein carbonyl concentration at 3 and 6 weeks. Superoxide dismutase 1 (SOD1), SOD2, SOD3, peroxiredoxin 5, collagen type I (COL1), COL3, matrix metalloproteinase 1 (MMP-1), MMP-3, and MMP-13 expression and SOD activity were determined at 3 and 6 weeks. Biomechanical tests were performed at 6 and 12 weeks. Results: Histological evaluation showed that the number of chondrocytes in the NAC group at 6 weeks and in the VC group at 3 and 6 weeks, the area of fibrocartilage at 6 weeks in the VC group, and collagen fibers at 6 weeks in the NAC and VC groups were significantly increased compared with those in the control group. Dihydroethidium intensity at 3 and 6 weeks and protein carbonyls at 6 weeks in the NAC and VC groups were significantly decreased. SOD1 expression and SOD activity at 3 weeks in the VC group and peroxiredoxin 5 expression at 6 weeks in the NAC group were significantly upregulated compared with that in the control group. COL3 expression was significantly upregulated at 6 weeks in the VC group, and MMP-13 expression was significantly decreased at 6 weeks in the NAC and VC groups. The biomechanical strength showed no significant difference. Conclusion: Antioxidant treatment, via NAC or VC administration, reduced oxidative stress in the rotator cuff repair site and accelerated healing. Clinical Relevance: These findings provide essential indications to develop clinical strategies for improved healing after rotator cuff surgical repair in patients.

THE USE OF AN INTERPOSITION POLYPROPYLENE MESH IN ROTATOR CUFF REPAIR: A BIOMECHANICAL STUDY

This study aims to investigate the mechanical properties of a rotator cuff tear repaired with a polypropylene interposition graft in an ovine infraspinatus ex-vivo model.Twenty fresh shoulders from skeletally mature sheep were used in this study. A tear size of 20 mm from the tendon joint was created in the infraspinatus tendon to simulate a large tear in fifteen specimens. This was repaired with a polypropylene mesh used as an interposition graft between the ends of the tendon. Eight specimens were secured with mattress stitches while seven were secured to the remnant tendon on the greater tuberosity side by continuous stitching. Remaining five specimens with an intact tendon served as a control group. All specimens underwent cyclic loading with a universal testing machine to determine the ultimate failure load and gap distance.Gap distance increased with progressive cyclic loading through 3000 cycles for all repaired specimens. Mean gap distance after 3000 cycles for both continuous and mattress groups are 1.7 mm and 4.2 mm respectively (P = .001). Significantly higher mean ultimate failure load was also observed with 549.2 N in the continuous group, 426.6 N in the mattress group and 370 N in the intact group.The use of a polypropylene mesh as an interposition graft for large irreparable rotator cuff tears is biomechanically suitable and results in a robust repair that is comparable to an intact rotator cuff tendon. When paired with a continuous suturing technique, it demonstrates significantly resultant superior biomechanical properties that may potentially reduce re-tear rates after repairing large or massive rotator cuff tears.

Accuracy of Shoulder Ultrasound for Diagnosis of Rotator Cuff Pathologies

To assess accuracy of shoulder ultrasound (USG) for diagnosis of rotator cuff pathologies. Seventy- four adult patients in age range of 30-80 years with rotator cuff pathologies of either gender were subjected to USG taken with Philips IU22 and a 5-12 MHz linear array transducer. All tendons were examined and grayscale 2D USG images were stored. Sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) was measured. USG findings showed intact supraspinatus tendons in 36 and 32, full tear in 8 and 10, partial tear in 2 and 7 and tendinosis in 28 and 25 cases respectively. Statistical analysis showed non- significant difference (P&gt;0.05). USG findings showed intact infraraspinatus tendons in 45 and 41, full tear in 0 and 7, partial tear in 3 and 10 and tendinosis in 26 and 16 cases respectively. Statistical analysis showed significant difference (P&lt;0.05). USG findings showed intact biceps tendons in 50 and 48, full tear in 2 and 3, partial tear in 4 and 4 and tendinosis in 18 and 19 cases respectively. Statistical analysis showed non- significant difference (P&gt;0.05). A high accuracy, sensitivity, specificity, PPV and NPV was observed with USG in diagnosis of supraspinatus tendon, infraspinatus tendon, biceps tendons, subcapularis tendons. USG found to be effective in assessment of rotator cuff pathologies having high sensitivity, specificity, positive predictive and negative predictive values.

Delamination of rotator cuff tears: Real-time dynamic ultrasound findings.

The purpose of this study was to evaluate the value of diagnosing delaminated tears and ultrasonic characteristics on real-time dynamic ultrasound. We enrolled 143 consecutive patients who underwent arthroscopic rotator cuff repair between April 2020 and January 2021. All patients were examined using real-time dynamic ultrasound of the shoulder within 2 weeks before arthroscopy. In our study, delaminated tears were defined as intratendinous horizontal splitting with or without the retraction of the articular or bursal layer of tendon. Delaminated tears were classified into three types on the basis of their shape: greater retraction of the articular layer (type I), greater retraction of the bursal layer (type II), and equal retraction of both layers (type III). The sensitivity and specificity of real-time dynamic ultrasound for evaluation of delaminated tears were calculated using arthroscopy findings as the gold standard. Ultrasonic imaging appearances of delaminated rotator cuff tears were further described. Of the 143 patients, 47 (32.9%) had delaminated tears as confirmed by arthroscopy; 35 of these tears involved the supraspinatus tendon and 12 involved both supraspinatus and infraspinatus tendons. Real-time dynamic ultrasound correctly diagnosed 36 of 47 delaminated tears with sensitivity 72.0% (57.2%-83.3%) and specificity 96.7% (90.2%-99.2%). Moreover, type I tear (n = 32) was more common than type II (n = 11) and type III tears (n = 4). Real-time dynamic ultrasound evaluated shape of type I, type II, and type III with a sensitivity and specificity of 56% and 80%, 72% and 83%, and 100% and 98%, respectively. Anechoic horizontal linear splitting of tendon, unequal retraction of the bursal and articular layers, and thinning of the suffering tendon were the three signs observed during real-time dynamic ultrasound examination. These three signs were indicative of a diagnosis of delaminated rotator cuff tears with high specificities (100.0%, 100.0%, and 97.9%, respectively) but relatively low sensitivities (25.5%, 25.5%, and 36.2%, respectively). Real-time dynamic ultrasound can be practically used for diagnosing delamination of rotator cuff tears with medium sensitivity and high specificity. Anechoic horizontal linear splitting of tendon, unequal retraction of the bursal and articular layers, and thinning of the involved tendon are the three important ultrasonic signs for diagnosis of delaminated rotator cuff tears.

Biphasic Interpositional Allograft for Rotator Cuff Repair Augmentation Is Safe in an Ovine Model

This study is a preclinical histological assessment of a biphasic acellular interpositional cancellous allograft in an ovine model of rotator cuff repair (RCR) designed to better understand its safety profile and effects on tendon healing after rotator cuff repair. Thirty skeletally mature sheep with clinically normal shoulders with an artificially created degenerative infraspinatus tendon (IST) tear were randomized to control and treatment groups. Animals were euthanized at 3-weeks, 6-weeks, and 12-weeks. After gross dissection, rotator cuff specimens were fixed with formalin and polymerized for sectioning and staining. Blinded histological scores evaluated inflammatory cell infiltrates, signs of degradation, particulate debris, collagen arrangement, neo-vascularization, and enthesis qualitative measures. There were no treatment specimens that exhibited histological signs of a significant infection, inflammatory infiltrate, or foreign body reaction such as granuloma or fibrous capsule formation. Histological scores in all categories were not significantly different at all time points, including the primary endpoint mean cumulative inflammatory score (control: 3.66 ± 1.21 versus treated: 4.33 ± 1.51, p = 0.42), when comparing the treatment and control RCR groups. In general, the degree of tendon healing and host tissue response was essentially equivalent between the two groups with observation of low overall levels of inflammation and progressive improvements in collagen organization, reduced tenocyte activity, and fibrocartilaginous enthesis reformation. This histological study demonstrated the use of a biphasic interpositional allograft for rotator cuff repair augmentation in an ovine model does not generate an inflammatory response or foreign body reaction. Use of the biphasic interpositional allograft resulted in a histological profile that was essentially equivalent to that of a standard RCR at 3-, 6-, and 12-week post-operative timepoints. These findings suggest that a biphasic interpositional allograft is safe for further clinical investigation in humans before broader clinical application. Patch augmentation of RCR is a popular technique that has shown clinical success in improving the likelihood of a successful repair in patients at elevated risk for retear. Newer augmentation technologies are being developed to address the biology at the interface between the bone and soft tissue where failure typically occurs.

Translated article] Correlation between the incidence of rotator cuff lesion in traumatic unilateral anterior glenohumeral dislocation and the contralateral shoulder

IntroductionAnterior glenohumeral dislocation in patients older than 60 years is related to rotator cuff lesion because of its pre-existing degenerative condition. However, in this age group, the scientific evidence fails to elucidate whether rotator cuff lesions are the cause or consequence of recurrent shoulder instability. The objective of this paper is to describe the prevalence of rotator cuff injuries in a series of consecutive shoulders in patients older than 60 years who suffered a first episode of traumatic glenohumeral dislocation, and its correlation with rotator cuff injuries in both shoulders. MethodsRetrospectively, 35 patients over 60 years of age who had a first episode of unilateral traumatic anterior glenohumeral dislocation and who had MRI of both shoulders were studied, evaluating both shoulders with MRI to determine the structural damage correlation of the rotator cuff and long head of the biceps between them. ResultsWhen assessing the existence of partial or complete injury to the supraspinatus and infraspinatus tendons, the concordance on the affected and healthy sides, we have shown concordant results on both sides in 88.6 and 85.7%, respectively. The Kappa concordance coefficient was 0.72 for supraspinatus and infraspinatus tendons tear. Of the total of 35 cases evaluated, 8 (22.8%) presented at least some alteration in the tendon of the long head of the biceps on the affected side and only one (2.9%) on the healthy side, where the Kappa coefficient of concordance was 0.18. Of the 35 cases evaluated, 9 (25.7%) presented at least some retraction in the tendon of the subscapularis muscle on the affected side, while no participant showed signs of retraction in the tendon of this muscle on the healthy side. ConclusionsOur study has found a high correlation of the presence of a postero-superior rotator cuff injury after presenting a glenohumeral dislocation between the shoulder that has suffered the event and the presumably healthy contralateral shoulder. Nevertheless, we have not found this same correlation with subscapularis tendon injury and medial biceps dislocation.

Strain distribution in the bursal rotator cuff based on whole-muscle and muscle subregion-specific loading: A cadaveric study.

Rotator cuff (RC) tears are common injuries leading to significant dysfunction of the shoulder. Rotator cuff tears alter tension and strain in muscles and tendons. Anatomical studies demonstrated that rotator cuff muscles are comprised of anatomical subregions. However, the strain distribution within the rotator cuff tendons generated from the tension from each anatomical subregion is unknown. We hypothesized that subregions would present distinct 3-dimensional (3D) strain distributions within the rotator cuff tendons, and that the anatomical insertion configuration of the supraspinatus (SSP) and infraspinatus (ISP) tendons might dictate strain, thus tension, transmission. 3D-strains in the bursal side of the SSP and ISP tendons of eight fresh-frozen cadaveric intact shoulders were obtained by applying tension on the whole SSP and ISP muscles, and on their subregions using an MTS system. Strains in the anterior region of the SSP tendon were higher than in the posterior region with whole-SSPanterior-region (p < 0.05) and whole-SSP muscle loading. Higher strains were observed in the inferior half of the ISP tendon with whole-ISP muscle (p < 0.05), middle-subregion (p < 0.01), and superior-subregion (p < 0.05) loading. Tension generating from the posterior-region of the SSP was primarily transmitted to the middle facet via an overlap between the SSP and ISP tendons insertions, while the anterior-region mainly distributed its tension into the superior facet. Tension generating from the middle and superior-regions of the ISP was distributed into the inferior portion of the ISP tendon. These results emphasize the importance of the distinct anatomical subregions of the SSP and ISP muscles in distributing the tension to the tendons.

Muscle Edema of Retraction and Pseudo-Fatty Infiltration After Traumatic Rotator Cuff Tears: An Experimental Model in Sheep.

Traumatic rotator cuff tears can result in retraction of the tendon and may be associated with muscle edema, which may be confused with fatty infiltration as seen on magnetic resonance imaging (MRI). To describe the characteristics of a type of edema associated with acute retraction of the rotator cuff tendon (termed "edema of retraction") and to highlight the risk of mistaking it with pseudo-fatty infiltration of the rotator cuff muscle. Descriptive laboratory study. A total of 12 alpine sheep were used for analysis. On the right shoulder, osteotomy of the greater tuberosity was performed to release the infraspinatus tendon; the contralateral limb acted as the control. MRI was performed immediately after surgery (time zero) and at 2 and 4 weeks postoperatively. T1-weighted, T2-weighted, and Dixon pure-fat sequences were reviewed for hyperintense signals. Edema of retraction resulted in hyperintense signals around or within the retracted rotator cuff muscle on both T1- and T2-weighted imaging, but there was an absence of hyperintense signals on Dixon pure-fat imaging. This represented pseudo-fatty infiltration. Edema of retraction created a characteristic "ground glass" appearance of the muscle on T1-weighted sequences and was often found in either the perimuscular or intramuscular location of the rotator cuff muscle. Compared to time zero values, a decrease in the percentage of fatty infiltration was observed at 4 weeks postoperatively (16.5% ± 4.0% vs 13.8% ± 2.9%, respectively; P < .005). The location of edema of retraction was often peri- or intramuscular. Edema of retraction presented as a characteristic "ground glass" appearance of the muscle on T1-weighted sequences and led to a decrease in the fat percentage because of a dilution effect. Physicians should be aware that this edema can result in a form of pseudo-fatty infiltration, as it is associated with hyperintense signals on both T1- and T2-weighted sequences, and it can be mistaken for fatty infiltration.

Deep Learning Diagnosis and Classification of Rotator Cuff Tears on Shoulder MRI.

Detection of rotator cuff tears, a common cause of shoulder disability, can be time-consuming and subject to reader variability. Deep learning (DL) has the potential to increase radiologist accuracy and consistency. The aim of this study was to develop a prototype DL model for detection and classification of rotator cuff tears on shoulder magnetic resonance imaging into no tear, partial-thickness tear, or full-thickness tear. This Health Insurance Portability and Accountability Act-compliant, institutional review board-approved study included a total of 11,925 noncontrast shoulder magnetic resonance imaging scans from 2 institutions, with 11,405 for development and 520 dedicated for final testing. A DL ensemble algorithm was developed that used 4 series as input from each examination: fluid-sensitive sequences in 3 planes and a sagittal oblique T1-weighted sequence. Radiology reports served as ground truth for training with categories of no tear, partial tear, or full-thickness tear. A multireader study was conducted for the test set ground truth, which was determined by the majority vote of 3 readers per case. The ensemble comprised 4 parallel 3D ResNet50 convolutional neural network architectures trained via transfer learning and then adapted to the targeted domain. The final tear-type prediction was determined as the class with the highest probability, after averaging the class probabilities of the 4 individual models. The AUC overall for supraspinatus, infraspinatus, and subscapularis tendon tears was 0.93, 0.89, and 0.90, respectively. The model performed best for full-thickness supraspinatus, infraspinatus, and subscapularis tears with AUCs of 0.98, 0.99, and 0.95, respectively. Multisequence input demonstrated higher AUCs than single-sequence input for infraspinatus and subscapularis tendon tears, whereas coronal oblique fluid-sensitive and multisequence input showed similar AUCs for supraspinatus tendon tears. Model accuracy for tear types and overall accuracy were similar to that of the clinical readers. Deep learning diagnosis of rotator cuff tears is feasible with excellent diagnostic performance, particularly for full-thickness tears, with model accuracy similar to subspecialty-trained musculoskeletal radiologists.

Evaluation of the Potential of Umbilical Cord Mesenchymal Stromal Cell–Derived Small Extracellular Vesicles to Improve Rotator Cuff Healing: A Pilot Ovine Study

Background: Despite significant advancements in surgical techniques to repair rotator cuff (RC) injuries, failure rates remain high and novel approaches to adequately overcome the natural biological limits of tendon and enthesis regeneration of the RC are required. Small extracellular vesicles (sEVs) derived from the secretome of human multipotent mesenchymal stromal cells (MSCs) have been demonstrated to modulate inflammation and reduce fibrotic adhesions, and therefore their local application could improve outcomes after RC repair. Purpose: In this pilot study, we evaluated the efficacy of clinical-grade human umbilical cord (hUC) MSC-derived sEVs (hUC-MSC-sEVs) loaded onto a type 1 collagen scaffold in an ovine model of acute infraspinatus tendon injury to improve RC healing. Study Design: Controlled laboratory study. Methods: sEVs were enriched from hUC-MSC culture media and were characterized by surface marker profiling. The immunomodulatory capacity was evaluated in vitro by T-cell proliferation assays, and particle count was determined by nanoparticle tracking analysis. Twelve skeletally mature sheep were subjected to partial infraspinatus tenotomy and enthesis debridement. The defects of 6 animals were treated with 2 × 1010 hUC-MSC-sEVs loaded onto a type 1 collagen sponge, whereas 6 animals received only a collagen sponge, serving as controls. Six weeks postoperatively, the healing of the infraspinatus tendon and the enthesis was evaluated by magnetic resonance imaging (MRI) and hard tissue histology. Results: CD3/CD28-stimulated T-cell proliferation was significantly inhibited by hUC-MSC-sEVs (P = .015) that displayed the typical surface marker profile, including the presence of the MSC marker proteins CD44 and melanoma-associated chondroitin sulfate proteoglycan. The local application of hUC-MSC-sEVs did not result in any marked systemic adverse events. Histologically, significantly improved Watkins scores (P = .031) indicated improved tendon and tendon-to-bone insertion repair after sEV treatment and lower postcontrast signal of the tendon and adjacent structures on MRI suggested less residual inflammation at the defect area. Furthermore, the formation of osteophytes at the injury site was significantly attenuated (P = .037). Conclusion: A local, single-dose application of hUC-MSC-sEVs promoted tendon and enthesis healing in an ovine model of acute RC injury. Clinical Relevance: Surgical repair of RC tears generally results in a clinical benefit for the patient; however, considerable rerupture rates have been reported. sEVs have potential as a cell-free biotherapeutic to improve healing outcomes after RC injury.

Tendon Transfers in Rotator Cuff Deficiency

Massive irreparable rotator cuff tears (MIRCT) is a difficult clinical problem to treat in young, active individuals with minimal arthritis. Tendon transfers allow for donation of muscle units that can power the shoulder and restore kinematics. Posterosuperior rotator cuff deficiency can be treated with either a latissimus dorsi tendon or lower trapezius tendon transfer. The authors preferred method for treating irreparable supraspinatus and infraspinatus tears is with an arthroscopic assisted lower trapezius tendon transfer. The advantage of the lower trapezius tendon is that its vector is directly in line with the infraspinatus tendon allowing for better external rotation and abduction moment arms. The tendon is harvested from the spine of the scapula and augmented with an Achilles tendon allograft for length which is then secured at the footprint of the rotator cuff. Anterosuperior rotator cuff deficiency can be treated with a pectoralis major tendon or anterior latissimus tendon transfer. For subscapularis deficiency, our preferred method is an open versus arthroscopic latissimus tendon transfer. The tendon is harvested in the posterior axilla and augmented with an Achilles tendon allograft at the tendon interface to provide bulk. The tendon is passed arthroscopically to the anterior humerus and secured at the lesser tuberosity. Tendon transfers are a safe, reliable and reproducible technique when treating MIRCTs.

Effect of Patient's Positioning on the Grade of Tendinosis and Visible Range of Infraspinatus Tendon on Ultrasound.

To investigate the effect of patient positioning on tendinosis grade, visible range, and infraspinatus tendon (IST) thickness, and to determine the feasibility of internal rotation (IR) position to assess IST on ultrasound (US). This study included 52 shoulders of 48 subjects who were evaluated for IST in three different positions: neutral position (N), IR, and position with the ipsilateral hand on the contralateral shoulder (HC). Two radiologists retrospectively graded IST tendinosis from grade 0 to grade 3 and the visible range from grade 1 to grade 4. The thickness of the IST was measured by another radiologist with a short-axis view. A generalized estimating equation was used for statistical analysis. The tendinosis grades were higher in the HC position than in the IR position, with a cumulative odds ratio of 2.087 (0.004, 95% confidence interval [CI]: 1.268-3.433). The tendinosis grades in the HC position (p = 0.370) and IR position (p = 0.146) were not significantly different from those in the N position. The overall difference in IST thickness was significant (p < 0.001), but the visible range (p = 0.530) was not significantly different according to position. Patient positioning significantly affected the grade of tendinosis and thickness but not the visible range of the IST. The IR position is a feasible position for assessing the IST on US.