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Rotator Cuff & Muscles

Rotator cuff muscle pathology, focusing on the prognostic impact of edema, fatty infiltration, and atrophy on surgical outcomes and repairability.

134 citationsUpdated Sep 2026

Overview

Rotator cuff pathology spans a spectrum from isolated full-thickness tears to massive posterosuperior defects, with treatment evolving from conservative management to advanced surgical techniques including arthroscopic repair, muscle transfers, and reversed arthroplasty [32]. Arthroscopic repair remains an effective and safe option for symptomatic tears, providing durable clinical results over time [13]. Long-term data indicate that repair of large or massive tears can yield satisfactory outcomes, with patients maintaining considerable improvements in clinical and radiographic parameters at 10 years [1, 6]. These favorable results extend to patients aged 70 years or older, whose outcomes are comparable to those of younger cohorts at one-year follow-up [8]. However, structural healing does not guarantee functional success; not all patients with healed cuffs experience good outcomes despite high healing rates [15]. Muscle atrophy and fatty infiltration, particularly of the infraspinatus, significantly determine functional outcome after repair [9], and recovery of these degenerative changes rarely occurs with current repair techniques [17]. Supraspinatus muscle shortening further negatively impacts shoulder function, influencing surgical strategy and postoperative recovery [14].

For irreparable massive tears, augmentation strategies and tendon transfers offer viable alternatives, though consensus on the most effective approach for specific scenarios remains lacking [87]. Arthroscopic-assisted latissimus dorsi tendon transfer provides satisfactory functional outcomes [20], although female patients with preoperative generalized muscle weakness face a greater likelihood of poor clinical results [21]. Deltoid transfer also produces acceptable clinical and radiological results [31], while dermal allograft reconstruction demonstrates favorable structural healing and improved range of motion compared to maximal repair in the short term [2]. Conservative management remains an option, with a five-month exercise protocol shown to increase function, reduce pain, and improve quality of life in patients with irreparable tears [86]. Current evidence for massive tear treatment is based on low levels of evidence [28], and high-level, long-term studies are needed to optimize biceps reuse methods for specific tear conditions [48].

Complications and adjunctive considerations require careful management. Deltoid complications combined with rotator cuff pathology represent a rare but devastating complication with no well-described surgical option [4]. Caution is advised regarding corticosteroid injections, which should be withheld if rotator cuff repair is planned within the following 6 months [46]. Isolated SLAP repairs are not always benign, with 1 in 10 patients requiring additional surgery within 3 years, often for rotator cuff, biceps, or distal clavicle disorders [26]. While fatty infiltration and muscle atrophy significantly impact repair outcomes, they do not influence functional outcome after total shoulder arthroplasty [19]. Finally, a multicenter, prospective, observational cohort study is required to confirm or refute findings regarding statin dosing and rotator cuff repair outcomes, as current retrospective data are insufficient to change clinical practice [163].

Anatomy & Pathophysiology

Anatomy

The rotator cuff comprises four muscles: subscapularis, supraspinatus, infraspinatus, and teres minor [33]. The subscapularis inserts into the lesser tuberosity of the humerus, while the supraspinatus, infraspinatus, and teres minor insert into the greater tuberosity [33]. These muscles stabilize the humeral head in the glenoid during deltoid-driven abduction and flexion [33]. The coracoacromial arch, formed by the acromion process, coracoid process, and coracoacromial ligament, is separated from the rotator cuff tendons by the subacromial bursa [33].

Muscle origins and innervation are distinct for each component. The supraspinatus arises from the fossa superior to the scapular spine and is innervated by the suprascapular nerve after it passes through the suprascapular notch [96]. The infraspinatus arises from the fossa below the scapular spine and is innervated by the suprascapular nerve after it passes through the spinoglenoid notch [96]. The subscapularis arises from the anterior aspect of the scapula and is innervated by the upper and lower subscapular nerves [96]. The teres minor arises from the lower lateral aspect of the scapula and is innervated by a branch of the axillary nerve [96].

Histologic studies describe the rotator cuff tendons as having five distinct layers [96]. The most superficial layer consists of coracohumeral ligament fibers oriented obliquely to the muscle axis [96]. The second layer is composed of large bundles extending from the supraspinatus tendon over the biceps groove [96]. The third layer contains smaller, less tightly packed tendon fascicles with less uniform orientation [96]. The fourth layer is composed of loose connective tissue with thick collagen bands that merge with the coracohumeral ligament [96]. The fifth and deepest layer is the continued sheet of collagen fibrils composing the superior joint capsule [96].

There is significant interdigitation and overlap of supraspinatus and infraspinatus tendons near the footprint, with the infraspinatus insertion occupying the preponderance of the footprint on the greater tuberosity [96]. The long head of the biceps tendon attaches to the supraglenoid tubercle and runs between the subscapularis and supraspinatus, kept aligned in the bicipital groove by the coracohumeral ligament and transverse humeral ligament [96].

Specific footprint measurements include a supraspinatus footprint of 13 mm width medial-lateral and 20 mm anteroposterior, and an infraspinatus footprint of 14 mm wide and 20 mm superoinferior [51]. The rotator cable is a thick bundle of fibers running perpendicular to the supraspinatus tendon fibers, connecting the supraspinatus and infraspinatus tendons [51]. This cable is divided into anterior, middle, and posterior segments [97]. The anterior segment forms the lateral part of the rotator interval [97]. The middle portion lies under the supraspinatus tendon [97]. The posterior part is covered by the infraspinatus tendon and ends at the insertion region between the infraspinatus and teres minor tendons [97].

A hypovascular critical zone exists on the articular side of the rotator cuff close to the insertion on the greater tuberosity [51]. Biomechanically, the supraspinatus has a greater mechanical advantage than other tested muscles in the neutral arm position [109]. The supraspinatus and deltoid muscles are equally responsible for producing torque about the shoulder joint in functional planes of motion [103]. The rotator cuff provides substantial anterior dynamic stability to the glenohumeral joint in both end-range and mid-range of motion [128]. In massive rotator cuff tears, the pectoralis major and latissimus dorsi muscles improve glenohumeral kinematics and reduce acromiohumeral pressures [60]. The pectoralis major muscle is not necessary for normal shoulder function but is required for athletics or strenuous activity [79].

Pathophysiology

Rotator cuff tears are a significant cause of shoulder pain and morbidity [5]. The prevalence of full-thickness rotator cuff tears is approximately 25% in patients over 60 years of age and increases to 50% in patients over 80 years of age [5]. Patients with a symptomatic full-thickness rotator cuff tear in one shoulder have a 50% chance of an asymptomatic full-thickness rotator cuff tear in the contralateral shoulder [5]. Subjective mechanical symptoms are a common complaint in patients with suspected rotator cuff pathology [3]. Patients with symptomatic full-thickness rotator cuff tears typically complain of anterolateral shoulder pain radiating into the subdeltoid location [5]. Pain with overhead activity and lifting objects with an outstretched arm is common in symptomatic full-thickness rotator cuff tears [5]. Frequent night pain and sleep disturbance are reported in symptomatic full-thickness rotator cuff tears [5].

Partial-thickness rotator cuff tears have an overall prevalence of 20% in the general population, increasing to 26% in patients older than 60 years [22]. Partial-thickness rotator cuff tears have a limited ability to spontaneously heal [22]. As many as 53% of partial-thickness rotator cuff tears will progress in tear size, and a portion will progress to full-thickness rotator cuff tears [22].

Intrinsic degeneration involves age-related changes in collagen, proteoglycan, water content, and vascularity, usually starting on the articular side [51]. Extrinsic impingement on the coracoacromial arch typically causes tears to start on the bursal side of the tendon [51]. Acute traumatic rotator cuff tears typically occur after a fall and/or dislocation of the shoulder in patients under 40 years of age [51]. Risk factors for rotator cuff tear development include male sex, manual labor, and history of trauma [39]. Additional risk factors include age, smoking, female sex, family history, diabetes, and high cholesterol [51].

Rotator cuff disease is a continuum beginning with mild impingement and progressing through partial tear, full-thickness tear, and massive tear to rotator cuff tear arthropathy [134]. Tears associated with chronic impingement syndrome typically begin on the bursal surface or within the tendon substance [134]. Tears occurring on the articular surface are often due to tension failure in younger athletes participating in overhead activities or intrinsic degeneration [134]. Bursa-side tears are considered more ominous than articular-side tears [134]. As rotator cuff tears increase in size or chronicity, muscle atrophy and fatty infiltration occur [134]. Small full-thickness rotator cuff tears and painful partial-thickness tears become 25% to 50% larger within 3 to 4 years [51]. Larger rotator cuff lesions progress faster than smaller ones [51].

The maximal tensile stress in the supraspinatus tendon is observed on the articular side of the anterior edge at 90 degrees of abduction [161]. The articular side of the rotator cuff is less vascular and has a higher modulus of elasticity, greater stiffness, and a less favorable stress-strain curve compared with the bursal surface [105]. Eccentric forces tend to be concentrated more along the articular surface fibers of the rotator cuff [105]. Shear stress created between tangential and perpendicularly directed forces within the five-layered architecture of the rotator cuff tendon may contribute to intratendinous tear location [105].

Patients with chronic supraspinatus tears have significant reductions in muscle fiber force production [80]. Microscopic muscle atrophy negatively correlates with the movement of abduction, leading to functional impairment [84]. Shoulder pain does not show a relationship with microscopic changes in the supraspinatus tendon and muscle [84]. Muscle shortening negatively impacts shoulder function in torn rotator cuffs [14]. Delayed rotator cuff repair results in persistent muscle atrophy and fatty infiltration [18]. Fatty infiltration and muscle atrophy patterns in chronic rotator cuff tears differ from those in suprascapular neuropathy [40]. Patients with massive rotator cuff tears demonstrate downregulation of fibrogenic, adipogenic, and myogenic genes [45]. Patients with full-thickness rotator cuff tears show upregulation of fibrotic and adipogenic genes [45]. MR imaging-derived rotator cuff muscle proton density fat fraction is associated with isometric strength independent of muscle atrophy and tendon rupture [42]. Myosteatosis and skeletal muscle atrophy are correlated with increasing tear sizes of full-thickness rotator cuff tears [185]. Fibrosis is not correlated with increasing tear sizes of full-thickness rotator cuff tears [185]. The integrity of the inferior subscapularis insertion is the single most important predictor for preserved shoulder function in massive rotator cuff tears [130].

Rotator cuff pathology constitutes up to 60% of all shoulder conditions [107]. Primary impingement results from encroachment of the rotator cuff in the subacromial space, acromial morphologies, or selective hypomobility of noncontractile tissues [107]. Secondary impingement results from microinstability of the glenohumeral joint, ligamentous laxity, inadequate dynamic muscular stabilization, and scapular dysfunction [107]. Internal impingement is commonly involved in overhead athletes when the arm is used in an abducted, externally rotated, and horizontally extended position [107].

The critical shoulder angle correlates with rotator cuff tears and postoperative retears when above 35° to 38° [129]. The critical shoulder angle correlates with osteoarthritis when less than 30° [129]. The acromial index is associated with full-thickness rotator cuff tears and higher retear rates when above 0.7 [129]. Increased lateralization of the acromion and increased superior glenoid inclination may increase the shear forces of deltoid contraction [129]. Genetic predisposition contributes to intrinsic degenerative tendinopathic changes in molecular composition and vascularity, resulting in tendinosis and tearing [129].

Cuff tear arthropathy is the final stage of the shoulder impingement syndrome spectrum [36]. Cuff tear arthropathy affects patients with long-term insufficient massive rotator cuff tears, superior migration of the humeral head, subchondral osteoporosis, humeral head collapse, and painful debilitating shoulder arthritis [36]. Cuff tear arthropathy affects women at a 3:1 female to male ratio [36]. Cuff tear arthropathy more commonly affects patients over 70 years of age [36]. Cuff tear arthropathy more commonly affects the dominant shoulder [36]. Risk factors for cuff tear arthropathy include chronic rotator cuff tears, hemorrhagic shoulder, rheumatic disease, and crystal-induced arthropathy [36]. Mechanical factors in cuff tear arthropathy include insufficient cuff, superior migration of the humeral head, instability, eccentric wear of the glenoid, humeral head deformity, and decreased shoulder function [36]. Nutritional factors in cuff tear arthropathy include hypomobility-induced cartilage atrophy, poor nutrition, dehydration, and subchondral osteoporosis [36]. Crystalline-induced arthropathy in cuff tear arthropathy involves synovial-based matrix protein degradation destroying rotator cuff tendons and cartilage, with end-stage calcium-phosphate crystal deposition [36].

Calcific tendinitis is characterized by a cyclical progression of reactive calcium hydroxyapatite crystal intratendinous deposition followed by spontaneous resorption and healing [137]. Calcific tendinitis most commonly affects the critical zone of relative hypovascularity of the supraspinatus tendon [137]. Calcific tendinitis is the result of a metaplastic cell-mediated transformation of tenocytes into chondrocytes, which then induce calcification [137]. The precalcific stage of calcific tendinitis consists of predominantly fibrocartilaginous metaplasia within less vascular areas of the tendon [118]. In the formative phase of the calcific stage, matrix vesicles unite to form calcium hydroxyapatite deposits separated by fibrocollagenous tissue [118]. The resorption phase of calcific tendinitis involves an inflammatory response and is exquisitely painful [118]. Calcific tendinitis is generally self-limited, with most cases resolving spontaneously [118]. Pain in calcific tendinitis is correlated with macrophage activity during the resorptive phase [118]. The prevalence of calcific tendinitis in a working population is 2.7% [118]. 35% of shoulders with calcific tendinitis are symptomatic [118]. Calcific tendinitis typically affects patients aged 30 to 60 years [118]. Women are more commonly affected by calcific tendinitis than men [118]. The supraspinatus tendon is most often involved in calcific tendinitis [118].

Rotator cuff impingement arises from repetitive compression or rubbing of the tendons under the coracoacromial arch [104]. The impingement position is defined as abduction, slight flexion, and internal rotation [104]. Intrinsic factors for impingement include tendon degeneration, changes in highly sulphated glycosaminoglycans, changes in collagen composition with loading, and changes in vascularity [104]. Extrinsic factors for impingement include spurs growing down the coracoacromial ligament and osteoarthritic thickening of the acromioclavicular joint [104].

Subacromial bursitis refers to inflammation of the subacromial bursa [37]. The supraspinatus tendon is most often initially involved in rotator cuff tendinosis [37]. Rotator cuff tendinosis results from impingement syndrome and is characterized by pain with activity involving overhead motion [37]. The Neer impingement sign involves discomfort when the internally rotated shoulder is moved into forward flexion [37]. Pain relief with a subacromial lidocaine injection is a diagnostic feature of subacromial bursitis and rotator cuff tendinosis [37].

Shoulder pain and conditions affect 16% to 21% of the population [107]. Symptomatic rotator cuff injuries affect up to 30% of the population [53]. The prevalence of full-thickness tears in the aging population is estimated to be as high as 30% [53]. Rotator cuff tendons are intra-articular and intrasynovial [53]. The native fibrocartilaginous insertion of the rotator cuff to the greater tuberosity is not reconstituted during healing [53]. Chronic tendinopathy leads to impaired biological healing capacity on both the tendon and bone side [53]. Factors associated with failure of rotator cuff repair include muscle degeneration, tear size, chronicity, advanced age, and environmental factors [53]. The rotator cuff tends to fail at or near the tendon-bone junction [53]. The goal of rotator cuff repair is to restore the tendon to its anatomic footprint to encourage healing [53]. Progressive understanding of cord, capsule, and cable functional anatomy has optimized rotator cuff outcomes by recognizing the complex dimensionality of the cuff and the load-bearing role of the capsular cable [152].

Human throwing capabilities largely result from derived anatomical features that enable elastic energy storage and release at the shoulder [106]. The rotator cuff muscles act as antagonists after reverse total shoulder arthroplasty [83]. Rotator cuff repair increases deltoid force requirements and joint load after reverse total shoulder arthroplasty, particularly when combined with glenosphere lateralization [83]. Active external rotation after reverse total shoulder arthroplasty is complex and not governed by a single muscle-tendon unit [162]. The transverse force couple is in balance in the Walch type B shoulder in terms of 3D volumetric rotator cuff muscle analysis [144]. The posterior rotator cuff demonstrates increased fatty infiltration in the Walch type B shoulder [144]. Supraspinatus tendon tears combined with Bankart lesions increase humeral rotational range of motion and decrease the force required for dislocation [148]. Both proposed superior labral reconstruction techniques increase the force needed for humeral head superior migration in the setting of a labral tear [142]. Latissimus dorsi transfer most closely approximates the native subscapularis regarding

Classification

Partial-Thickness Tears

Partial-thickness rotator cuff tears are classified by location as articular-sided, bursal-sided, or intratendinous [22]. The Ellman classification grades these tears based on depth: grade 1 involves 3 mm or less, grade 2 involves 3 to 6 mm, and grade 3 involves more than 6 mm of tendon [22]. In this system, grade 3 tears represent tears of more than 50% of tendon width [22]. MRI evaluation similarly classifies partial-thickness tears as low grade or high grade depending on whether they involve less than or more than 50% of the tendon width [22]. A normal rotator cuff is considered to be 10–12-mm thick in the context of partial-thickness tear classification [141].

Specific depth definitions further refine these grades: grade 1 tears are defined as less than 3-mm deep with definite disruption of tendinous fibres [141]. Grade 2 tears are defined as 3–6-mm deep and do not exceed one-half of the thickness of the tendon [141]. Grade 3 tears are defined as more than 6 mm in depth and represent significant disruptions of more than one-half the substance of the cuff [141]. The area of defect for partial-thickness tears is calculated by multiplying the base of the tear by the maximum retraction in square millimeters [141].

Full-Thickness Tears

Full-thickness rotator cuff tears are classified by location and size, with grades including small (<2 cm), large (2–4 cm), massive (>5 cm), and cuff arthropathy [141]. The area of defect for full-thickness tears is calculated by multiplying the length of the base of the tear by the distance of maximum retraction in square centimeters [141]. Cuff arthropathy is defined as a massive tear with articular irregularity, collapse of the humeral head, chronic synovitis, and capsular laxity [141]. Tear size classification for arthroscopic repair includes small (<1 cm), medium (1–3 cm), large (3–5 cm), and massive (>5 cm) tears [92].

Several authors have defined massive rotator cuff tears. Cofield and colleagues defined a massive tear as a tear of 5 cm or more [90]. Burkhart defined a massive tear as one that is at least 5 cm long with no superior coverage [90]. Gerber and colleagues defined a massive tear as one involving the detachment of at least 2 entire tendons [90].

The Patte classification groups full-thickness tears by extent, with group III defined as large or massive tears involving more than 1 tendon and at least 4 cm long in the sagittal plane [90]. Patte classification group IV is defined as massive tears with osteoarthritis of the humeral head [90]. This classification assesses the topography of the tear in the sagittal plane into six segments: segment 1 (subscapularis), segment 2 (coracohumeral ligament), segment 3 (isolated supraspinatus), segment 4 (supraspinatus and one-half of infraspinatus), segment 5 (supraspinatus and infraspinatus), and segment 6 (subscapularis, supraspinatus, and infraspinatus) [55]. The Patte classification also assesses the topography of the tear in the frontal plane [55], the trophic quality of the muscle of the torn tendon [55], and the state of the long head of the biceps [55]. In this system, segment 1 and 2 lesions are considered anterosuperior, segments 2 and 3 are superior, segments 4 and 5 are posterosuperior, and segment 6 is a total-cuff lesion [55]. Medial retraction in the Patte classification is assessed by the position of the torn end of the supraspinatus relative to the glenohumeral joint, with stage 1 indicating little retraction, stage 2 indicating the stump at the level of the humeral head, and stage 3 indicating the stump at the level of the glenoid [91].

Muscle Degeneration and Atrophy

The Goutallier classification grades fatty infiltration of rotator cuff muscles as grade 0 (normal), grade 1 (some fatty streaks), grade 2 (more muscle than fat/less than 50% fatty muscle), grade 3 (equal amounts of muscle and fat/as much fat as muscle), and grade 4 (more fat than muscle) [5, 43, 167]. Goutallier grades 3 and 4 indicate a long-term chronic rotator cuff tear with a higher potential for surgical failure and are likely deemed irreparable [5].

The occupation ratio is a quantitative measure of rotator cuff muscle atrophy determined by dividing the cross-sectional area of the rotator cuff muscle belly by that of the supraspinatus fossa [43]. This ratio standardizes muscle area according to individual body size [43].

The Sugaya classification evaluates post-operative rotator cuff integrity into five types: Type I (sufficient thickness, homogeneously low intensity), Type II (sufficient thickness with partial high-intensity area), Type III (insufficient thickness without discontinuity), Type IV (minor discontinuity in more than one slice), and Type V (major discontinuity on each image) [56]. In this classification, Type IV suggests a small tear and Type V suggests a medium or large tear [56].

Fatty infiltration of the rotator cuff appears as early as 6 weeks after surgical detachment and starts near the musculotendinous junction [7]. Fatty infiltration progresses medially over time and worsens over the course of 1 year in the unrepaired rotator cuff in a rabbit model [7]. Medium fatty infiltration (Goutallier stage 2) appears on average 2 and a half years after the onset of symptoms in rotator cuff tears [30]. Severe fatty infiltration (Goutallier stages 3 and 4) appears at an average of 4 years after symptom onset in rotator cuff tears [30]. Larger tendon tears, longer delays after tendon rupture, and older patient age are associated with more severe and frequent fatty infiltration [30].

Fatty infiltration and muscle atrophy of the rotator cuff do not improve after rotator cuff repair and correlate with poor functional outcome [9]. Recovery of fatty infiltration and muscle atrophy rarely occurs with current rotator cuff repairs [17]. The occupation ratio of the supraspinatus may change after rotator cuff repair without volumetric improvement [91]. Histological evidence supports degeneration and fatty replacement of muscle tissue in chronically torn rotator cuff muscles [93]. Chronic massive rotator cuff tears in rats resulted in a 30% reduction in supraspinatus muscle force and a 35% reduction in infraspinatus muscle force compared with the uninjured side [50]. Patients with a massive rotator cuff tear demonstrate downregulation of fibrogenic, adipogenic, and myogenic genes, indicating the muscle is not in a state of active change [45]. Patients with a full-thickness rotator cuff tear show upregulation of fibrotic and adipogenic genes [45].

The MRI appearance of fatty infiltration and muscle atrophy differs between chronic rotator cuff tears and suprascapular neuropathy, particularly regarding muscle border, degree of perineural fat, and overall distribution of fatty infiltration [40]. Highly specific and characteristic morphological patterns of fatty infiltration exist for both chronic cuff tears and suprascapular neuropathy [40]. B3 glenoids are associated with greater fatty infiltration of all rotator cuff muscles in primary glenohumeral osteoarthritis [85]. The radiographic morphology of the greater tuberosity is associated with muscle degeneration in patients with symptomatic rotator cuff tears [43]. Otsu's thresholding method offers a reliable, objective, and efficient approach for quantifying fatty change in rotator cuff muscles, outperforming the Goutallier classification in terms of inter-rater reliability [182]. Artificial intelligence advancements using in-domain transfer learning, feature fusion, and machine learning classifiers allow for the automated classification of fatty infiltration of rotator cuff muscles on MRI [81]. Quantitative evaluation of the rotator cuff muscles is not well established despite muscular condition predicting patient prognosis [11].

Post-Repair Integrity and Assessment

Twenty-six different criteria described by multiple classification systems have been identified for the magnetic resonance assessment of rotator cuff after repair [34]. Measures of rotator cuff tear size showed stronger associations with re-tear six months post-surgery than measures of tissue quality and concomitant shoulder pathology [16]. Delaminated rotator cuff tears represent chronic degenerative tears with larger sizes and higher fatty infiltration in older patients [188].

Intraoperative prognostic healing factors for rotator cuff repairs include tendon and bone quality and the ability to anatomically reduce and repair the tendon to its normal footprint without undue tension [5]. If anatomic repair cannot be achieved without significant tension, medialised repair can be performed [5]. Goutallier stages III and IV tears accompanied by a tendinous stump of less than 15 mm and a positive tangient sign have a 90% failure rate [5]. Tears with Goutallier grades III and IV are usually deemed irreparable and are treated with alternative strategies such as debridement, tendon transfer, superior capsular reconstruction, or reverse shoulder arthroplasty [5]. Factors associated with failure after rotator cuff repair include larger tears, greater retraction, advanced Goutallier grade, older age, smoking status, osteoporosis, diabetes mellitus, hypercholesterolemia, and more aggressive rehabilitation protocols [5]. The best potential for healing after rotator cuff repair is in patients younger than 70 years with acute, small tears (<3 cm) and a healthy tendon-bone interface who are compliant with sling wear and able to undergo an extended rehabilitation program of 6 to 9 months [5]. Carefully selected patients older than 70 years did well after rotator cuff repair and functionally improved as much as younger patients [5].

The subscapularis tendon is composed of 2 distinct fibrous layers, arranged differently than the supraspinatus tendon [166]. The most common type of subscapularis muscle morphology is three bellies, in line with Larson's model of the division of the subscapularis muscle into three parts [145].

Clinical Presentation

History and Symptoms

Patients with symptomatic full-thickness rotator cuff tears typically report anterolateral shoulder pain radiating to the subdeltoid region [5]. Common complaints include pain during overhead activities and lifting objects with an outstretched arm [5]. Frequent night pain and sleep disturbance are characteristic features [5]. Subjective mechanical symptoms in the affected shoulder are also frequently reported in suspected rotator cuff pathology [3]. In chronic rotator cuff disease, patients often describe an insidious onset of lateral and/or anterior shoulder pain associated with overhead activities [112]. Night pain is a common presenting symptom in these chronic cases [112]. A clear history of trauma resulting in acute pain and weakness strongly suggests an acute rotator cuff tear [112]. A family or personal history of rotator cuff disease increases the likelihood of diagnosis [112].

For subacromial bursitis and rotator cuff tendinosis, mild or moderate pain is present with overhead shoulder motion [37]. Occasional night pain is a clinical finding, as is a history of repetitive overhead activity [37]. Pain is present with activity involving overhead motion, while there is usually no pain or only mild pain with the arm at the side [37]. The patient with rotator cuff tendinosis may occasionally be awakened by pain at night [37].

In rotator cuff tear arthropathy, patients present with chronic shoulder pain, night pain, weakness, and stiffness [36]. Pseudoparalysis is characterized by less than 60º elevation, lack of active external rotation, and incompetent subscapularis [36]. A chronic long head of biceps rupture is usually present [36]. The hornblower sign indicates teres minor insufficiency [36]. The external rotation lag sign is present [36]. Subacromial/glenohumeral crepitus occurs with movement [36]. Range of motion for elevation, external, and internal rotation is very limited [36].

In rotator cuff syndrome, pain is located over the front and lateral aspect of the shoulder with weakness on abduction for supraspinatus involvement, tears of the cuff and tendinitis [33]. Pain is located over the front for biceps pathology [33]. If the cuff or biceps has ruptured, there will also be weakness [33]. In long-standing cases of partial or complete rupture, secondary OA of the shoulder may supervene and movements are then severely restricted [125]. A full-thickness rotator cuff tear may follow a long period of chronic tendinitis, but occasionally it occurs spontaneously after a sprain or jerking injury of the shoulder [125]. With a full-thickness rotator cuff tear, there is sudden pain and the patient is unable to abduct the arm [125]. There is usually wasting of the supraspinatus and infraspinatus [125]. On testing the biceps there may be an old tear of the LHB tendon [125]. There is often tenderness of the acromioclavicular joint [125]. Partial rotator cuff tears may occur within the substance or on the deep surface of the cuff [125]. In partial rotator cuff tears, the remaining cuff fibres permit active abduction with a painful arc [125]. The patient with a rotator cuff tear is usually aged over 45 and gives a history of refractory shoulder pain with increasing stiffness and weakness [125].

Physical Examination

Visual inspection of the shoulder in the upright position at rest and in motion may reveal rotator cuff muscle atrophy, signs of rotator cuff dysfunction, and anterosuperior escape [124]. In rotator cuff tear arthropathy, inspection reveals supraspinatus and infraspinatus atrophy [36]. Inspection also reveals anterior prominence of humeral head with arm elevation (anterosuperior escape) [36]. Subcutaneous effusion is visible on inspection [36]. In subacromial bursitis and rotator cuff tendinosis, no atrophy of the shoulder muscles is present [37].

Passive range of motion assessment can rule out adhesive capsulitis which, if detected, is ideally treated before rotator cuff repair [124]. In subacromial bursitis and rotator cuff tendinosis, active range of shoulder motion may be limited by pain [37]. In rotator cuff tear arthropathy, active and passive range of motion of shoulder is assessed [51].

The Jobe or empty can test isolates the supraspinatus with resistance testing of the arm at 90° of abduction, 30° of flexion in the scapular plane, and thumb pointed down [124]. The external rotation strength test assesses the infraspinatus with the arm in adduction and the elbow at 90° of flexion [124]. The lift-off and belly press tests assess the subscapularis [124]. The external rotation lag sign and hornblower’s sign both assess for massive failure of the infraspinatus and teres minor [124]. The drop arm test examines failure of the superior rotator cuff [124]. No one test for rotator cuff disease has reliably high diagnostic value, rather a combination of tests increases diagnosis specificity [124].

Diagnostic Test Performance: * Empty can test: Sensitivity of 71.7% and specificity of 64.6% for full-thickness supraspinatus tears [112]. Sensitivity of 71% and specificity of 49% for rotator cuff disease [112]. * Lift-off and belly-press tests: High specificity but low sensitivity for full-thickness subscapularis tears [112]. * External rotation lag sign: Sensitivity of 47% and specificity of 94% for full rotator cuff tears [112]. Patients with an external rotation lag sign at the side likely have a large posterosuperior tear involving the infraspinatus [112]. * Internal rotation lag sign: Sensitivity of 97% and specificity of 83% for full rotator cuff tears [112]. * Drop arm test: Sensitivity of 24% and specificity of 93% for rotator cuff disease [112]. * Dropping sign: Sensitivity of 73% and specificity of 77% for full rotator cuff tears [112]. * Gerber (lift-off test): Sensitivity of 34–68% and specificity of 50–77% for rotator cuff disease [112]. * Hawkins test: Sensitivity of 76% and specificity of 48% for rotator cuff disease [112]. * Neer test: Sensitivity of 64–68% and specificity of 30–61% for rotator cuff disease [112]. * Painful arc test: Sensitivity of 71% and specificity of 81% for rotator cuff disease [112]. * Cross-body adduction test: Sensitivity of 75% and specificity of 61% for rotator cuff disease [112]. * Yocum test: Sensitivity of 79% and specificity of 40% for rotator cuff disease [112]. * Passive abduction test: Sensitivity of 74% and specificity of 10% for rotator cuff disease [112]. * External rotation resistance test: Sensitivity of 63% and specificity of 75% for rotator cuff disease [112]. * Full can test: Sensitivity of 75% and specificity of 68% for rotator cuff disease [112]. * Patte test: Sensitivity of 58% and specificity of 60% for rotator cuff disease [112]. * Resisted abduction test: Sensitivity of 58% and specificity of 20% for rotator cuff disease [112]. * Hawkins and Neer tests both positive: Sensitivity of 78% and specificity of 50% for rotator cuff disease [112].

A positive hornblower sign suggests a massive posterosuperior cuff tear that prohibits the active positioning of the hand in space [112]. None of the special tests for shoulder examination are absolutely diagnostic for any one pathologic entity, and many are poorly specific or unreliable if not performed precisely [57].

In subacromial bursitis and rotator cuff tendinosis, manual muscle testing demonstrates mild weakness [37]. When the internally rotated shoulder is moved into forward flexion, the patient will experience discomfort (Neer impingement sign) [37]. Pain resolves and there is a dramatic increase in strength and range of motion with the Neer impingement test after injection of 10 mL of lidocaine into the subacromial space [37].

In rotator cuff tear arthropathy, the deltoid strength and axillary nerve function are assessed [51]. Resisted elevation tests (Jobe, empty can, drop arm sign) assess supraspinatus function [51]. External rotation tests (Lag sign, Patte, hornblower sign) assess infraspinatus/teres minor function [51]. A positive lag sign indicates massive RCT [51]. Internal rotation tests (Belly press, lift-off (Gerber), modified lift-off, bear hug) assess subscapularis function [51]. Cervical spine palpation, range of motion, and Spurling test are used to rule out cervical spine pathologies as cause of shoulder pain [51]. Inspection for muscular atrophy of deltoid and supraspinatus and infraspinatus fossa is performed for chronic RCTs [51]. Palpation of greater tuberosity, acromioclavicular (AC) joint, bicipital groove, and coracoid process is performed [51]. Neer, Hawkins-Kennedy, Yocum, and painful arc tests are impingement signs with low specificity for RCTs [51]. A combination of age >65 years, night pain, and weakness have 95% specificity for RCTs [51]. Weakness is characterized by loss of active elevation and external rotation [51]. Night pain is typical and related to poor outcomes after nonsurgical treatment [51]. Insidious onset of pain on the lateral aspect of shoulder, worse with overhead activities, is part of the history [51].

The diagnosis of long head biceps tendon and subscapularis pathology can be challenging due to limitations in MRI and arthroscopic visualization [38]. Surgeons should maintain a high level of suspicion and utilize specific techniques to prevent missing pathology of the long head biceps tendon and subscapularis [38]. Clinical tests including the O’Brien, Yergason, Speed, and direct palpation tests have limited specificity for biceps pathology [138]. A history of radiating anterior shoulder pain may inform the examiner of pain generation from the long head of the biceps tendon [138]. Arthroscopic examination is limited to the intra-articular long head of the biceps tendon as well as the proximal groove, missing less common distal biceps groove lesions [138]. Subscapularis tendon tears are found in up to 30% of cases often alongside posterosuperior rotator cuff tendon tears [59]. The diagnosis of subscapularis tendon tears can be missed because of the poor sensitivity of clinical examination findings and advanced imaging [59]. About one-third of patients with full-thickness reparable rotator cuff tears are likely to have long head of biceps tendon pathology [72].

Shoulder strength deficits measured via isokinetic testing and shoulder function were weakly correlated in patients with rotator cuff tears overall [78]. Patients with chronic supraspinatus tears have significant reductions in muscle fiber force production [80]. Muscle atrophy and fatty infiltration of the rotator cuff muscles, particularly of the infraspinatus, play a significant role in determining functional outcome after cuff repair [9]. MR imaging–derived rotator cuff muscle proton density fat-fraction is associated with isometric strength independent of muscle atrophy and tendon rupture in shoulders with early and advanced degenerative changes [42]. Supraspinatus muscle shortening negatively impacts shoulder function [14]. Patients with painful shoulders, irrespective of having type 2 diabetes mellitus, seem to have abnormal shoulder muscles [23]. Female patients with poor shoulder function and generalized muscle weakness prior to surgery have a greater likelihood of having a poor clinical result after latissimus dorsi tendon transfer [21].

Despite good healing rates, not all patients with healed rotator cuffs experience good outcomes [15]. Measures of rotator cuff tear size showed stronger associations with re-tear six months post-surgery than measures of tissue quality and concomitant shoulder pathology [16]. Recovery of fatty infiltration and muscle atrophy would rarely occur with current rotator cuff repairs [17]. The clinical and structural outcomes of arthroscopic rotator cuff repair in patients 70 or older with symptomatic full-thickness rotator cuff tear are comparable with those in patients younger than 70 with at least 1-year follow-up [8]. Repair of a large or massive tear of the rotator cuff can have a satisfactory long-term outcome [6]. Patients who had repair of a massive posterosuperior rotator cuff tear maintained considerable improvements in clinical and radiographic outcomes at 10 years [1]. Rotator cuff reconstruction with a dermal allograft demonstrated favorable structural healing rates and improved range of motion compared to maximal repair in the short term [2]. Deltoid complications combined with rotator cuff pathology represent a rare but devastating complication with no well-described surgical option [4]. The physical therapy program was highly effective in alleviating patient symptoms despite the fact that patients continued to have tears of the rotator cuff [75].

Magnetic resonance imaging is useful for the evaluation of patients who have pain and loss of function after a repair of the rotator cuff, particularly for identifying full-thickness tears, intact cuffs, ruptures of the biceps tendon, and detachments of the origin of the deltoid muscle [70]. Magnetic resonance imaging is less effective for partial-thickness tears after repair [70]. Twenty-six different criteria described by multiple classification systems have been identified for the magnetic resonance assessment of rotator cuff after repair [34]. Post-operative rotator cuff integrity based on Sugaya’s classification can reflect abduction muscle strength of the shoulder [56]. The radiographic morphology of the greater tuberosity is associated with muscle degeneration in patients with symptomatic rotator cuff tears [43]. Fatty infiltration of the rotator cuff muscles is closely related to patient age, the extent of the tendon rupture, and the time to onset [25].

Investigations

Plain radiography: Standard views include AP, axillary, and true AP projections [36]. In cuff tear arthropathy, radiographs demonstrate acetabularization of the acromion, femoralization of the humeral head, and eccentric superior glenoid wear [36]. Additional findings include the absence of typical peripheral osteophytes around the humeral head, osteopenia with subarticular sclerosis (snowcap sign), and loss of the coracoacromial arch indicating anterosuperior escape [36]. Chronic rotator cuff disease may present with superior migration of the humeral head and extensive degenerative change [61]. Radiographs may also show spurring and calcification within the acromion or coracoacromial ligament, as well as cystic changes within the greater tuberosity [61]. An acromiohumeral distance shorter than 7 mm on AP radiograph suggests an irreparable tear [61].

MRI: MRI and MRA are both sensitive and specific for full-thickness rotator cuff tears [114]. MRI sensitivity and specificity for full-thickness tears are 92.1% and 92.9%, respectively, while MRA sensitivity and specificity are 95.4% and 98.9% [114]. For partial-thickness tears, MRI sensitivity and specificity are 63.6% and 91.7%, whereas MRA sensitivity and specificity are 85.9% and 96.0% [114]. MRA is more sensitive for detecting partial-thickness, particularly articular-sided tears [114]. Articular-side thickening of the supraspinatus and infraspinatus in the neutral position suggests a partial-thickness articular-side tear [114]. The rotator cable can be reliably identified with the shoulder in the ABER position, even without a tear [114]. MRI characterizes tear location, size, retraction, atrophy, and fatty infiltration [5, 61]. It is particularly effective for identifying full-thickness tears, intact cuffs, biceps tendon ruptures, and deltoid origin detachments [70]. MRI is less effective for identifying partial-thickness tears [70].

Specific MRI Findings and Signs: The tangent sign is defined as failure of the supraspinatus muscle belly to cross a line from the superior border of the coracoid to the superior border of the scapular spine [61]. This sign correlates with supraspinatus atrophy and fatty infiltration [61]. A positive tangent sign predicts repairability and is associated with irreparability of large and massive tears [12, 174]. Tendon retraction to or beyond the glenoid and increased inferior glenohumeral distance are also associated with irreparability [174]. Chronic, retracted tears cause superior humeral head migration, contacting the acromion undersurface and resulting in osseous remodeling (acetabularization) [114].

CT: The Goutallier classification was originally based on CT [61]. CT is helpful to quantify glenoid bone stock when reverse shoulder replacement is considered in advanced arthropathy [36]. Deep learning-based image segmentation provides rapid, reliable automatic quantification of rotator cuff muscle atrophy, fatty infiltration, and degeneration in preoperative CT planning [195]. This automated quantification has higher reliability and similar accuracy compared with human observers [195].

Ultrasound: Ultrasonography is more accurate for full-thickness rotator cuff tears, comparable to MRI [12]. Ultrasound elastography, particularly shear wave elastography, is a promising tool for evaluating mechanical properties of musculoskeletal tissue in the shoulder [77]. It shows potential for detecting and monitoring pathologic processes such as fatty degeneration and tendon tears [77]. Further research is needed to standardize ultrasound elastography techniques and clinical application [77].

Other Considerations: Fatty Infiltration and Muscle Atrophy: The Goutallier classification grades fatty infiltration as grade 0 (normal), grade 1 (fatty streaks), grade 2 (more muscle than fat), grade 3 (equal muscle and fat), and grade 4 (more fat than muscle) [5]. Grades 3 and 4 indicate long-term chronic tears and have a higher potential for surgical failure, often deemed irreparable [5]. Fatty infiltration appears as early as 6 weeks after surgical detachment, starting near the musculotendinous junction and progressing medially [7]. It worsens over 1 year in unrepaired cuffs [7]. Fatty infiltration correlates with patient age, rupture extent, and time to onset [25]. It does not improve after repair and correlates with poor functional outcome [9]. Microscopic muscle atrophy negatively correlates with abduction movement [84]. Increased infraspinatus fatty infiltration correlates with tear severity and supraspinatus atrophy [194]. Teres minor fatty infiltration should be assessed by MRI prior to latissimus dorsi tendon transfer [69]. Preoperative MRI fatty infiltration is not associated with functional outcome after total shoulder replacement [49].

Prognostic Factors and Repairability: Best healing potential exists in patients younger than 70 years with acute, small tears (<3 cm), healthy tendon-bone interface, and compliance with extended rehabilitation [5]. Goutallier stages III and IV tears with a tendinous stump <15 mm and a positive tangent sign have a 90% failure rate [5]. Intraoperative prognostic factors include tendon/bone quality and the ability to repair without undue tension [5]. Patient-reported outcomes and pain do not correlate with structural healing on imaging [63]. Postoperative strength is better in individuals with healed cuffs [63]. Clinical and structural outcomes in patients 70 or older are comparable to younger patients at 1-year follow-up [8]. Massive posterosuperior tear repairs maintain improvements at 10 years [1]. Triple-loaded medially based single-row repair augmented with marrow vents resulted in a 92% healing rate [196].

Prevalence and Natural History: Full-thickness tear prevalence is approximately 25% in patients over 60 years [5]. Symptomatic full-thickness tears have a 50% chance of an asymptomatic contralateral tear [5]. Asymptomatic partial-thickness tear prevalence is 20% [22]. Tear progression correlates with presenting size; 53% of patients showed increased tear size on repeated MRI [24]. Symptoms improve over the first year then plateau [12]. The risk of progression for nonoperatively treated chronic full-thickness tears is approximately 50% at 2 years [5].

Clinical Presentation: Frequent night pain and sleep disturbance are common in symptomatic full-thickness tears [5]. Pain does not correlate with tear severity [24]. No special test is absolutely diagnostic, and many are poorly specific if not performed precisely [57]. Patients with painful shoulders may have abnormal shoulder muscles [23]. Cuff tear arthropathy presents with chronic pain, night pain, weakness, and stiffness [36]. Inspection may reveal supraspinatus/infraspinatus atrophy, anterosuperior escape, and subcutaneous effusion [36]. Range of motion is very limited [36]. Pseudoparalysis is defined as <60º elevation, lack of active external rotation, and incompetent subscapularis [36]. The external rotation lag sign and hornblower sign indicate teres minor insufficiency [36]. Chronic long head of biceps rupture is usually present [36]. Subacromial/glenohumeral crepitus is a clinical finding [36].

Advanced Imaging and AI: Artificial intelligence enables automated classification of fatty infiltration on MRI using transfer learning and machine learning [81]. MR imaging–derived proton density fat-fraction (PDFF) is associated with isometric strength independent of atrophy and rupture [42]. Retear shoulders demonstrate significantly higher preoperative T2 values than intact shoulders [197]. Diagnosis of long head biceps and subscapularis pathology can be challenging due to MRI and arthroscopic limitations [38]. Clinicians may miss rotator cuff tears by not routinely ordering MRI on patients with spontaneous proximal biceps tendon ruptures [44]. B3 glenoids had greater fatty infiltration of all rotator cuff muscles [85]. Patients with CSA >38° and AI >0.7 had higher retear rates but similar functional rates [12]. CSA was higher in patients with tears but did not change over time [12]. CSA and AI do not influence 24-month functional outcome after arthroscopic repair [12]. A large CSA has a higher risk of tendon retear [12]. Supraspinatus atrophy on MRI is independently associated with age, tendon retraction, and histologic myofiber atrophy [187].

Treatment

Non-Operative

Conservative management of rotator cuff pathology typically consists of 6 to 12 weeks of rest and activity modification, symptom management often with NSAIDs, and physical therapy [113]. The physical therapy regimen focuses on passive and active range of motion plus strengthening of scapular stabilizing muscles and the rotator cuff itself [113]. For partial-thickness tears, initial treatment involves activity modification to avoid overhead or pain-provoking activities, a short course of NSAIDs, and directed physical therapy [126]. If these modalities fail, subacromial corticosteroid injections may be considered, particularly for bursal-sided tears [126]. Nonoperative treatment leads to a successful outcome in 60% of patients [5] and is effective in 75% of patients with full-thickness tears after 2 years [41]. In a study of 452 patients with asymptomatic full-thickness tears initially treated nonsurgically, 75% did not require surgery at 2-year follow-up [113]. Asymptomatic full-thickness rotator cuff tears should be treated nonoperatively [61]. Nonoperative treatment is indicated for noncompliant patients, elderly patients (>65 years), patients with medical contraindications to surgery or rotator cuff arthropathy, and athletes with a combined situation of instability and cuff tearing resulting from articular-side partial-thickness failure [61].

Operative

Indications: The primary indication for surgical intervention for rotator cuff tears is significant pain [61]. Chronic full-thickness tears that have failed to respond to nonoperative management may be treated surgically [61]. Full-thickness acute tears should be repaired early because the disease process is accelerated in this setting [61]. In patients with acute, full-thickness rotator cuff tears or chronic, full-thickness rotator cuff tears after failure of nonoperative treatment, rotator cuff repair is indicated [5]. The timing of fixation of acute rotator cuff tears is debated, with a general attempt to repair these within 3 months given reports of inferior outcomes after repair done more than 4 months after injury [5]. Patients can be divided into three main categories for management: those needing urgent or early operative repair, those that can benefit from a trial of conservative treatment, and those that may be best suited for nonoperative treatment [10]. Neither the clinical practice guidelines set out by the American Academy of Orthopaedic Surgeons nor the Cochrane systematic reviews provide guidance on the management of rotator cuff tears [10]. American Academy of Orthopaedic Surgeons Clinical Practice Guidelines indicate only weak evidence supporting surgical repair for chronic full-thickness lesions that have failed nonoperative management [61]. Surgery reliably decreases pain and improves motion and function [61].

Surgical Approach / Technique: The current standard of care for rotator cuff repair is arthroscopic repair [53]. Arthroscopic repair has been shown to have similar outcomes and failure rates compared to open or mini-open repair, with decreased short-term pain and more rapid return to activity [53]. The operative approach for rotator cuff repair has evolved from a classic open approach to a "mini-open" or deltoid-sparing approach and now to an all-arthroscopic technique [61]. Arthroscopic surgery offers advantages over traditional open repair techniques including more thorough visualization, diagnosis, and treatment of lesions within the joint [120]. Arthroscopy allows a more comprehensive assessment of intra-articular pathology and rotator cuff tear configuration by viewing from multiple angles [120]. Tendon mobilization is facilitated by precise releases of adhesions that limit tendon excursion in arthroscopic repair, leading to an improved ability to anatomically reduce the edge and create a tension-free repair [120]. Injury to the deltoid muscle is minimized in arthroscopic repair, and the acromial deltoid origin is preserved, eliminating the risk of deltoid dehiscence [120]. A potential disadvantage of arthroscopic repair historically was the inability to completely mirror the open procedure with regard to fixation options, a concern that has eased with the advent of improved implants, suture materials, suture-passing devices, and techniques [120]. Anatomic footprint restoration is possible in arthroscopic repair with fixation at both the suture-tendon interface and the anchor-bone interface that approximates traditional open transosseous repairs [120].

Implant Selection: Historically, arthroscopic repair was performed using a single row of bone anchors placed within the tuberosity [120]. The double-row technique involves the use of two rows of suture anchors, one medially and one laterally, with the sutures tied separately [120]. Newer arthroscopic techniques involve using a medial row of suture anchors, with suture strands passed medially to a lateral row of anchors in order to compress the tendon down to the bone [120]. In biomechanical studies, double-row repair outperforms single-row repair in failure strength, but superior clinical results with double-row fixation over single-row fixation is still controversial [120]. Surgical techniques have evolved to include double-row and suture-bridge fixation techniques, which have improved biomechanical strength in vitro, though clinical correlation remains controversial [61]. Routine acromioplasty is no longer recommended during rotator cuff repair [61]. Strong fixation of the repair is essential to prevent gapping of the tendon [5].

Other Considerations: The rate-limiting step for recovery after rotator cuff repair is biologic healing of the rotator cuff tendon to the humerus, which is estimated to require a minimum of 8 to 12 weeks [61]. Blood flow to the repaired rotator cuff is achieved from the peribursal tissue and bone anchor site, and vascularity has been shown to increase with exercise [61]. Irreparable tears are more likely to occur when the acromiohumeral distance appears shorter (<7 mm) on AP radiograph [61]. Larger, more retracted tears (>40 mm length/width) are characterized by fatty atrophy and supraspinatus width of less than 5 mm at glenoid margin [61]. Fatty infiltration of the rotator cuff appears as early as 6 weeks after surgical detachment, starts near the musculotendinous junction, and progresses medially over time, worsening over the course of 1 year in the unrepaired rotator cuff [7]. Chronic massive rotator cuff tears in rats resulted in a 30% and 35% reduction in muscle force of the supraspinatus and infraspinatus muscles, respectively, compared with the uninjured side [50]. In massive rotator cuff tear, the pectoralis major and latissimus dorsi muscles are effective in improving glenohumeral kinematics and reducing acromiohumeral pressures [60]. A critical tear area of 175 mm2, which correlates to tear dimensions of approximately 15 mm × 12 mm, was found to be associated with proximal humeral migration [41]. Tears involving the anterior portion of the supraspinatus may need earlier surgical intervention, and tears not involving but close to the cable may need to be more closely monitored if being treated nonoperatively [41].

Outcomes and Long-term Results: Despite good healing rates, not all patients with healed rotator cuffs experience good outcomes [15]. This study established a correlation between improved structural integrity of the repaired cuff tendon and enhanced structural outcomes in rotator cuff muscles [149]. Arthroscopic rotator cuff repair of massive rotator cuff tears with advanced mobilization techniques can lead to reversal of preoperative pseudoparalysis in 90% of patients who have not had previous surgery [189]. All patients with cuff tear arthropathy have a significantly superior position of the humerus compared to the control group [191].

Partial-Thickness Tear Management: Partial-thickness rotator cuff tears have a limited ability to spontaneously heal as shown by histological and radiographic studies [22]. As many as 53% of partial-thickness rotator cuff tears will progress in tear size, and a portion of these will progress to full-thickness rotator cuff tears [22]. Most partial-thickness rotator cuff tears are best initially managed with nonoperative treatment [22]. Surgical treatment with either rotator cuff repair or debridement is indicated for patients in whom nonoperative treatment fails for partial-thickness tears [22]. Most surgeons agree that partial-thickness tears involving more than 50% of tendon width are best treated with repair and those involving less than 50% with debridement and potential decompression [22]. A higher failure rate of debridement has been suggested for partial-thickness bursal-sided rotator cuff tears compared to articular-sided rotator cuff tears, leading some surgeons to favor repair in even low-grade bursal-sided tears [22]. There is no difference in functional outcome scores or re-tear rates between in situ rotator cuff repair and completion to a full-thickness rotator cuff tear with subsequent repair [22]. For partial-thickness tears with poor-quality tendon remaining and involving more than 80% of tendon thickness, debridement is favored [22]. If delamination of the tear is present in articular-side delamination-type tears, a transtendinous repair is indicated [22]. Intratendinous tears that can be identified on MRI must be localized through preoperative planning and use of a spinal needle to identify the tear site [22]. The tear can be opened using an arthroscopic knife and the edge debrided back slightly to promote local healing for intratendinous tears [22]. Extensive debridement is unnecessary for intratendinous rotator cuff tears [22]. Intratendinous rotator cuff tears are repaired side-to-side using arthroscopic technique [22]. The arthroscopic transtendon repair of partial articular-sided rotator cuff tears is an effective procedure that leads to significant improvement in pain and shoulder function, with high patients' satisfaction rate, while the complication rate is low [147]. In a randomized clinical trial of 74 patients with PASTA tears treated with transtendon repair or completion and repair, there was no difference between treatment groups at a minimum of 2-year follow-up [24]. For partial-thickness rotator cuff tears, risk factors for conservative management failure include bursal-sided tears, tears in the dominant upper extremity, and tears involving greater than 50% of the tendon thickness [113]. In a 10-year follow-up study comparing nonsurgical to postoperative management of small and medium size rotator cuff tears, surgical management showed significantly greater improvements of 9.6 points on the Constant and 15.7 points on the American Shoulder and Elbow Surgeons rating score [115].

Irreparable Tears and Salvage Procedures: Fatty infiltration of the teres minor should be assessed by MRI prior to surgery, as it is predictive of the ultimate result for latissimus dorsi tendon transfer [69]. Patch augmented cuff repair leads to a significant improvement of functional and structural outcomes for massive rotator cuff tears with short tendon length [82]. Augmentation strategies may improve outcomes in rotator cuff repairs, particularly in high-risk cases; however, there is a lack of consensus among surgeons on the most effective strategies for each scenario [87]. The article highlights the need for better, well-designed studies truly comparing the outcomes for each of the treatment options used for massive rotator cuff tears, as current evidence is based on low levels of evidence [28]. Salvage options for irreparable cuff tears include superior capsular reconstruction (SCR), tendon transfers, and reverse total shoulder arthroplasty (RTSA) in properly selected and appropriately counseled patients [123]. Studies of high level of evidence and long-term follow-up are needed to explore the most suitable conditions for each long head of biceps (LHB) reuse method and the best method for each specific rotator cuff tear condition [48]. In a biceps-based 3-layer reconstruction of the irreparable rotator cuff, return to heavy-duty/overhead/sports activities is allowed by the 5–6th postoperative month [164].

Rehabilitation and Postoperative Care: Rotator cuff rehabilitation involves specific application of exercise interventions that activate the rotator cuff and scapular musculature at high levels without placing the cuff in positions or movement patterns that promote impingement or instability [67]. It is imperative that both nonsurgical and postoperative rotator cuff rehabilitation begin with a key foundation of scapular stabilization exercises [67]. Weakness or dyskinesis of the scapula is a common clinical finding in patients with rotator cuff disorders, and early rehabilitation and emphasis on the serratus anterior and lower trapezius force couple is recommended [6].

Complications

Re-tear and Structural Failure

Rotator cuff tears are a significant cause of shoulder pain and morbidity, with an overall prevalence of full-thickness tears of approximately 25% in patients over 60 years of age and 50% in patients over 80 years of age [5]. With nonoperative treatment of chronic full-thickness tears, the risk of tear progression is approximately 50% at 2 years [5]. Increased age and longer duration of follow-up were associated with lower healing rates after double-row rotator cuff repair [76]. Ten years following rotator cuff tear repair, between 68 and 81% of tendons had healed, with tears having posterior extension showing a higher risk of retear [146]. Despite good healing rates, not all patients with healed rot cuffs experience good outcomes [15].

Muscle Atrophy and Fatty Infiltration

In a mouse model, delayed rotator cuff repair resulted in persistent muscle atrophy and fatty infiltration [18]. Chronic massive rotator cuff tears in rats resulted in a 30% reduction in muscle force of the supraspinatus and a 35% reduction in muscle force of the infraspinatus compared with the uninjured side [50]. Muscle shortening negatively impacts shoulder function [14]. Infraspinatus fatty infiltration increased significantly in the presence of an infraspinatus tendon tear and when multiple tendons were torn [30]. Medium fatty infiltration appeared on average 2 and a half years after the onset of symptoms, and severe fatty infiltration appeared at an average of 4 years after symptom onset [30]. The ability of the rotator cuff muscles to develop tension correlates with their atrophy and closely correlates with their degree of fatty infiltration [175]. Within 1 year after successful tendon repair, fatty infiltration did not recover, and atrophy improved partially at best [175]. If the rotator cuff repair failed, atrophy and fatty infiltration progressed significantly [175]. With current repair techniques, atrophy and fatty infiltration appear to be irreversible despite successful tendon repair [175].

Postoperative Stiffness and Functional Limitations

Metformin reduces the incidence of shoulder stiffness after arthroscopic rotator cuff repair, with an absolute risk reduction of 12% to 16% at 6 months and 1 year [156]. Metformin does not significantly improve long-term functional scores after arthroscopic rotator cuff repair [156].

Concomitant Pathology and Diagnostic Challenges

About one-third of patients with full-thickness reparable rotator cuff tears are likely to have long head of biceps tendon pathology [72]. Emerging evidence suggests that isolated SLAP repairs are not always benign, with 1 in 10 people needing additional surgery within 3 years, often for disorders of the rotator cuff, biceps, and distal clavicle [26].

Salvage Procedures and Alternative Techniques

In a series of 31 deltoid flap transfers for massive postero-superior rotator cuff tears, survival rates of the deltoid flap were 16.5% at mid-term and 12.5% at long-term follow-up [68]. Cranial migration of the humeral head progressed in all cases of deltoid flap reconstruction and could not be prevented by the interposition of a deltoid flap [68]. Based on results showing minor functional gains and low flap survival, the authors of a 2010 study no longer use nor recommend the deltoid flap technique for massive rotator cuff tears [68]. Female patients with poor shoulder function and generalized muscle weakness prior to surgery have a greater likelihood of having a poor clinical result after latissimus dorsi tendon transfer [21]. In a study of 22 patients undergoing latissimus dorsi transfer for revision massive rotator cuff tears, over 63% reported undergoing 2 or more prior failed rotator cuff repairs [165]. Patients undergoing latissimus dorsi transfer for revision massive rotator cuff tears showed significant improvements in ASES scores from 35.2±21.9 preoperatively to 55.8±22.9 postoperatively [165]. Revision rotator cuff reconstruction improves clinical outcomes and shoulder function at midterm follow-up [47].

Long-Term Outcomes and Prognosis

Between open and arthroscopic repair for severely retracted, large to massive rotator cuff tears, there was no significant difference in detachment of the deltoid origin and alterations of the deltoid muscle after repair [193].

Recovery

Long-term Outcomes and Durability: Arthroscopic rotator cuff repair (ARCR) is an effective and safe option for treating rotator cuff tear symptoms, providing successful clinical results that remain durable over time [13]. In patients aged 70 years or older with symptomatic full-thickness rotator cuff tears, clinical and structural outcomes are comparable to those in patients younger than 70 years, with data supporting this equivalence at least through 1-year follow-up [8].

Structural Healing and Re-tear: For massive rotator cuff tears characterized by short tendon length, patch augmented cuff repair leads to significant improvements in both functional and structural outcomes [82]. Alternatively, arthroscopic rotator cuff repair utilizing interval slide techniques can achieve good clinical outcomes for massive, contracted, and immobile tears [200].

Muscle Degeneration and Prognostic Factors: Fatty infiltration and atrophy of the rotator cuff do not improve following repair and correlate with poor functional outcomes [9]. Infraspinatus fatty infiltration (FI) increases significantly in the presence of an infraspinatus tendon tear, when multiple tendons are torn, with increasing delay between symptom onset and imaging, and with increasing patient age [30]. Medium infraspinatus FI appears on average 2 and a half years after symptom onset, while severe FI appears at an average of 4 years after symptom onset [30]. Consequently, surgical repair should be performed within 2 and a half years after the onset of symptoms to address infraspinatus fatty infiltration [30]. Muscle shortening negatively impacts shoulder function, highlighting potential implications for surgical repair strategies and postoperative recovery [14]. Although muscular condition predicts patient prognosis, quantitative evaluation of rotator cuff muscles is not well established [11]. The degree of tendinopathy did not correlate with the morphological appearance of the tendon, patient outcome, or rotator cuff healing [198].

Key Evidence

• [L4] Patients who had repair of a massive posterosuperior rotator cuff tear maintained considerable improvements in clinical and radiographic outcomes at 10 years. [1] (10.2106/jbjs.17.01190)
• [L1] Rotator cuff reconstruction with a dermal allograft demonstrated favorable structural healing rates and improved range of motion compared to maximal repair in the short term. [2] (10.1016/j.arthro.2019.11.030)
• [L2] Subjective mechanical symptoms in the affected shoulder are a common complaint in patients with suspected rotator cuff pathology. [3] (10.1016/j.jse.2024.02.024)
• [Case_report] Deltoid complications combined with rotator cuff pathology represent a rare but devastating complication with no well-described surgical option. [4] (10.1016/j.jse.2011.09.023)
• [L3] Repair of a large or massive tear of the rotator cuff can have a satisfactory long-term outcome. [6] (10.2106/00004623-199907000-00012)
• [L5] Fatty infiltration of the rotator cuff appears as early as 6 weeks after surgical detachment, starts near the musculotendinous junction, and progresses medially over time, worsening over the course of 1 year in the unrepaired rotator cuff. [7] (10.1016/j.arthro.2007.01.023)
• [L3] The clinical and structural outcomes of ARCR in patients 70 or older with symptomatic full-thickness rotator cuff tear are comparable with those in patients younger than 70 with at least 1-year follow-up. [8] (10.1016/j.arthro.2018.02.047)
• [L2] Muscle atrophy and fatty infiltration of the rotator cuff muscles, particularly of the infraspinatus, play a significant role in determining functional outcome after cuff repair. [9] (10.1177/0363546506297539)
• [Abstract] Although muscular condition predicts the prognosis of the patients, quantitative evaluation of the rotator cuff muscles is not well established. [11] (10.1016/j.jse.2016.11.032)
• [L4] ARCR appears to be an effective and safe option to treat the symptoms of rotator cuff tears and to provide successful clinical results durable with time. [13] (10.1007/s00167-014-3234-8)
• [L3] This suggests that muscle shortening negatively impacts shoulder function and highlights potential implications for surgical repair strategies and postoperative recovery. [14] (10.1016/j.jse.2025.03.002)
• [L3] Despite good healing rates, not all patients with healed rotator cuffs experience good outcomes. [15] (10.1016/j.jse.2021.03.112)
• [L3] Measures of rotator cuff tear size showed stronger associations with re-tear six months post-surgery than measures of tissue quality and concomitant shoulder pathology. [16] (10.1016/j.jse.2013.07.021)
• [L4] Recovery of fatty infiltration and muscle atrophy would rarely occur with current rotator cuff repairs, suggesting further studies and advances in repair strategy are necessary. [17] (10.5397/cise.2019.22.2.59)
• [L5] [18] (10.1177/0363546518793403)
• [L2] There was no influence of the rotator cuff fatty infiltration and muscle atrophy on the functional outcome after total shoulder arthroplasty. [19] (10.1016/j.jse.2017.12.021)
• [L4] Arthroscopic-assisted latissimus dorsi tendon transfer provides satisfactory functional outcomes for irreparable massive rotator cuff tears. [20] (10.1016/j.jse.2015.08.043)
• [L4] Female patients with poor shoulder function and generalized muscle weakness prior to surgery have a greater likelihood of having a poor clinical result. [21] (10.2106/jbjs.f.01160)
• [L3] Patients with painful shoulders, irrespective of having type 2 diabetes mellitus, seem to have abnormal shoulder muscles. [23] (10.1186/s12891-022-05627-9)
• [L4] Fatty infiltration of the rotator cuff muscles is closely related to patient age, the extent of the tendon rupture, and the time to onset. [25] (10.1016/j.otsr.2009.05.001)
• [L5] Emerging evidence suggests that isolated SLAP repairs are not always benign, with 1 in 10 people needing additional surgery within 3 years, often for disorders of the rotator cuff, biceps, and distal clavicle. [26] (10.1016/j.arthro.2016.07.004)
• [L5] The article highlights the need for better, well-designed studies truly comparing the outcomes for each of the treatment options used for massive rotator cuff tears, as current evidence is based on low levels of evidence. [28] (10.1016/j.arthro.2017.01.007)
• [L4] [30] (10.1016/j.jse.2009.12.002)
• [L4] The repair of massive rotator cuff tears by a deltoid transfer produces acceptable clinical and radiological results. [31] (10.1007/s00167-005-0697-7)
• [L5] Treatment of massive rotator cuff tears has evolved from conservative management to advanced surgical techniques including arthroscopic repair, muscle transfers, and reversed arthroplasty. [32] (10.1007/s00167-014-3470-y)
• [L4] Twenty-six different criteria described by multiple classification systems have been identified for the magnetic resonance assessment of rotator cuff after repair. [34] (10.1007/s00167-014-3486-3)
• [L5] Diagnosis of long head biceps tendon and subscapularis pathology in association with shoulder rotator cuff pathology can be challenging due to limitations in MRI and arthroscopic visualization; surgeons should maintain a high level of suspicion and utilize specific techniques to prevent missing pathology. [38] (10.1016/j.arthro.2017.09.005)
• [L4] [40] (10.1016/j.jse.2013.01.028)
• [L3] MR imaging–derived RC muscle PDFF is associated with isometric strength independent of muscle atrophy and tendon rupture in shoulders with early and advanced degenerative changes. [42] (10.1177/0363546517703086)
• [L3] [43] (10.1016/j.jse.2019.03.010)
• [L5] The commentary concludes that a recent case series makes the case that clinicians have been missing a significant number of rotator cuff tears by not routinely ordering MRI on patients with spontaneous proximal biceps tendon ruptures, while noting the need for further data on whether these findings change treatment. [44] (10.1016/j.arthro.2018.01.044)
• [L4] [45] (10.2106/jbjs.m.01585)
• [L1] Caution should be taken when deciding to inject a patient, and this treatment should be withheld if a rotator cuff repair is to be performed within the following 6 months. [46] (10.1016/j.arthro.2019.12.006)
• [L4] Revision RCR improves clinical outcomes and shoulder function at midterm follow-up. [47] (10.1177/0363546518786006)
• [L5] Studies of high level of evidence and long-term follow-up are needed to explore the most suitable conditions for each LHB reuse method and the best method for each specific rotator cuff tear condition. [48] (10.1016/j.arthro.2024.09.019)
• [L4] The degree of fatty infiltration, muscle atrophy and tendinopathy of the rotator cuff muscle on preoperative magnetic resonance imaging scanning is not associated with functional outcome score or functional movement at medium-term follow-up following total shoulder replacement. [49] (10.1177/1758573218811655)
• [L5] Chronic massive rotator cuff tears in rats resulted in a 30% and 35% reduction in muscle force of the supraspinatus and infraspinatus muscles, respectively, compared with the uninjured side. [50] (10.1016/j.jse.2014.04.016)
• [L4] [56] (10.1007/s00167-017-4608-5)
• [L5] None of the special tests for shoulder examination are absolutely diagnostic for any one pathologic entity, and many are poorly specific or unreliable if not performed precisely. [57] (10.1177/03635465030310011101)
• [L4] [59] (10.1016/j.arthro.2019.01.034)
• [L5] In massive rotator cuff tear, the pectoralis major and latissimus dorsi muscles are effective in improving glenohumeral kinematics and reducing acromiohumeral pressures. [60] (10.1016/j.jse.2013.11.030)
• [L4] [68] (10.1016/j.jse.2009.06.005)
• [L4] However, fatty infiltration of the teres minor should be assessed by MRI prior to surgery, as it is predictive of the ultimate result. [69] (10.1016/j.jse.2007.02.128)
• [L3] Magnetic resonance imaging is useful for the evaluation of patients who have pain and loss of function after a repair of the rotator cuff, particularly for identifying full-thickness tears, intact cuffs, ruptures of the biceps tendon, and detachments of the origin of the deltoid muscle, though it is less effective for partial-thickness tears. [70] (10.2106/00004623-199609000-00015)
• [L4] About one-third of patients with full-thickness reparable rotator cuff tears are likely to have LHBT pathology. [72] (10.1016/j.arthro.2017.06.018)
• [L2] The physical therapy program was highly effective in alleviating patient symptoms despite the fact that patients continued to have tears of the rotator cuff. [75] (10.1016/j.jse.2016.04.030)
• [L4] Increased age and longer duration of follow-up were associated with lower healing rates after double-row rotator cuff repair. [76] (10.1177/0363546510382835)
• [L5] Ultrasound elastography, particularly shear wave elastography, is a promising tool for evaluating mechanical properties of musculoskeletal tissue in the shoulder, showing potential for detecting and monitoring pathologic processes such as fatty degeneration and tendon tears, though further research is needed to standardize techniques and clinical application. [77] (10.1016/j.jse.2017.08.001)
• [L3] Shoulder strength deficits measured via isokinetic testing and shoulder function were weakly correlated in patients with rotator cuff tears overall. [78] (10.1016/j.jse.2019.03.015)
• [L4] Patients with chronic supraspinatus tears have significant reductions in muscle fiber force production. [80] (10.1016/j.jse.2014.06.037)
• [L5] This study provides evidence for the effective utilization of artificial intelligence advancements in the automated classification of fatty infiltration of rotator cuff muscles on MRI using in-domain transfer learning, feature fusion, and machine learning classifiers. [81] (10.1016/j.jseint.2025.06.020)
• [L4] Patch augmented cuff repair leads to a significant improvement of functional and structural outcomes. [82] (10.1016/j.jse.2023.03.037)
• [L5] Rotator cuff repair increases deltoid force requirements and joint load, particularly when combined with glenosphere lateralization, suggesting the rotator cuff muscles act as antagonists after reverse total shoulder arthroplasty. [83] (10.1016/j.jse.2016.02.028)
• [L3] Microscopic muscle atrophy appeared to negatively correlate with the movement of abduction leading to functional impairment, while shoulder pain did not show any relationship with microscopic changes. [84] (10.1186/s12891-023-06237-9)
• [L3] B3 glenoids had a greater fatty infiltration of all rotator cuff muscles. [85] (10.1177/17585732241269193)
• [L4] Following a five months exercise protocol patients with irreparable rotator cuff tears showed increased function in their symptomatic shoulder, reduced pain and increased quality of life. [86] (10.1186/s12891-016-1116-6)
• [L4] Augmentation strategies may improve outcomes in rotator cuff repairs, particularly in high-risk cases; however, there is a lack of consensus among surgeons on the most effective strategies for each scenario. [87] (10.2106/jbjs.rvw.25.00007)
• [L4] [90] (10.1016/j.csm.2012.07.008)
• [L3] [91] (10.1177/0363546518758313)
• [L4] [92] (10.1016/j.arthro.2009.07.010)
• [L4] The study provides histological evidence for degeneration and fatty replacement of muscle tissue in chronically torn rotator cuff muscles. [93] (10.1016/j.jse.2016.07.070)
• [L4] The supraspinatus and deltoid muscles are equally responsible for producing torque about the shoulder joint in the functional planes of motion. [103] (10.2106/00004623-198668030-00013)
• [L4] Human throwing capabilities largely result from several derived anatomical features that enable elastic energy storage and release at the shoulder. [106] (10.1038/nature12267)
• [L5] The supraspinatus has a greater mechanical advantage versus the other tested muscles in the neutral arm position. [109] (10.1016/j.jse.2008.10.021)
• [L5] The rotator cuff provided substantial anterior dynamic stability to the glenohumeral joint in the end-range of motion as well as in the mid-range. [128] (10.2106/00004623-200006000-00012)
• [L4] Despite global tear extension, the single most important predictor for preserved shoulder function is the integrity of the inferior subscapularis insertion. [130] (10.1016/j.jse.2014.05.026)
• [L5] Both proposed superior labral reconstruction techniques increased the force needed for humeral head superior migration in the setting of a labral tear. [142] (10.1016/j.arthro.2018.08.049)
• [L4] The transverse force couple is in balance in the Walch type B shoulder in terms of 3D volumetric rotator cuff muscle analysis; however, the posterior rotator cuff does demonstrate increased fatty infiltration. [144] (10.1016/j.jse.2021.02.005)
• [L5] The most common type was the subscapularis muscle with three bellies, in line with Larson's model of the division of the subscapularis muscle into three parts. [145] (10.1155/2021/7450000)
• [L4] Ten years following rotator cuff tear repair, between 68 and 81% of tendons had healed, with tears having posterior extension showing a higher risk of retear. [146] (10.1007/s00167-018-4854-1)
• [L4] The arthroscopic transtendon repair of partial articular-sided rotator cuff tears is an effective procedure that leads to significant improvement in pain and shoulder function, with high patients' satisfaction rate, while the complication rate is low. [147] (10.1007/s00167-015-3953-5)
• [L5] Supraspinatus tendon tears combined with Bankart lesions increased humeral rotational range of motion and decreased the force required for dislocation. [148] (10.1016/j.arthro.2013.05.031)
• [L3] This study established a correlation between improved structural integrity of the repaired cuff tendon and enhanced structural outcomes in rotator cuff muscles. [149] (10.1177/03635465241255944)
• [L5] Progressive understanding of cord, capsule, and cable functional anatomy has optimized rotator cuff outcomes by shifting focus from simple tendon reattachment to recognizing the complex dimensionality of the cuff and the load-bearing role of the capsular cable. [152] (10.1002/arj.70047)
• [L1] Metformin reduces the incidence of shoulder stiffness after arthroscopic rotator cuff repair, with an absolute risk reduction of 12% to 16% at 6 months and 1 year, though it does not significantly improve long-term functional scores. [156] (10.1177/03635465251380296)
• [L2] The maximal tensile stress was observed on the articular side of the anterior edge of the supraspinatus tendon at 90 degrees abduction. [161] (10.1007/s00167-012-2008-4)
• [L4] Active external rotation after reverse total shoulder arthroplasty is complex and not governed by a single muscle-tendon unit. [162] (10.1016/j.jse.2023.08.031)
• [L5] A multicenter, prospective, observational cohort study is required to confirm or refute findings regarding statin dosing and rotator cuff repair outcomes, as current retrospective data are insufficient to change clinical practice. [163] (10.1016/j.arthro.2025.01.019)
• [L4] [164] (10.1186/s13018-023-03978-0)
• [L4] [165] (10.1016/j.arthro.2019.07.034)
• [L5] The subscapularis tendon is composed of 2 distinct fibrous layers, just like the supraspinatus tendon, but arranged differently. [166] (10.1016/j.jse.2018.11.045)
• [L3] [167] (10.1186/s13018-025-05832-x)
• [L3] MRI findings of tendon retraction to or beyond the glenoid, increased inferior glenohumeral distance, and a positive tangent sign are associated with irreparability of large and massive rotator cuff tears. [174] (10.1007/s00167-013-2745-z)
• [L4] [175] (10.1016/j.jse.2007.02.122)
• [L4] Otsu's thresholding method offers a reliable, objective, and efficient approach for quantifying fatty change in rotator cuff muscles, outperforming the Goutallier classification in terms of inter-rater reliability. [182] (10.1016/j.jse.2025.04.026)
• [L4] [185] (10.1016/j.jse.2025.03.040)
• [L3] Supraspinatus muscle atrophy appreciated on MRI is independently associated with patient age, tendon retraction, and atrophy of the supraspinatus myofibers at the histologic level. [187] (10.1177/03635465231173697)
• [L3] Delaminated rotator cuff tears represent chronic degenerative tears with larger sizes and higher fatty infiltration in older patients. [188] (10.1177/0363546518817764)
• [L4] Arthroscopic rotator cuff repair of massive rotator cuff tears with advanced mobilization techniques can lead to reversal of preoperative pseudoparalysis in 90% of patients who have not had previous surgery. [189] (10.1016/j.arthro.2012.02.026)
• [L4] All patients with cuff tear arthropathy have a significantly superior position of the humerus compared to the control group. [191] (10.1016/j.jseint.2023.11.005)
• [L3] Between open and arthroscopic repair for severely retracted, large to massive rotator cuff tears, there was no significant difference in detachment of the deltoid origin and alterations of the deltoid muscle after repair. [193] (10.1177/0363546515603063)
• [L4] Increased infraspinatus fatty infiltration was correlated with the severity of an infraspinatus tear, but substantial fatty infiltration was also seen in the absence of a tear and correlated with worsening severity of a concomitant supraspinatus tear and atrophy. [194] (10.1016/j.arthro.2010.09.014)
• [Abstract] Deep learning-based image segmentation provides a rapid, tireless and reliable automatic quantification of RC muscle atrophy, fatty infiltration, and overall muscle degeneration in patients undergoing preoperative CT planning prior to anatomic or reverse shoulder arthroplasty, with a higher reliability and similar accuracy compared with human observers. [195] (10.1016/j.jse.2022.01.030)
• [L4] Arthroscopic repair of medium to large rotator cuff tears using triple-loaded medially based single-row repair augmented with marrow vents resulted in a 92% healing rate by MRI and excellent patient-reported outcomes. [196] (10.1016/j.arthro.2020.08.003)
• [L2] Retear shoulders demonstrated significantly higher preoperative T2 values than intact shoulders. [197] (10.1016/j.jse.2019.04.036)
• [L3] The degree of tendinopathy did not correlate with morphological appearance of the tendon, patient outcome, or rotator cuff healing. [198] (10.1177/0363546517746986)
• [L4] Arthroscopic rotator cuff repair using interval slide techniques can lead to good clinical outcomes. [200] (10.1007/s00167-013-2683-9)

See Also

• Rotator Cuff
• Rotator cuff repair
• Total shoulder arthroplasty
• Suprascapular neuropathy
• Shoulder Arthritis
• Calcific Tendinitis
• Shoulder Arthroplasty
• Cuff Arthropathy
• Reverse Shoulder Arthroplasty
• Rotator Cuff Disorders

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[197] Relationship between postoperative retear and preoperative fatty degeneration in large and massive rotator cuff tears: quantitative analysis using T2 mapping. Journal of Shoulder and Elbow Surgery. 2019. DOI: 10.1016/j.jse.2019.04.036

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