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Chronic rotator cuff tears can cause severe functional deficits. Addressing the chronic fatty and fibrotic muscle changes is of high clinical interest; however, the architectural and physiological consequences of chronic tear and repair are poorly characterized. We present a detailed architectural and physiological analysis of chronic tear and repair (both over 8 and 16 wk) compared with age-matched control rabbit supraspinatus (SSP) muscles. Using female New Zealand White Rabbits (n = 30, n = 6/group) under 2% isoflurane anesthesia, the SSP was surgically isolated and maximum isometric force was measured at four to six muscle lengths. Architectural analysis was performed, and maximum isometric stress was computed. Whole muscle length-tension curves were generated using architectural measurements to compare experimental physiology to theoretical predictions. Architectural measures are consistent with persistent radial and longitudinal atrophy over time in tenotomy that fails to recover after repair. Maximum isometric force was significantly decreased after 16 wk tenotomy and not significantly improved after repair. Peak isometric force reported here are greater than prior reports of rabbit SSP force after tenotomy. Peak stress was not significantly different between groups and consistent with prior literature of SSP stress. Muscle strain during contraction was significantly decreased after 8 wk of tenotomy and repair, indicating effects of tear and repair on muscle function. The experimental length-tension data were overlaid with predicted curves for each experimental group (generated from structural data), exposing the altered structure-function relationship for tenotomy and repair over time. Data presented here contribute to understanding the physiological implications of disease and repair in the rotator cuff. NEW & NOTEWORTHY We utilize an established method to measure the length-tension relationship for the rabbit supraspinatus in normal, torn, and repaired muscles. We then perform architectural analysis to evaluate structural changes after tear and repair. Although peak isometric force is lower in the tear and repair groups, there are no differences in peak stresses across groups. These findings indicate persistent structural changes (both radial and longitudinal atrophy) and physiological deficiencies (decreased peak force and uncoupling structure-function relationship) after tenotomy that do not significantly recover after repair.

Background Magnetic resonance imaging (MRI) is standard of care for rotator cuff evaluation, with clinical interpretation usually limited to qualitative judgments. The reliability of MRI-based measurements and scoring systems has been evaluated only preoperatively or ≥6 months following rotator cuff repair, when repairs are in the later stages of healing. This study describes the MRI assessments and inter-rater agreement of various rotator cuff tendon and muscle parameters evaluated preoperatively and 4 times during the first postoperative year. Methods Two musculoskeletal radiologists independently assessed MRI scans of 42 patients preoperatively and 3, 12, 26, and 52 weeks after rotator cuff repair. Using standardized reading rules, readers assessed tendon integrity (5-point Sugaya classification), tear dimensions, muscle fat (5-point Goutallier classification) and atrophy (4-point Warner classification), muscle cross-sectional areas, and myotendinous junction distance. Raw exact agreement proportions, κ statistics, and correlation coefficients were used to quantify inter-rater agreement. Results Readers showed moderate to substantial above-chance agreement in scoring rotator cuff tendon integrity and supraspinatus muscle atrophy and good to excellent agreement on tear dimensions and muscle cross-sectional areas but only fair to moderate agreement for fatty infiltration and myotendinous junction distance. Only fatty infiltration grades evidenced observer bias. Inter-rater agreement did not appear time dependent. Conclusion By use of defined reading rules in a research setting, MRI evaluations of rotator cuff tendon integrity, tear dimensions, muscle atrophy, and cross-sectional areas have reasonable reliability at all time points in the first postoperative year. However, the presence of clinically significant disagreements, even in such favorable circumstances, indicates the need for improved imaging tools for precise rotator cuff evaluation.

Surgical repair of severe rotator cuff tear often results in retear due to unaddressed muscle degeneration. The objective of this study was to test the regenerative potential of micronized dehydrated Human Amnion/Chorion Membrane (dHACM), in a clinically relevant delayed reattachment model of rotator cuff repair. Micronized dHACM was injected into rat supraspinatus muscle during tendon re-attachment surgery, three weeks after original tendon injury. One week after material injection, inflammatory and mesenchymal stem cell infiltration into supraspinatus muscles was assessed via flow cytometry. Histological methods were utilized to assess structural and regenerative changes in muscle one and three weeks after material injection. Micronized dHACM injection resulted in increased M1-like macrophages (17.1 [Formula: see text] fold change over contralateral controls) and regenerating muscle fibers (4.3% vs 1.7% in saline treated muscles) one week after injection compared to saline treated muscles. Tendon reattachment itself exhibited intrinsic healing in this model, demonstrated by a general return of muscle weight and reduced fibrosis. Our results indicate that injection of micronized dHACM may initiate an inflammatory response in degenerated muscle that promotes early muscle regeneration, and that our animal model may be a suitable platform for studying treatments in muscle at early timepoints, before intrinsic healing occurs.

PurposeAnterior insertion of the supraspinatus muscle plays an essential role in rotator cuff tissue. We aimed to determine whether the distance between the midpoints of the supraspinatus central tendon and long head of the biceps tendon on a sagittal shoulder magnetic resonance imaging scan can help to preoperatively diagnose an injury of the anterior insertion of the supraspinatus.MethodThis retrospective study reviewed 103 patients with a full-thickness supraspinatus tendon tear: 50 patients with (injured group) and 53 patients without (intact group) anterior supraspinatus insertion tear. The inter-tendon distance was measured based on an oblique sagittal magnetic resonance imaging scan. SPSS was used for statistical analyses. Two independent samples t-test and receiver operating curve analysis were also performed.ResultsThe measurements of inter-tendon distance revealed good intra- and inter-observer reliabilities with intra-class correlation coefficients of 0.92 and 0.97, respectively. The inter-tendon distance of the injured group was significantly greater than that of the intact group (10.1 ± 2.7 vs 8.0 ± 2.3 mm,P ConclusionThe distance between the supraspinatus central tendon and long head of the biceps tendon on magnetic resonance imaging was greater in patients with anterior supraspinatus insertion injury than those without the injury. A distance of 9 mm may be the cut-off value and a good diagnosis marker for anterior supraspinatus insertion injury.Level of evidenceLevel III, diagnostic case–control study.

This study aimed to compare the effect of the load of the upper limb on the stiffness of supraspinatus muscle regions during isometric shoulder abduction in the scapular plane in healthy individuals and patients with a rotator cuff tear. Thirteen male patients were scheduled for arthroscopic rotator cuff repair, and 13 healthy male individuals were recruited. The movement task involved 30° isometric shoulder abduction in the scapular plane. The tasks included passive abduction, abduction with half-weight of the upper limb (1/2-weight), and full weight of the upper limb (full-weight). The stiffness of the supraspinatus muscle (anterior superficial, anterior deep, posterior superficial, and posterior deep regions) was recorded using ultrasound shear-wave elastography. The stiffness of the anterior superficial region on the affected side was significantly lower than that on the control side for the 1/2-weight and full-weight tasks. The stiffness of the anterior deep, posterior superficial, and posterior deep regions was not affected. This is the first study that investigated the mechanical effects of different loads on different supraspinatus muscle regions in rotator cuff tear patients. Our results indicate that the anterior superficial region in rotator cuff tear patients was mainly responsible for reduced active stiffness. This might be because this region contributes to force exertion and exhibits atrophy in rotator cuff tears. Hence, the anterior superficial region could be a focal point of quantitative dysfunction evaluation of the supraspinatus muscle in the case of a rotator cuff tear.

A few studies have focused on factors predisposing to retear after arthroscopic revision rotator cuff repair (ARRCR). This study aimed to retrospectively evaluate (1) the structural and clinical outcomes of ARRCR and (2) pre- and intraoperative factors affecting the integrity of the rotator cuff (RC) tendon by focusing on preoperative RC tendon integrity, tear size, muscle hypotrophy and fatty infiltration. Patients who underwent ARRCR between 2006 and 2016 were reviewed. Preoperative variables included demographic data, RC tendon integrity, tear size, and muscle hypotrophy and fatty infiltration on preoperative magnetic resonance imaging (MRI). Intraoperative variables included repair technique and completeness of repair. The visual analog scale for pain (PVAS), functional VAS (FVAS), American Shoulder and Elbow Surgeons scores, and shoulder range of motion (ROM) were assessed. Postoperative tendon integrity was evaluated using over 6-month follow-up MRI. Patients were classified into groups A (healed) and B (retear), and their variables were compared. Overall 65 patients with a mean follow-up of 49.5 ± 30.2 (range, 24.0–148.9) months were analyzed. Fifty-six of 65 (86.2%) patients underwent MRI at 9.1 ± 9.7 (range, 4.4–40.2) months after ARRCR, and 20 of 56 (35.7%) patients (group B) exhibited retear. Group A (36/56, 64.3%) showed higher functional scores and ROMs than group B at the final follow-up, with significant differences in the FVAS scores (Group A versus B: FVAS, 7.6 ± 1.8 versus 6.4 ± 1.9, p = 0.036). Intraoperative variables, including preoperative tendon integrity (p = 0.021), tear size (p = 0.007), supraspinatus and infraspinatus muscle hypotrophy and fatty infiltration (p

Rotator cuff disease pathogenesis is associated with intrinsic (e.g., age, joint laxity, muscle weakness) and extrinsic (e.g., mechanical load, fatigue) factors which lead to chronic degeneration of the cuff tissues. However, etiological studies are difficult to perform in patients due to the long duration of disease onset and progression. Therefore, the purpose of this study was to determine the effects of altered joint loading on the rotator cuff. Mice were subjected to one of three load-dependent rotator cuff tendinopathy models: underuse loading, achieved by injecting botulinum toxin-A into the supraspinatus muscle; overuse loading, achieved using downhill treadmill running; destabilization loading, achieved by surgical excision of the infraspinatus tendon. All models were compared to cage activity animals. Whole joint function was assessed longitudinally using gait analysis. Tissue-scale structure and function were determined using microCT, tensile testing, and histology. The molecular response of the supraspinatus tendon and enthesis was determined by measuring the expression of 84 wound healing associated genes. Underuse and destabilization altered forepaw weight bearing, decreased tendon-to-bone attachment strength, decreased mineral density of the humeral epiphysis, and reduced tendon strength. Transcriptional activity of the underuse group returned to baseline levels by 4 weeks, while destabilization had significant upregulation of inflammation, growth factors, and extracellular matrix remodeling genes. Surprisingly, overuse activity caused changes in walking pattern, increased tendon stiffness, and primarily suppressed expression of wound healing related genes. In summary, the tendinopathy models demonstrated how divergent muscle loading can result in clinically relevant alterations in rotator cuff structure, function, and gene expression. This article is protected by copyright. All rights reserved.

Rotator cuff tears are common in the older population. Atrophy and fat infiltration develop un-evenly in torn supraspinatus (SSP) muscles leading to pre- and post-surgical complications. The purpose of the current study was twofold: first, to implement a volumetric and quantitative magnetic resonance imaging (MRI) approach to quantify the degree of muscle atrophy and fat infiltration within the SSP muscle and its four sub-regions (AS, PS, AD, and PD); second to compare 3-D MRI outcomes to the standard 2-D assessment and investigate their relationship with tear size. Fifteen cadaveric shoulders were obtained and MRI performed. Quantitative 3-D outcomes included SSP muscle volume, fossa volume, fat-free muscle volume, and fat fraction for the whole SSP muscle and its four sub-regions. 2-D and qualitative measurements included tear size, 2-D fat infiltration using the Goutallier classification, tangent sign, and occupation ratio. Linear regression outcomes with tear size were not significant for both cross-sectional area (r = − 0.494, p = 0.061) and occupation ratio (r = − 0.011, p = 0.969). Tear size negatively correlated with fat-free muscle volume for both AS and PS sub-regions (AS: r = − 0.78, p

Background Sugaya classification is a widely accepted classification system that is used to analyze postoperative rotator cuff tendon integrity. However, there are inconsistencies in the literature as to whether type 3 Sugaya should be considered as a retear or healed tendon. Purpose We aimed to show that type 3 Sugaya is not a retear by comparing the long-term supraspinatus and infraspinatus muscle degeneration and the functional outcomes of type 3 with those of type 4 and 5 Sugaya. We hypothesized that the clinical course of type 3 Sugaya would be different from type 4 or 5 Sugaya. Method The study was a retrospective multicenter review of all the rotator cuff repair done in 2003-2004. We included all the patients who had undergone supraspinatus repair with 10-year follow-up (magnetic resonance imaging done with full functional assessment). Data collection included pre- and postoperative supraspinatus and infraspinatus fatty infiltration, supraspinatus muscle atrophy, and Constant score with a separate analysis of its Strength subsection. Supraspinatus tendon integrity at 10-year follow-up was determined according to Sugaya classification. The patients were divided into 2 groups: type 3 Sugaya and type 4 and 5 Sugaya. Statistical comparison was done between the groups. Results There was no significant difference in the preoperative fatty infiltration of the supraspinatus and infraspinatus, supraspinatus muscle atrophy, and Constant score between the 2 groups. However, type 3 Sugaya patients had significantly better scores in the preoperative Strength subsection. Postoperatively, type 3 Sugaya patients showed significantly lesser fatty infiltration of the supraspinatus and infraspinatus, lesser supraspinatus muscle atrophy, and higher Constant score compared with type 4 and 5 Sugaya (P Conclusion Patients with type 3 Sugaya supraspinatus tendon exhibited lesser muscle degeneration in the supraspinatus and infraspinatus and performed better in functional assessment compared with type 4 and 5 Sugaya patients. We inferred that type 3 Sugaya should not be considered as a retear.

The rotator cuff (RC) muscles are crucial in moving and stabilizing the glenohumeral joint, and tears can be functionally devastating. Chronic fatty and fibrotic muscle changes, which are nonresponsive to surgical tendon repair, are a focus of contemporary research. The rabbit model recapitulates key biological features of human RC tears, but function and physiology are poorly characterized; limited force and stress data are inconsistent with literature norms in other mammalian species. Here, we present an improved method to assess the physiology of the rabbit supraspinatus muscle (SSP), and we report values for healthy SSP architecture and physiology. Using female New Zealand White Rabbits (

Rotator cuff tears (RCTs) are a common cause of disability and pain in the adult population. Despite the successful repair of the torn tendon, the delay between the time of injury and time of repair can cause muscle atrophy. The goal of the study was to engineer an electroconductive nanofibrous matrix with an aligned orientation to enhance muscle regeneration after rotator cuff (RC) repair. The electroconductive nanofibrous matrix was fabricated by coating Poly(3,4-ethylenedioxythiophene): poly(styrenesulfonate) (PEDOT:PSS) nanoparticles onto the aligned poly(ε-caprolactone) (PCL) electrospun nanofibers. The regenerative potential of the matrix was evaluated using two repair models of RCTs include acute and sub-acute. Sprague–Dawley rats (n=39) were randomly assigned to 1 of 8 groups. For the acute model, the matrix was implanted on supraspinatus muscle immediately after the injury. The repair surgery for the sub-acute model was conducted 6 weeks after injury. The supraspinatus muscle was harvested for histological analysis two and six weeks after repair. The results demonstrated the efficacy of electrical and topographical cues on the treatment of muscle atrophy in vivo. In both acute and sub-acute models, the stimulus effects of topographical and electrical cues reduced the gap area between muscle fibers. This study showed that muscle atrophy can be alleviated by successful surgical repair using an electroconductive nanofibrous matrix in a rat RC model.

Despite the positive effects of botulinum neurotoxin (BoNT) injection into the neural arborized area, there is no anatomical evidence in the literature regarding the neural arborization of the supraspinatus muscle. The present study aimed to define the intramuscular neural arborized pattern of the supraspinatus muscle using the modified Sihler’s staining method to facilitate the establishment of safe and effective injection sites in patients with myofascial pain in the supraspinatus muscle. Seventeen supraspinatus muscles from 15 embalmed cadavers were dissected. Precise suprascapular nerve entry locations were also observed. Intramuscular neural arborization was visualized by Sihler’s staining. The supraspinatus muscle was divided into four portions named A, B, C, and D. The nerve entry points were observed in 88.2% (15 of 17 cases) of section B and 76.5% (13 of 17 cases) of section C of the supraspinatus muscle, respectively. The concentration of intramuscular neural arborization was highest in section B of the supraspinatus muscle, which was the center of the supraspinatus muscle. When the clinician performs a trigger point and a BoNT injection into the supraspinatus muscle, injection within the medial 25–75% of the supraspinatus muscle will lead to optimal results when using small amounts of BoNT and prevent undesirable paralysis.

Background: This study was designed to evaluate characters of the rotator cuff tear (RCT) recognized after primary shoulder dislocation in patients older than 40. Methods: From 2008 to 2019, patients who visited two hospitals after dislocation were retrospectively reviewed. Inclusion criteria were patients over 40 who had dislocation, with magnetic resonance imaging (MRI) undergone. Exclusion criteria were patients who lost to follow-up, combined with any proximal humerus fracture, brachial plexus injury, and previous operation or dislocation history in the ipsilateral shoulder. Also patients who had only bankart or bony bakart lesion in MRI were excluded. We evaluated RCTs that were recognized by MRI after the primary shoulder dislocation with regard to tear size, degree, involved tendons, fatty degeneration, the age when the first dislocation occurred, and the duration until the MRI was evaluated after the dislocation. Results: Fifty-five RCTs were included. According to age groups, the tear size was increased in coronal and sagittal direction, the number of involved tendons was increased, and the degree of fatty degeneration was advanced in infraspinatus muscle. Thirty-two cases (58.2%) conducted MRI after 3 weeks from the first shoulder dislocation event. Conclusions: This group showed that the retraction size of the coronal plane was increased significantly and the fatty accumulation of the supraspinatus muscle had progressed significantly. Age is also a strong factor to affect the feature of RCT after the shoulder dislocation in patients over 40. And the delay of the MRI may deteriorate the degree of tear size and fatty degeneration.

Background Nowadays most of attention regarding rotator cuff is payed to how to reduce the failure after rotator cuff surgical repair rather than how to prevent the rotator cuff tear before surgery. The etiologies of rotator cuff tear are still unclear. As we all know, the nerve system include brain, spinal cord, sensory organs and all the neurons allover our body coordinates the homoeostasis of our body. We hypothesis that the nerve injury proximal to suprascapular nerve can leads to rotator cuff degeneration even tear. Methods Thirty-six SD rats were used. A defect on the suprascapular nerve was made on the right side and a sham surgery on the nerve (expose nerve only) at the left side. The insertion of supraspinatus tendon and supraspinatus muscle were harvested for testing. Twelve rats were sacrificed for biomechanical (six rats) and histological (six rats) properties were evaluated at 3, 6, and 9 weeks after surgery, respectively. Results Significant inferior biomechanical properties of rotator cuff were found in nerve injured side compared to the nerve intact side at 6–9 weeks. Significant muscle atrophy was found at nerve injured side from 3 to 9 weeks. The enthesis of nerve injured side showed significant excessive cell maturity, reduced cellularity, smaller metachromasia area and more type-III collagen especially at 9 weeks after surgery. Conclusions The neuropathy proximal to suprascapular nerve can leads to rotator cuff degeneration even tear. The nerve dysfunction maybe an important etiology for rotator cuff tear.

Chronic shoulder pain (CSP) is one of the most common reasons for seeking medical care. Identifying the specific cause of CSP is necessary to determine the treatment strategy. Objective: to determine which pathology of the musculoskeletal system is the main cause of CSP. Subjects and methods . A study group consisted of 151 patients (49.7% females; mean age, 49.8±18.8 years), who experienced shoulder joint pain that persisted when taking nonsteroidal anti-inflammatory drugs (NSAIDs) and after local administration of glucocorticoids. They underwent clinical and instrumental studies (radiography, magnetic resonance imaging, and ultrasound). The investigators assessed pain intensity using a visual analogue scale (VAS), and functional impairment with the American Shoulder and Elbow Surgeons (ASES) Assessment Scores and the Constant Score (CS). Results and discussion. The mean CSP intensity at rest and during movement was 56.1±21.7 and 67.3±19.1 mm VAS. The degree of functional disorders was 55.5±17.6 ASES scores and 54.1±14.5 CS scores. Tendonitis that is an injury to the tendon of the supraspinatus muscle (74.8%) was most common. There was shoulder osteoarthritis (OA) in 31.7%, acromioclavicular (AC) OA in 19.2%, rotator cuff tendon injury concurrent with shoulder OA in 25.2%, that with AC OA in 16.6%, and that with shoulder OA and AC OA in 9.2%. The intensity of pain with only rotator cuff tendon injury and that concurrent with shoulder OA and/or AC OA did not differ and that averaged 57.2±20.2 and 54.6±18.6 mm at rest, respectively, and 68.3±22.4 and 65.4±19.2 mm during movement (p>0.05 in both cases). Conclusion. The main cause of CSP is tendonitis of the rotator cuff, primarily of the supraspinatus muscle. Moreover, more than half of patients have rotator cuff tendon injury concurrent with biceps tendon injury, shoulder OA and/or AC OA.

BACKGROUND: Muscle atrophy and fatty infiltration (FI) are common occurrences following rotator cuff (RC) tears. Tears of all sizes are subject to muscle degeneration. The degree of muscle degeneration following RC tears is highly correlated with repair success and functional outcomes. We have recently discovered that muscle fibro-adipogenic progenitors (FAPs) can differentiate into uncoupling protein 1 (UCP-1)–expressing beige adipocytes and induce muscle regeneration. This study evaluated the potential of local cell transplantation of beige adipose FAPs (BAT-FAPs) to treat RC muscle degeneration in a murine model of RC repair. METHODS: BAT-FAPs were isolated from muscle in UCP-1 reporter mice by flow cytometry as UCP-1(+)/Sca1(+)/PDGFR(+)/CD31(−)/CD45(−)/integrin α7(−). C57/BL6J mice underwent supraspinatus tendon tear with suprascapular nerve transection followed by repair 2 or 6 weeks after the initial injury. At the time of repair, mice received either no additional treatment, phosphate-buffered saline injection, or BAT-FAP injection. Functional outcomes were assessed by gait analysis. Mice were humanely killed at 6 weeks after cell transplantation. Supraspinatus muscle FI, fibrosis, muscle fiber size, and vascularity were analyzed and quantified via ImageJ. Analysis of variance with post hoc Tukey test and P

Heterotopic ossification is formation of bone in atypical extra-skeletal tissues and usually occurs spontaneously or following neurologic injury with unknown cause. We report a 46-year-old female with right shoulder pain and restricted range of motion (ROM) for 3 months without history of trauma. Magnetic resonance imaging (MRI) showed a lesion within the rotator cuff supraglenoid. Excisional biopsy from a previous institution revealed a heterotopic ossificans (HO ). Following repeat MRI and bone scan, histopathology from arthroscopic resection confirmed an HO. The patient demonstrated improved pain and ROM at follow-up. Idiopathic HO rarely occurs in the shoulder joint, and resection of HO should be delayed until maturation of the lesion to avoid recurrence. The current case showed that arthroscopic HO resection provides an excellent surgical view to ensure complete lesion removal and minimize soft tissue damage at the supraglenoid area. Furthermore, the minimally invasive procedure of arthroscopy may reduce rehabilitation time and facilitate early return to work.

Resumo Objetivo Identificar a correlação clínica, radiológica, e artroscópica das lesões do tendão da cabeça longa do bíceps e sua influência na dor do paciente quando associada às lesões do manguito rotador. Métodos Entre abril e dezembro de 2013, foram avaliados 50 pacientes, sendo 38 (76%) do sexo feminino e 12 (24%) do sexo masculino, com idade média de 65,1 anos. Os pacientes foram operados pelo Grupo de Ombro e Cotovelo da Disciplina de Medicina Esportiva do Departamento de Ortopedia e Traumatologia da Universidade Federal de São Paulo. Os indivíduos foram submetidos a reparo da lesão do manguito rotador com evidência clínica, radiológica e/ou artroscópica de acometimento do tendão da cabeça longa do bíceps. Resultados Observou-se associação entre dor à palpação do sulco intertubercular do úmero com lesão parcial de alto grau (ruptura parcial acometendo mais de 50% do tendão) na artroscopia (p = 0,003). Encontramos ainda uma associação entre a lesão de alto grau da cabeça longa do bíceps e a lesão do tendão do músculo supraespinal (p Conclusão A dor na região anterior do ombro à palpação do sulco intertubercular do úmero pode estar relacionada às lesões de alto grau da cabeça longa do bíceps. A lesão do manguito rotador e o seu tamanho são fatores de risco para lesão de alto grau do tendão da cabeça longa do bíceps.

Pubmed'de indekslenmektedir Introduction: Many factors could affect the supraspinatus (SSP) muscle after tendon rupture. We aimed to determine how infraspinatus and subscapularis tendon problems affect supraspinatus muscle atrophy associated with tears, in a retrospective cohort study conducted in a tertiary-level centre. Materials and Methods: Fifty-eight patients with a full-thickness SSP tendon tear who fulfilled the inclusion criteria were enrolled in the study. They were evaluated for tear retraction, fatty degeneration, and other rotator cuff tendon pathologies. Supraspinatus muscle was assessed using the Goutallier classification, and its average area was also measured. Accompanying lesions of the subscapularis and infraspinatus tendons and degree of supraspinatus muscle atrophy were evaluated using magnetic resonance imaging. Results: Our results showed that supraspinatus tendon tears ranged between 3mm and 41mm, and the estimated average cross-sectional area of the SSP muscle was 247.6mm(2). Any degree of infraspinatus tendon pathology, ranging from tendinosis to full-thickness tears, was significantly correlated with the SSP muscle area (P < 0.05). The subscapularis tendon pathologies did not show a similar correlation. The interobserver and intraobserver reliabilities of the measurements were graded as excellent. Conclusion: Impairment of any of the rotator cuff muscles may affect the other muscles inversely. Our study showed that all infraspinatus tendon pathologies and partial subscapularis tears affect and alter the SSP muscle belly. We suggest early intervention for supraspinatus tears to avoid further fatty degeneration, as muscle atrophy and fatty degeneration progress in combination with the accompanying lesions.

Annotation. Our study is based on data of 444 patients with clinically, MRI diagnosed and then arthroscopically proved diagnosis of the shoulder’s soft tissue injures. Used the following diagnostic tests: “typical pain localization”, shoulder blade rhythm disturbance, “apprehension”, front driver test, compression rotary test, rear driver test, impedance test Nir, Hawkins, weaknesses of withdrawal, weakness of external rotation, “lift off”, “belly press”, “false paralysis”. We have described the most informative and simple clinical tests. Sensitivity and specificity for each clinical test were calculated. Sensitivity and specificity of these tests are statistically adjusted. It has been found that for clinical diagnostics of damage to the anterior-lower lip of the shoulder joint is more diagnostically attractive is the anterior driver test; for diagnosis of damage to the upper lip of the shoulder joint — compression-rotation test, preference is given to the rear “driver test”; for the diagnosis of subacromial conflict syndrome — a combination of two tests: Hawkins test and impingement test; for diagnosis of lesions of the supraspinatus muscle — test of weakness of the abduction; underarm muscle — test of weakness of external rotation; for the diagnosis of total damage to the rotator cuff (RС) — test “falling” hand; the specificity of “belly press” test is higher than the specificity of “Lift off” test when it is impossible to get your hand behind your back. Thus, tests of characteristic localization of pain and disturbance of the shoulder bladder rhythm are sufficient to suspect the patient of the pathology of the shoulder joint complex itself.

Introduction. The proportion of injuries of the rotational cuff is from 65 to 84 % of all injuries of the shoulder joint. This pathology is more often registered in people over 60 years old. It is far from always that during initial visits, patients are given the correct diagnosis. Most patients are treated conservatively with short-term improvement or without dynamics. The main diagnostic method is an MRI of the shoulder joint, where we can see soft tissue structures. The proportion of massive rupture of the tendons of the supraspinatus muscle is 10-40 % of all ruptures of the rotator cuff. The more time passes from the moment of injury to surgical treatment, the more pronounced are the retraction and degenerative changes in tendons. A special category is occupied by patients with chronic rupture of the tendon of the supraspinatus muscle with a retraction of more than 5 cm (Patte grade III) and Thomazeau grade 3 fatty degeneration. In this category of patients, it is not possible to re-insert the tendons of the rotational cuff of the shoulder. Objective: to evaluate the clinical effectiveness of surgical treatment of a patient with retinal tendon retraction (Patte grade III) and Thomazeau grade 3 fatty degeneration. Materials and methods. The clinical case is presented: a man with a chronic total rupture of the tendon of the supraspinatus, infraspinatus muscle (Patte grade III) and Thomazeau grade 3 fatty degeneration. Secondary upper subluxation of the head of the humerus is revealed. The patient underwent surgical treatment: transposition of the latissimus dorsi muscle on the large tubercle of the humerus. Results. Six months after the operation, the patient restored the function of the upper limb, pain was stopped. Conclusion. Given the functional result, transposition of the latissimus dorsi tendon can be considered the technique of choice for inoperable tendon rupture of the supraspinatus muscle.

Purpose Based on its close anatomic features and nearly-collinear force vector to those of supraspinatus muscle, the current article describes a technique of middle trapezius tendon transfer for reproduction of supraspinatus function in the context of rotator cuff irreparability/re-tear management. Methods While seating the patient in beach-chair position, arthroscopic gleno-humeral examination and sub-acromial decompression are initially performed. Hamstring tendons are harvested and fashioned as flattened quadruple sheet. Through McKenzie approach, infraspinatus and subscapularis tendons are repaired. Then, medial half of middle trapezius insertion tendon is harvested from most medial 5-6 cm of the scapular spine. Through McKenzie approach, hamstring sheet is retrieved via a sub-trapezius/sub-acromial corridor from the scapular wound. Hamstring sheet is re-attached to cuff footprint by double row/suture bridge repair configuration. While retracting the scapula and placing gleno-humeral joint in 45O-abduction/45O-external rotation, hamstring sheet is re-attached to released middle trapezius tendon by non-absorbable sutures. Finally, tendon reconstruct is dynamically-tested in different positions of range of motion. Results Transfer of medial portion of middle trapezius insertion tendon (lengthened by interposition hamstring tendon sheet) to cuff footprint was technically feasible. Dynamic testing showed smooth sub-acromial gliding motion of the tendon reconstruct. Conclusion For reproduction of supraspinatus function, hamstring tendon augmented-middle trapezius tendon transfer to cuff footprint heralds a number of technical and biomechanical advantages; thus offering a potential effective modality of cuff irreparability/re-tear management in relatively young patients of high functional demands. However, current description should be investigated in further biomechanical and clinical studies to validate its long-term outcomes.

Occupation ratio and fatty infiltration are important parameters for evaluating patients with rotator cuff tears. We analyzed the occupation ratio using a deep-learning framework and studied the fatty infiltration of the supraspinatus muscle using an automated region-based Otsu thresholding technique. To calculate the amount of fatty infiltration of the supraspinatus muscle using an automated region-based Otsu thresholding technique. The mean Dice similarity coefficient, accuracy, sensitivity, specificity, and relative area difference for the segmented lesion, measuring the similarity of clinician assessment and that of a deep neural network, were 0.97, 99.84, 96.89, 99.92, and 0.07, respectively, for the supraspinatus fossa and 0.94, 99.89, 93.34, 99.95, and 2.03, respectively, for the supraspinatus muscle. The fatty infiltration measure using the Otsu thresholding method significantly differed among the Goutallier grades (Grade 0; 0.06, Grade 1; 4.68, Grade 2; 20.10, Grade 3; 42.86, Grade 4; 55.79, p ρ = − 0.75, p

Background Little is known about the optimal tension in arthroscopic rotator cuff repair (ARCR). This study aimed to identify preoperative, intraoperative, and postoperative factors that correlate with the tension in ARCR and to determine the optimal intraoperative tension using grasper tensioning attachment (GTA), a tension meter attached to the common arthroscopic surgical grasper. Methods Sixty-three patients with a mean age of 65.3 years (range, 45–83 years) at surgery who underwent ARCR were included. The mean follow-up period was 24.1 months (range, 24–28 months). We investigated their demographic data, Japanese Orthopaedic Association score, DeOrio and Cofield classification, and Goutallier stage on the supraspinatus and infraspinatus muscles. We also evaluated the cuff integrity based on the Sugaya classification on magnetic resonance imaging. The free edge of the torn retracted tendon was grasped, and then the passive tension to the footprint was measured with GTA with the arm at the side. The anteroposterior (AP) and mediolateral (ML) diameters were also measured. Results The preoperative Goutallier stages on the supraspinatus muscle were as follows: stage 0, 7 cases; stage 1, 34; stage 2, 20; and stage 3, 2. The mean intraoperative rotator repair tension was 10.0 ± 2.5 N (range, 7.5–17 N). The mean AP diameter of the rotator cuff tear was 22 ± 10 mm (range, 8–50 mm) and the mean ML diameter was 24 ± 10 mm (range, 10–50 mm). Age, DeOrio and Cofield classification, Goutallier stage, and the AP and ML diameters correlated with the rotator repair tension. The rotator repair tension in Sugaya classification type Ⅲ or Ⅳ (n = 12, 11.4 ± 2.4 N) was significantly larger than that in type Ⅰ or Ⅱ (n = 51, 9.7 ± 2.4 N, p = 0.03). A tension ≥10 N as a cutoff value from the receiver operating characteristic curve was a risk factor of poor cuff integrity (95% confidence interval: 0.53–0.88). Conclusions Rotator repair tension ≥10 N was a risk factor of poor cuff integrity. Thus, care should be taken when performing intraoperative procedures and administering postoperative regimens.

Background Rotator cuff (RC) disorders involve a spectrum of shoulder conditions from early tendinopathy to full-thickness tears leading to impaired shoulder function and pain. The pathology of RC disorder is, nonetheless, still largely unknown. Our hypothesis is that a supraspinatus (SS) tendon tear leads to sustained inflammatory changes of the SS muscle along with fatty infiltration and muscle degeneration, which are threshold markers for poor RC muscle function. The aim of this study was to determine the extent of this muscle inflammation in conjunction with lipid accumulation and fibrosis in RC tear conditions. Methods We used proteomics, histology, electrochemiluminescence immunoassay, and quantitative polymerase chain reaction analyses to evaluate inflammatory and degenerative markers and fatty infiltration in biopsies from 22 patients undergoing surgery with repair of a full-thickness SS tendon tear. Results Bioinformatic analysis showed that proteins involved in innate immunity, extracellular matrix organization, and lipid metabolism were among the most upregulated, whereas mitochondrial electronic transport chain along with muscle fiber function was among the most downregulated. Histologic analysis confirmed changes in muscle fiber organization and the presence of inflammation and fatty infiltration. Inflammation appeared to be driven by a high number of infiltrating macrophages, accompanied by elevated matrix metalloprotease levels and changes in transforming growth factor-β and cytokine levels in the SS compared with the deltoid muscle. Conclusions We demonstrated massive SS muscle inflammation after the tendon tear combined with fatty infiltration and degeneration. The regulation of tissue repair is thus extremely complex, and it may have opposite effects at different time points of healing. Inhibition or stimulation of muscle inflammation may be a potential target to enhance the outcome of the repaired torn RC.

A 59 year-old male presented to the county emergency department (ED) in southeastern United States for evaluation of a progressively worsening lump on his left shoulder. He describes it as painful and suggests “it might be a tumor”. There were no other associated complaints. On physical examination, there was a firm, non-tender, non-mobile mass without erythema or warmth, superior to the patient's left acromioclavicular (AC) joint. Both hawkins and empty can test were positive for pain. Point-of-care ultrasound identified a fluid filled structure overlying the AC joint. Initial radiographs demonstrated the so-called geyser sign, a finding of synovial fluid expressed through the AC joint consistent with rotator cuff tear. Subsequent CT scan identified atrophy of the supraspinatus muscle most consistent with rotator cuff tear. This case represents a unique presentation of a chronic rotator cuff tear.

Background Atrophy and fatty infiltration of the rotator cuff muscles portend poor findings in terms of postoperative function and the probability of retears. We assumed that sclerosis and spurs of the greater tuberosity (GT) on radiographs are associated with this rotator cuff muscle degeneration. Methods We retrospectively reviewed the preoperative radiographs and magnetic resonance (MR) images of 91 shoulders (average age of patients, 59.7 years; age range, 36-79 years) arthroscopically repaired between 2012 and 2016. The radiographic morphology of the GT was defined as normal, sclerotic, or spurring. Atrophy and fatty infiltration of the rotator cuff muscles were evaluated using the occupation ratio and Goutallier classification, respectively, via the MR images. Diagnoses of rotator cuff tears were made during arthroscopic shoulder surgery. Results Significant associations between the radiographic GT morphology and the severity of both supraspinatus muscle atrophy ( P = .002) and infraspinatus muscle atrophy ( P = .047) were found. The mean occupation ratios of both the sclerotic GT group and the spurring GT group were significantly reduced compared with the mean occupation ratio of the normal GT group. Patients with GT spurs were found to be prone to severe supraspinatus fatty degeneration ( P = .020). Conclusions For patients with rotator cuff tears, the presence of GT spurs or sclerosis on radiographs predicted the occurrence of supraspinatus and infraspinatus muscle atrophy, as well as supraspinatus fatty infiltration, based on MR images. The clinical relevance is that MR imaging is suggested for patients with radiographic GT sclerosis or spurs to detect advanced rotator cuff lesions.

Background:Muscle atrophy and fatty infiltration are limiting factors for successful rotator cuff (RC) repair. Quantitative data regarding these hallmarks of degenerative muscle changes after RC repair in humans are scarce. By utilizing a new application of the 6-point Dixon magnetic resonance imaging technology, 3-dimensional volume and fat fraction analysis of the whole RC muscle have become possible.Purpose:Quantitative analysis of atrophy and fatty infiltration of the supraspinatus muscle after healed and failed RC tendon-to-bone repair.Study Design:Cohort study; Level of evidence, 3.Methods:Muscle volume and fat fraction were measured preoperatively and at 3 and 12 months postoperatively in 19 failed and 21 healed arthroscopic supraspinatus tendon repairs, with full muscle volume segmentation and magnetic resonance Dixon sequences.Results:In both groups, the muscle volume initially decreased 3 months after RC repair by –3% in intact ( P = .140) and –10% in failed repair ( P = .004) but recovered between 3 and 12 months to 103% ( P = .274) in intact and 92% ( P = .040) in failed repairs when compared with the preoperative volume (difference of change between groups, preoperative to 12 month: P = .013). The supraspinatus muscle’s fat fraction did not significantly change after successful repair (6.5% preoperative, 6.6% after 3 months, and 6.7% after 12 months; all nonsignificant). There was, however, a significant increase from 7.8% to 10.8% at 3 months ( P = .014) and 11.4% at 12 months ( P = .020) after failed repair (difference between groups at 3- and 12-month follow-up: P = .018 and P = .001, respectively).Conclusion:After successful arthroscopic repair, RC tendon tear–induced fatty infiltration can be almost stopped, and muscle atrophy can even be slightly reversed. In case of a failed repair, however, these changes are further pronounced during the first 3 postoperative months but seem to stabilize thereafter.

Purpose When repairing retracted rotator cuff tears, the tear pattern (eg, crescent-shaped, L-shaped) is best determined intraoperatively by evaluating the mobility of the tendon in multiple directions. The purpose of our study was to evaluate the location of the supraspinatus (SSP) muscle belly on magnetic resonance imaging (MRI) in patients undergoing arthroscopic repair of retracted rotator cuff tears. We hypothesized that the location of the rotator cuff muscle would move after tendon repair, and that the perioperative change in muscle position would correlate with the tear pattern. Methods A series of primary arthroscopic repairs for rotator cuff tears with >3 cm of medial retraction from 2015 to 2016 was reviewed. MRIs were performed preoperatively and within 10 days postoperatively. The SSP muscle was assessed on sagittal MRI and evaluated for the "occupation ratio", "tangent sign", and the "location index" proposed in this study. Pre and postoperative MRIs were compared, and correlated with intraoperatively determined tear patterns. Fifty shoulders without rotator cuff pathology were also assessed for the "location index" as control. Results Fifty-nine shoulders (mean age 65.0 years) were included, among which five reverse L-shaped tears were identified. The occupation ratio and tangent sign improved postoperatively. Preoperatively, in the majority of tears, the SSP muscle was located more posteriorly in the SSP fossa, compared to the control group, and shifted anteriorly after repair. However, in reverse L-shaped tears the SSP muscle was located more centrally in the fossa, and shifted posteriorly following repair. Conclusion Rotator cuff tearing and arthroscopic rotator cuff repair change the location of the SSP muscle. Although repair usually results in shifting of the muscle belly from posterior to anterior, reverse L-shaped tears demonstrated an opposite pattern. The location of the SSP muscle belly may be useful in predicting tear patterns of retracted rotator cuff tears. Level of evidence Level IV (case series).

Background The purpose of this study is to determine the pre-operative factors that are associated with reparability of the large-sized and massive rotator cuff tears. Methods Sixty-six patients were included in this prognostic study. Demographic data, radiographic and MRI parameters were collected. Arthroscopic rotator cuff repair was performed for all included patient. Complete rotator cuff repair was achieved when the tendon covered up at least 50% of the anatomical footprint. The receiver operating characteristic (ROC) curve was analysed to define the cut-off level of each significant factor. Results Eleven large-sized rotator cuff tears and fifty-five massive rotator cuff tears were defined from MRI. Fifty-four patients were in the complete repair group, and twelve patients were in the partial repair group. The mean duration between MRI and surgery of 5.5 weeks. Reparability was correlated with age, mediolateral (ML) and anteroposterior (AP) tear size, rotator cuff arthropathy, superior migration of humeral head, fatty infiltration and atrophy of the supraspinatus muscle, and fatty infiltration of infraspinatus muscle (p

The musculoskeletal system is sensitive to its loading environment; this is of particular concern under conditions such as disuse, paralysis, and extended-duration space flight. Although structural and mechanical changes to tendon and bone following paralysis and disuse are well understood, there is a pressing need to understand how this unloading affects the bone-tendon interface (enthesis); the location most prone to tears and injury. We therefore elucidated these effects of unloading in the entheses of adult mice shoulders that were paralyzed for 21 days by treatment with botulinum toxin A. Unloading significantly increased the extent of mechanical failure and was associated with structural changes across hierarchical scales. At the millimeter scale, unloading caused bone loss. At the micrometer scale, unloading decreased bioapatite crystal size and crystallographic alignment in the enthesis. At the nanometer scale, unloading induced compositional changes that stiffened the bioapatite/collagen composite tissue. Mathematical modeling and mechanical testing indicated that these factors combined to increase local elevations of stress while decreasing the ability of the tissue to absorb energy prior to failure, thereby increasing injury risk. These first observations of the multiscale effects of unloading on the adult enthesis provide new insight into the hierarchical features of structure and composition that endow the enthesis with increased resistance to failure. Statement of Significance The musculoskeletal system is sensitive to its loading environment; this is of particular concern under conditions such as disuse, paralysis, and extended-duration space flight. Although changes to tendon and bone following paralysis are understood, there is a pressing need to clarify how unloading affects the bone-tendon interface (enthesis), which is the location most prone to tears and injury. We elucidated the effects of enthesis unloading in adult mice shoulders showing, for the first time, that unloading significantly increased the risk and extent of mechanical failure and was associated with structural changes across hierarchical scales. These observations provide new insight into the hierarchical features of structure and composition that endow the enthesis with resilience. This knowledge can be used to develop more targeted treatments to improve mobility and function.