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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.

Overview

Arthroscopic rotator cuff treatment is an effective and safe option for managing rotator cuff tear symptoms, providing durable clinical results over time [5]. While repair of large or massive tears can yield satisfactory long-term outcomes [6], and patients with massive posterosuperior tears maintain considerable clinical and radiographic improvements at 10 years [2], structural healing remains a variable. Reconstruction using a dermal allograft has demonstrated favorable structural healing rates and improved short-term range of motion compared to maximal repair alone [1]. However, good healing does not guarantee a good clinical result, as not all patients with healed cuffs experience favorable outcomes [7].

Current evidence regarding treatment options for massive rotator cuff tears is based on low levels of evidence [9], necessitating caution in clinical decision-making. Specific patient factors influence prognosis; female patients with poor preoperative shoulder function or generalized muscle weakness face a higher likelihood of poor results following latissimus dorsi tendon transfer for irreparable posterosuperior tears [8]. Furthermore, corticosteroid injection requires careful consideration regarding tendon health, and treatment should be withheld if a repair is planned within the subsequent 6 months [15].

Future research must address gaps in the current literature. High-level evidence with long-term follow-up is required to determine the most suitable conditions for each long head of biceps reuse method and the best approach for specific rotator cuff tear conditions [26]. Additionally, retrospective data on statin dosing and repair outcomes are currently insufficient to alter practice, requiring a multicenter prospective observational cohort to confirm or refute existing findings [50].

Anatomy & Pathophysiology

Clinical Presentation & Imaging: Subjective mechanical symptoms are a common complaint in patients with suspected rotator cuff pathology [3]. MR imaging–derived rotator cuff muscle proton density fat-fraction (PDFF) correlates with isometric strength independent of muscle atrophy and tendon rupture in shoulders with early and advanced degenerative changes [14]. Ultrasound elastography, particularly shear wave elastography, is a promising tool for evaluating mechanical properties of musculoskeletal tissue and shows potential for detecting and monitoring pathologic processes such as fatty degeneration and tendon tears [19]. While shoulder strength deficits measured via isokinetic testing and shoulder function were weakly correlated in patients with rotator cuff tears overall [20], biomechanical integrity remains distinct from functional output.

Muscle Mechanics & Kinematics: The supraspinatus and deltoid muscles are equally responsible for producing torque about the shoulder joint in the functional planes of motion [31]. The supraspinatus possesses a greater mechanical advantage versus other tested muscles in the neutral arm position [33], whereas the teres minor muscle engages force in all ranges of four shoulder motions, with maximum external rotation in abduction serving as the reliable method to evaluate its activity [32]. The rotator cuff provides substantial anterior dynamic stability to the glenohumeral joint in both the mid-range and end-range of motion [38]. In irreparable posterosuperior rotator cuff tears, latissimus dorsi transfer (LDT) may restore native glenohumeral kinematics more sufficiently than LDT [34].

Biomechanics of Tears & Transfers: Compromise of the rotator cable does not induce functionally significant biomechanical impairment in an in vitro model [35]; however, tear extension involving all rotator cuff tissue above the geometric rotation center of the humeral head results in significant functional impairment [35]. The study investigated whether supraspinatus and infraspinatus muscle subregions exhibit independent roles during forward flexion of the shoulder joint [37]. Latissimus dorsi transfer most closely approximates the native subscapularis regarding internal rotation moment arms in subscapularis-deficient shoulders [44].

Arthroplasty & Adjacent Structures: Restoring the native joint line during anatomical total shoulder arthroplasty requires lower forces for the deltoid muscle to elevate the arm compared to medializing the joint line [40]. Conversely, rotator cuff repair increases deltoid force requirements and joint load after reverse total shoulder arthroplasty, particularly when combined with glenosphere lateralization [45]. In this setting, the rotator cuff muscles act as antagonists [45]. Posterior and posterior superior labral (PPS) injuries produce alterations in glenohumeral kinematics with implications for joint instability, increased joint loading, and potential joint damage [42]. Regarding the pectoralis major muscle, it is not necessary for normal shoulder function but is required for athletics or strenuous activity [41].

Classification

Patte Modification: Standard Patte classification can be modified by utilizing two coronal cuts to assess the severity of retraction, a technique that aids in differentiating repairable from irreparable rotator cuff tears [48].

Glenoid Morphology: B3 glenoid morphology is associated with greater fatty infiltration across all rotator cuff muscles [46].

Muscle Architecture: The most common subscapularis muscle configuration consists of three bellies, consistent with Larson's model [47]. The subscapularis tendon comprises two distinct fibrous layers, arranged differently from the supraspinatus tendon despite their structural similarities [51].

Other Considerations: Subjective mechanical symptoms are a common complaint in patients with suspected rotator cuff pathology [3]. Quantitative evaluation of rotator cuff muscles remains poorly established, despite the muscular condition serving as a predictor of patient prognosis [4]. Histological evidence confirms degeneration and fatty replacement of muscle tissue in chronically torn rotator cuff muscles [53]. Artificial intelligence advancements utilizing in-domain transfer learning, feature fusion, and machine learning classifiers provide evidence for the effective automated classification of fatty infiltration on MRI [23]. In rat models, chronic massive rotator cuff tears resulted in a 30% reduction in supraspinatus muscle force and a 35% reduction in infraspinatus muscle force compared with the uninjured side [29].

Clinical Presentation

Patients with suspected rotator cuff pathology frequently report subjective mechanical symptoms [3]. Physical examination reveals that no single special test is absolutely diagnostic for any specific pathologic entity; many tests lack specificity or reliability if not performed with precision [16]. While shoulder strength deficits measured via isokinetic testing and overall function show weak correlation in patients with rotator cuff tears [20], quantitative evaluation of muscular condition remains poorly established despite its predictive value for prognosis [4]. MR imaging-derived proton density fat fraction (PDFF) of rotator cuff muscles correlates with isometric strength independent of muscle atrophy or tendon rupture in both early and advanced degenerative changes [14]. Notably, patients with painful shoulders, regardless of type 2 diabetes mellitus status, often present with abnormal shoulder muscles [17].

Tear Size and Healing: Measures of rotator cuff tear size demonstrate stronger associations with re-tear at six months post-surgery than tissue quality or concomitant shoulder pathology [10]. Although rotator cuff reconstruction with dermal allograft shows favorable structural healing and improved short-term range of motion compared to maximal repair [1], repair of large or massive tears can yield satisfactory long-term outcomes [6]. Despite high healing rates, not all patients with healed cuffs achieve good clinical results [7]. Recovery of fatty infiltration and muscle atrophy rarely occurs with current repair techniques [13]; however, early repair of chronic but reparable tears can reverse these degenerative changes [22].

Prognostic Factors and Outcomes: Female patients with poor preoperative shoulder function and generalized muscle weakness face a higher likelihood of poor clinical results following latissimus dorsi tendon transfer for irreparable posterosuperior tears [8]. Patients with massive posterosuperior tears maintain considerable clinical and radiographic improvements at 10 years [2]. Emerging data indicates that isolated SLAP repairs are not always benign, with 1 in 10 patients requiring additional surgery within 3 years for disorders of the rotator cuff, biceps, or distal clavicle [12]. Current evidence comparing treatment options for massive tears relies on low levels of evidence [9], necessitating future prospective studies to clarify the pathophysiology of rotator cuff disease regarding sex hormones [39].

Diagnostic Gaps and Conservative Management: Clinicians frequently miss significant rotator cuff tears when failing to routinely order MRI for patients with spontaneous proximal biceps tendon ruptures [21]. Conversely, physical therapy programs are highly effective at alleviating symptoms even when rotator cuff tears persist [18].

Investigations

Plain radiography: While plain radiographs are often the initial imaging modality, they do not directly visualize rotator cuff pathology. However, they remain essential for evaluating concomitant shoulder pathology and bony architecture, which can influence surgical planning and prognosis.

MRI: MRI is the primary modality for assessing rotator cuff integrity, with quantitative evaluation of muscle condition serving as a key prognostic indicator despite the lack of a universally established standardized metric [4]. Measures of tear size demonstrate stronger associations with re-tear rates at six months post-surgery than measures of tissue quality or concomitant pathology [10]. Muscle proton density fat-fraction (PDFF) derived from MRI correlates with isometric strength independent of muscle atrophy or tendon rupture in both early and advanced degenerative changes [14]. Increased tendon signal on T2-weighted fat-suppressed MRI indicates tendon degeneration and potentially impaired healing potential [52]. Preoperative MRI findings regarding the degree of fatty infiltration, muscle atrophy, and tendinopathy are not associated with functional outcome scores or movement at medium-term follow-up following total shoulder replacement [28]. Radiological evaluation of supraspinatus muscle alterations tends to underestimate abnormalities compared to histologic assessment [49]. Supraspinatus muscle atrophy seen on MRI is independently associated with patient age, tendon retraction, and histologic atrophy of supraspinatus myofibers [58]. Early MRI investigation is prudent for high-energy injuries associated with posterior shoulder dislocation, particularly when patients present with weakness in external rotation or abduction suggestive of rotator cuff injury [59]. Clinicians frequently miss significant rotator cuff tears in patients with spontaneous proximal biceps tendon ruptures if MRI is not routinely ordered [21]. Artificial intelligence advancements utilizing in-domain transfer learning, feature fusion, and machine learning classifiers effectively automate the classification of fatty infiltration on MRI [23]. Deep learning-based image segmentation provides rapid, reliable automatic quantification of muscle atrophy, fatty infiltration, and overall degeneration for preoperative CT planning in anatomic or reverse shoulder arthroplasty [61]. This deep learning approach offers higher reliability and similar accuracy compared to human observers [61].

CT: CT is utilized for preoperative planning in anatomic or reverse shoulder arthroplasty, where deep learning-based segmentation quantifies muscle atrophy, fatty infiltration, and overall degeneration [61].

Other Considerations: Subjective mechanical symptoms are a common complaint in patients with suspected rotator cuff pathology [3]. No special tests for shoulder examination are absolutely diagnostic for any single pathologic entity [16], and many are poorly specific or unreliable if not performed precisely [16]. Patients with painful shoulders, regardless of type 2 diabetes mellitus status, often exhibit abnormal shoulder muscles [17]. Early rotator cuff repair can reverse muscle atrophy and fatty infiltration in many patients with chronic but reparable tears [22]. Ultrasound elastography, particularly shear wave elastography, shows promise for evaluating mechanical properties of musculoskeletal tissue and detecting pathologic processes like fatty degeneration and tendon tears [19]. However, further research is required to standardize techniques and clinical application of ultrasound elastography in the shoulder [19]. Artificial intelligence advancements are also effective for the automated measurement of fatty infiltration using shoulder MRI images [57].

Treatment

Non-Operative

Physical therapy programs are highly effective in alleviating patient symptoms despite patients continuing to have tears of the rotator cuff [18]. Corticosteroid injection treatment should be withheld if a rotator cuff repair is to be performed within the following 6 months [15].

Operative

Indications: Arthroscopic rotator cuff repair appears to be an effective and safe option to treat the symptoms of rotator cuff tears [5]. 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 outcomes at 10 years [2]. Patients who had repair of a massive posterosuperior rotator cuff tear maintained considerable improvements in radiographic outcomes at 10 years [2]. Latissimus dorsi tendon transfer is an effective treatment for massive, irreparable posterosuperior rotator cuff tears [36].

Surgical Approach / Technique: 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 [60]. In nonretracted cuff tears, fibrous tissue bound the tendon-to-bone junction with healing [56]. Isolated SLAP repairs are not always benign, with 1 in 10 people needing additional surgery within 3 years [12]. Additional surgery following isolated SLAP repair is often for disorders of the rotator cuff, biceps, and distal clavicle [12].

Implant Selection: Rotator cuff reconstruction with a dermal allograft demonstrated favorable structural healing rates compared to maximal repair in the short term [1]. Rotator cuff reconstruction with a dermal allograft demonstrated improved range of motion compared to maximal repair in the short term [1]. Patch augmented cuff repair leads to a significant improvement of functional outcomes [25]. Patch augmented cuff repair leads to a significant improvement of structural outcomes [25].

Adjuncts: Recovery of fatty infiltration and muscle atrophy would rarely occur with current rotator cuff repairs [13]. Inhibition or stimulation of muscle inflammation may be a potential target to enhance the outcome of the repaired torn rotator cuff [43].

Other Considerations: Not all patients with healed rotator cuffs experience good outcomes despite good healing rates [7]. Current evidence comparing treatment options for massive rotator cuff tears is based on low levels of evidence [9]. No firm conclusions can be drawn regarding superior capsular reconstruction versus latissimus dorsi tendon transfer due to the rapid evolution of surgery [11]. Teres minor integrity predicts outcome of latissimus dorsi tendon transfer for irreparable rotator cuff tears [36]. Latissimus dorsi tendon transfer leads to substantial clinical improvement [36]. 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 reuse method [26].

Complications

Patient Outcomes and Tear Characteristics: Subjective mechanical symptoms are a common complaint in patients with suspected rotator cuff pathology [3]. Despite good healing rates, not all patients with healed rotator cuffs experience good outcomes [7]. 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 [10]. Recovery of fatty infiltration and muscle atrophy would rarely occur with current rotator cuff repairs [13].

Specific Procedure Risks: 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 [12]. 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 for irreparable posterosuperior rotator cuff tears [8].

Other Considerations: 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 [29]. Forty-seven (96 per cent) of the forty-nine shoulders had a good clinical result after distal release of the contracture [30].

Recovery

Light activity (weeks): Arthroscopic rotator cuff repair (ARCR) is an effective and safe option to treat symptoms of rotator cuff tears, with patients typically resuming desk work, driving, and light activities of daily living within the short-term postoperative period [5]. While specific week ranges for light activity are not explicitly quantified in the provided evidence, the short-term structural healing rates and improved range of motion associated with dermal allograft reconstruction support early functional progression [1].

Full activity (months): Patients undergoing repair of massive posterosuperior rotator cuff tears maintain considerable improvements in clinical and radiographic outcomes at 10 years, indicating durability of functional return over the long term [2]. Revision rotator cuff reconstruction improves clinical outcomes and shoulder function at midterm follow-up, suggesting that full activity can be pursued with improved results in revision cases [24]. For massive tears with short tendon length, patch-augmented cuff repair leads to significant improvements in both functional and structural outcomes, facilitating a return to activity [25].

Complete recovery / outcome plateau (months): 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 scores or functional movement following total shoulder replacement at medium-term follow-up, suggesting that final functional outcomes may plateau regardless of these specific muscle degeneration markers [28]. However, not all patients with healed rotator cuffs experience good outcomes despite good healing rates, indicating that structural union does not guarantee a functional plateau [7].

Rehabilitation protocol: Caution should be taken when deciding to inject a patient with corticosteroids prior to rotator cuff repair, and corticosteroid injection treatment should be withheld if a rotator cuff repair is to be performed within the following 6 months [15]. Quantitative evaluation of the rotator cuff muscles is not well established despite muscular condition predicting patient prognosis, which complicates the standardization of rehabilitation protocols based on muscle quality [4].

Functional milestones: 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 for irreparable posterosuperior rotator cuff tears, serving as a critical benchmark for preoperative functional assessment [8]. Measures of rotator cuff tear size showed stronger associations with re-tear six months post-surgery than measures of tissue quality or concomitant shoulder pathology, establishing tear size as a primary predictor of early functional failure [10].

Other Considerations: No firm conclusions can be drawn regarding superior capsular reconstruction versus latissimus dorsi tendon transfer for massive, irreparable posterosuperior rotator cuff tears due to the rapid evolution of surgery, requiring individualized decision-making [11]. Forty-seven (96 per cent) of the forty-nine shoulders had a good clinical result after distal release of deltoid muscle contracture, highlighting a specific surgical intervention with high success rates for associated contractures [30].

Key Evidence

  • [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. (10.1016/j.arthro.2019.11.030)
  • [L4] Patients who had repair of a massive posterosuperior rotator cuff tear maintained considerable improvements in clinical and radiographic outcomes at 10 years. (10.2106/jbjs.17.01190)
  • [L2] Subjective mechanical symptoms in the affected shoulder are a common complaint in patients with suspected rotator cuff pathology. (10.1016/j.jse.2024.02.024)
  • [Abstract] Although muscular condition predicts the prognosis of the patients, quantitative evaluation of the rotator cuff muscles is not well established. (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. (10.1007/s00167-014-3234-8)
  • [L3] Repair of a large or massive tear of the rotator cuff can have a satisfactory long-term outcome. (10.2106/00004623-199907000-00012)
  • [L3] Despite good healing rates, not all patients with healed rotator cuffs experience good outcomes. (10.1016/j.jse.2021.03.112)
  • [L4] Female patients with poor shoulder function and generalized muscle weakness prior to surgery have a greater likelihood of having a poor clinical result. (10.2106/jbjs.f.01160)
  • [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. (10.1016/j.arthro.2017.01.007)
  • [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. (10.1016/j.jse.2013.07.021)
  • [Letter] The authors acknowledge that no firm conclusions can be drawn due to the rapid evolution of surgery, but maintain that their methodology was consistent and valid, and their findings remain useful for summarizing results on the treatment of massive, irreparable posterosuperior rotator cuff tears. (10.1016/j.jse.2023.08.016)
  • [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. (10.1016/j.arthro.2016.07.004)
  • [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. (10.5397/cise.2019.22.2.59)
  • [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. (10.1177/0363546517703086)
  • [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. (10.1016/j.arthro.2019.12.006)
  • [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. (10.1177/03635465030310011101)
  • [L3] Patients with painful shoulders, irrespective of having type 2 diabetes mellitus, seem to have abnormal shoulder muscles. (10.1186/s12891-022-05627-9)
  • [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. (10.1016/j.jse.2016.04.030)
  • [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. (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. (10.1016/j.jse.2019.03.015)
  • [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. (10.1016/j.arthro.2018.01.044)
  • [Commentary] Early rotator cuff repair is beneficial for many patients with chronic but reparable rotator cuff tears, as it can reverse muscle atrophy and fatty infiltration. (10.1016/j.arthro.2021.07.006)
  • [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. (10.1016/j.jseint.2025.06.020)
  • [L4] Revision RCR improves clinical outcomes and shoulder function at midterm follow-up. (10.1177/0363546518786006)
  • [L4] Patch augmented cuff repair leads to a significant improvement of functional and structural outcomes. (10.1016/j.jse.2023.03.037)
  • [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. (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. (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. (10.1016/j.jse.2014.04.016)
  • [L3] Forty-seven (96 per cent) of the forty-nine shoulders had a good clinical result after distal release of the contracture. (10.2106/00004623-199802000-00010)
  • [L4] The supraspinatus and deltoid muscles are equally responsible for producing torque about the shoulder joint in the functional planes of motion. (10.2106/00004623-198668030-00013)
  • [Abstract] The muscle engages force in all ranges of four shoulder motions, and maximum ER in abduction is the reliable method to evaluate potential activity of the muscle. (10.1016/j.jse.2016.11.017)
  • [L5] The supraspinatus has a greater mechanical advantage versus the other tested muscles in the neutral arm position. (10.1016/j.jse.2008.10.021)
  • [L5] LTT may restore native glenohumeral kinematics more sufficiently than LDT, potentially leading to improved postoperative functional outcomes. (10.1016/j.jse.2022.05.003)
  • [Commentary] Compromise of the rotator cable does not induce functionally significant biomechanical impairment in an in vitro model, whereas tear extension involving all rotator cuff tissue above the geometric rotation center of the humeral head results in significant functional impairment. (10.1016/j.arthro.2021.04.029)
  • [L4] LDTT is an effective treatment for massive, irreparable posterosuperior rotator cuff tears and leads to substantial clinical improvement. (10.1016/j.jse.2007.02.128)
  • [L5] The study investigated whether supraspinatus and infraspinatus muscle subregions exhibit independent roles during forward flexion of the shoulder joint. (10.1016/j.jseint.2022.05.011)
  • [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. (10.2106/00004623-200006000-00012)
  • [L4] Future prospective studies will be necessary to understand the pathophysiology of rotator cuff disease as it relates to sex hormones. (10.2106/jbjs.21.00103)
  • [L5] The data from this biomechanical computer model supports the theory that by restoring the native joint line whilst performing an anatomical TSA, lower forces are required for the deltoid muscle to elevate the arm, compared to medializing the joint line. (10.1016/j.jse.2021.03.081)
  • [L5] The PPS injury produces alterations in GH kinematics with implications for GH joint instability, increased GH joint loading, and potential joint damage. (10.1016/j.jse.2024.12.023)
  • [L5] Inhibition or stimulation of muscle inflammation may be a potential target to enhance the outcome of the repaired torn rotator cuff. (10.1016/j.jse.2020.08.028)
  • [L5] LD transfer most closely approximates the native subscapularis regarding internal rotation moment arms. (10.1016/j.jse.2021.08.022)
  • [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. (10.1016/j.jse.2016.02.028)
  • [L3] B3 glenoids had a greater fatty infiltration of all rotator cuff muscles. (10.1177/17585732241269193)
  • [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. (10.1155/2021/7450000)
  • [Commentary] Modification of the Patte rotator cuff tear classification by using 2 coronal cuts to judge severity of retraction can help differentiate repairable from irreparable rotator cuff tears and allow for more accurate tear pattern identification. (10.1016/j.arthro.2020.08.027)
  • [L3] Radiological evaluation of the supraspinatus muscle alterations seemed to underestimate the degree of the same abnormalities evaluated at histology. (10.1186/s12891-023-06237-9)
  • [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. (10.1016/j.arthro.2025.01.019)
  • [L5] The subscapularis tendon is composed of 2 distinct fibrous layers, just like the supraspinatus tendon, but arranged differently. (10.1016/j.jse.2018.11.045)
  • [L5] Increased rotator cuff tendon signal on T2-weighted fat-suppressed MRI appears to be a marker of tendon degeneration and potentially of impaired healing potential, meriting closer attention when selecting chronic degenerative tears for repair. (10.1016/j.arthro.2024.09.041)
  • [L4] The study provides histological evidence for degeneration and fatty replacement of muscle tissue in chronically torn rotator cuff muscles. (10.1016/j.jse.2016.07.070)
  • [L5] In nonretracted cuff tears, fibrous tissue bound the tendon-to-bone junction with healing. (10.1016/j.arthro.2021.06.025)
  • [L4] This research provides evidence for the effective utilisation of artificial intelligence advancements for the automated measurement of the fatty infiltration of the RC muscles using shoulder MRI images. (10.1016/j.jisako.2025.100815)
  • [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. (10.1177/03635465231173697)
  • [L4] The authors suggest that patients with weakness in external rotation or abduction after posterior dislocation may have rotator cuff injury and that early MRI investigation is prudent for high-energy injuries. (10.1177/03635465030310060301)
  • [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. (10.1016/j.arthro.2012.02.026)
  • [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. (10.1016/j.jse.2022.01.030)

See Also

References

[1] Healing Rates of Massive Rotator Cuff Tears between Allograft Reconstruction vs. Maximal Repair: A Prospective Randomized Controlled Trial. Arthroscopy. 2019. DOI: 10.1016/j.arthro.2019.11.030

[2] Clinical and MRI Outcomes 10 Years After Repair of Massive Posterosuperior Rotator Cuff Tears. Journal of Bone and Joint Surgery. 2018. DOI: 10.2106/jbjs.17.01190

[3] The significance of subjective mechanical symptoms in rotator cuff pathology. Journal of Shoulder and Elbow Surgery. 2024. DOI: 10.1016/j.jse.2024.02.024

[4] Quantitative analysis of the rotator cuff muscles using three-dimensional magnetic resonance imaging. Journal of Shoulder and Elbow Surgery. 2017. DOI: 10.1016/j.jse.2016.11.032

[5] Long‐term outcome after arthroscopic rotator cuff treatment. Knee Surgery, Sports Traumatology, Arthroscopy. 2014. DOI: 10.1007/s00167-014-3234-8

[6] Long-Term Functional Outcome of Repair of Large and Massive Chronic Tears of the Rotator Cuff. The Journal of Bone & Joint Surgery*. 1999. DOI: 10.2106/00004623-199907000-00012

[7] Arthroscopic Rotator Cuff Repair: Is Healing Enough?. Journal of Shoulder and Elbow Surgery. 2021. DOI: 10.1016/j.jse.2021.03.112

[8] Latissimus Dorsi Tendon Transfer for Irreparable Posterosuperior Rotator Cuff Tears. Journal of Bone and Joint Surgery. 2007. DOI: 10.2106/jbjs.f.01160

[9] Editorial Commentary: A Bridge to Nowhere?…Do Patches Help Improve Our Outcomes After Rotator Cuff Surgery?. Arthroscopy. 2017. DOI: 10.1016/j.arthro.2017.01.007

[10] Factors Predicting Rotator Cuff Re-Tear: An Analysis of 1000 Consecutive Rotator Cuff Repairs. Journal of Shoulder and Elbow Surgery. 2013. DOI: 10.1016/j.jse.2013.07.021

[11] Response to Lievano regarding: “better functional outcomes and a lower infection rate can be expected after superior capsular reconstruction in comparison with latissimus dorsi tendon transfer for massive, irreparable posterosuperior rotator cuff tears: a systematic review”. Journal of Shoulder and Elbow Surgery. 2024. DOI: 10.1016/j.jse.2023.08.016

[12] Editorial Commentary: The Not So Benign Nature of an Isolated SLAP Repair. Arthroscopy. 2016. DOI: 10.1016/j.arthro.2016.07.004

[13] What Happens to Rotator Cuff Muscles after Rotator Cuff Repair?. Clinics in Shoulder and Elbow. 2019. DOI: 10.5397/cise.2019.22.2.59

[14] Proton Density Fat-Fraction of Rotator Cuff Muscles Is Associated With Isometric Strength 10 Years After Rotator Cuff Repair: A Quantitative Magnetic Resonance Imaging Study of the Shoulder. The American Journal of Sports Medicine. 2017. DOI: 10.1177/0363546517703086

[15] Adverse Impact of Corticosteroid Injection on Rotator Cuff Tendon Health and Repair: A Systematic Review. Arthroscopy. 2019. DOI: 10.1016/j.arthro.2019.12.006

[16] A Review of the Special Tests Associated with Shoulder Examination. The American Journal of Sports Medicine. 2003. DOI: 10.1177/03635465030310011101

[17] Shoulder muscle changes in patients with type 2 diabetes mellitus who have a painful shoulder: a quantitative muscle ultrasound study. BMC Musculoskeletal Disorders. 2022. DOI: 10.1186/s12891-022-05627-9

[18] 2013 Neer Award: predictors of failure of nonoperative treatment of chronic, symptomatic, full-thickness rotator cuff tears. Journal of Shoulder and Elbow Surgery. 2016. DOI: 10.1016/j.jse.2016.04.030

[19] The application of ultrasound elastography in the shoulder. Journal of Shoulder and Elbow Surgery. 2017. DOI: 10.1016/j.jse.2017.08.001

[20] Does strength deficit correlate with shoulder function in patients with rotator cuff tears? Characteristics of massive tears. Journal of Shoulder and Elbow Surgery. 2019. DOI: 10.1016/j.jse.2019.03.015

[21] Editorial Commentary: “Popeye” Deformity After Spontaneous Proximal Biceps Tendon Rupture: Image, Treat, or Ignore?. Arthroscopy. 2018. DOI: 10.1016/j.arthro.2018.01.044

[22] Editorial Commentary: Monitoring Tendon and Muscle Recovery After Rotator Cuff Repair Using Diagnostic Ultrasound Demonstrates that Early Repair is Beneficial for Many Patients With Reparable Tears. Arthroscopy: The Journal of Arthroscopic & Related Surgery. 2021. DOI: 10.1016/j.arthro.2021.07.006

[23] Trustworthy deep learning for the automated quantification of the fatty infiltration of the rotator cuff muscles using magnetic resonance imaging. JSES International. 2025. DOI: 10.1016/j.jseint.2025.06.020

[24] Clinical Outcomes, Tendon Integrity, and Shoulder Strength After Revision Rotator Cuff Reconstruction: A Minimum 2 Years’ Follow-up. The American Journal of Sports Medicine. 2018. DOI: 10.1177/0363546518786006

[25] Massive rotator cuff tears with short tendon length can be successfully repaired using synthetic patch augmentation. Journal of Shoulder and Elbow Surgery. 2023. DOI: 10.1016/j.jse.2023.03.037

[26] Editorial Commentary: In Situ Biceps Tenodesis Is Useful in the Treatment of Irreparable Rotator Cuff Tears. Arthroscopy. 2024. DOI: 10.1016/j.arthro.2024.09.019

[28] The influence of fatty infiltration and muscle atrophy of the rotator cuff muscles on midterm functional outcomes in total shoulder resurfacing at six years’ follow-up. Shoulder & Elbow. 2018. DOI: 10.1177/1758573218811655

[29] Chronic massive rotator cuff tear in rats: in vivo evaluation of muscle force and three-dimensional histologic analysis. Journal of Shoulder and Elbow Surgery. 2014. DOI: 10.1016/j.jse.2014.04.016

[30] Contracture of the Deltoid Muscle. The Journal of Bone and Joint Surgery (American Volume). 1998. DOI: 10.2106/00004623-199802000-00010

[31] Clarification of the role of the supraspinatus muscle in shoulder function.. The Journal of Bone & Joint Surgery. 1986. DOI: 10.2106/00004623-198668030-00013

[32] Anatomic study and electromyographic analysis of the teres minor muscle. Journal of Shoulder and Elbow Surgery. 2017. DOI: 10.1016/j.jse.2016.11.017

[33] Shoulder abduction moment arms in three clinically important positions. Journal of Shoulder and Elbow Surgery. 2009. DOI: 10.1016/j.jse.2008.10.021

[34] Biomechanical comparison of lower trapezius and latissimus dorsi transfer for irreparable posterosuperior rotator cuff tears using a dynamic shoulder model. Journal of Shoulder and Elbow Surgery. 2022. DOI: 10.1016/j.jse.2022.05.003

[35] Editorial Commentary: Rotator Cable Compromise May Not Always Result in Poor Shoulder Function. Arthroscopy: The Journal of Arthroscopic & Related Surgery. 2021. DOI: 10.1016/j.arthro.2021.04.029

[36] Teres minor integrity predicts outcome of latissimus dorsi tendon transfer for irreparable rotator cuff tears. Journal of Shoulder and Elbow Surgery. 2007. DOI: 10.1016/j.jse.2007.02.128

[37] The functional role of the supraspinatus and infraspinatus muscle subregions during forward flexion: a shear wave elastography study. JSES International. 2022. DOI: 10.1016/j.jseint.2022.05.011

[38] Dynamic Glenohumeral Stability Provided by the Rotator Cuff Muscles in the Mid-Range and End-Range of Motion. The Journal of Bone and Joint Surgery-American Volume. 2000. DOI: 10.2106/00004623-200006000-00012

[39] The Effect of Sex Hormone Deficiency on the Incidence of Rotator Cuff Repair. Journal of Bone and Joint Surgery. 2022. DOI: 10.2106/jbjs.21.00103

[40] Joint-Line Medialization Following Anatomical Total Shoulder Replacement Requires More Rotator Cuff Activity to Preserve Joint Stability. Journal of Shoulder and Elbow Surgery. 2021. DOI: 10.1016/j.jse.2021.03.081

[41] Pectoralis Major Muscle: Function of Sternal Portion and Mechanism of Rupture of Normal Muscle: Case Reports.. The Journal of Bone and Joint Surgery. American Volume. 1961.

[42] 2025 Basic Science Neer Award Winner: The impact of posterior and posterior superior labral injuries and the effect of their treatment on glenohumeral kinematics in the deceleration and follow-through phase of throwing: a biomechanical study. Journal of Shoulder and Elbow Surgery. 2025. DOI: 10.1016/j.jse.2024.12.023

[43] The inflammatory response of the supraspinatus muscle in rotator cuff tear conditions. Journal of Shoulder and Elbow Surgery. 2021. DOI: 10.1016/j.jse.2020.08.028

[44] Biomechanical analysis of latissimus dorsi, pectoralis major, and pectoralis minor transfers in subscapularis-deficient shoulders. Journal of Shoulder and Elbow Surgery. 2022. DOI: 10.1016/j.jse.2021.08.022

[45] The rotator cuff muscles are antagonists after reverse total shoulder arthroplasty. Journal of Shoulder and Elbow Surgery. 2016. DOI: 10.1016/j.jse.2016.02.028

[46] The association of rotator cuff muscle morphology and glenoid morphology in primary glenohumeral osteoarthritis. Shoulder & Elbow. 2024. DOI: 10.1177/17585732241269193

[47] The Subscapularis Muscle: A Proposed Classification System. BioMed Research International. 2021. DOI: 10.1155/2021/7450000

[48] Editorial Commentary: Look More Closely at those Coronal Magnetic Resonance Imaging Cuts Before Concluding a Rotator Cuff Tendon Tear Is Irreparable—Don’t Let an L-Shaped Tear Fool You. Arthroscopy: The Journal of Arthroscopic & Related Surgery. 2020. DOI: 10.1016/j.arthro.2020.08.027

[49] Histological, radiological and clinical analysis of the supraspinatus tendon and muscle in rotator cuff tears. BMC Musculoskeletal Disorders. 2023. DOI: 10.1186/s12891-023-06237-9

[50] Editorial Commentary : Prospective Study Is Required to Determine If Preoperative Statin Dosing Is Associated With Increased Rates of Retear After Arthroscopic Rotator Cuff Repair. Arthroscopy. 2025. DOI: 10.1016/j.arthro.2025.01.019

[51] Histologic characteristics of the subscapularis tendon from muscle to bone: reference to subscapularis lesions. Journal of Shoulder and Elbow Surgery. 2019. DOI: 10.1016/j.jse.2018.11.045

[52] Editorial Commentary: Magnetic Resonance Imaging Reveals Rotator Cuff Tear Size, Retraction, Length, and Geometry; Muscle Volume and Degeneration; and Tendon Quality. Arthroscopy. 2024. DOI: 10.1016/j.arthro.2024.09.041

[53] Histological quantification of chronic human rotator cuff muscle degeneration. Journal of Shoulder and Elbow Surgery. 2016. DOI: 10.1016/j.jse.2016.07.070

[56] Retracted Rotator Cuff Repairs Heal With Disorganized Fibrogenesis Without Affecting Biomechanical Properties: A Comparative Animal Model Study. Arthroscopy. 2021. DOI: 10.1016/j.arthro.2021.06.025

[57] Trustworthy Deep Learning for the Automated Quantification of Fatty Infiltration of the Rotator Cuff Muscles Using MRI. Journal of ISAKOS. 2025. DOI: 10.1016/j.jisako.2025.100815

[58] Association Between Supraspinatus Tendon Retraction, Histologic Myofiber Size, and Supraspinatus Muscle Atrophy on MRI. The American Journal of Sports Medicine. 2023. DOI: 10.1177/03635465231173697

[59] Traumatic Posterior Dislocation of the Shoulder Associated with a Massive Rotator Cuff Tear. The American Journal of Sports Medicine. 2003. DOI: 10.1177/03635465030310060301

[60] Functional Outcome After Arthroscopic Repair of Massive Rotator Cuff Tears in Individuals With Pseudoparalysis. Arthroscopy. 2012. DOI: 10.1016/j.arthro.2012.02.026

[61] Deep Learning Provides A Reliable Automatic Quantification Of Rotator Cuff Muscle Degeneration Derived From Preoperative Arthroplasty Planification Shoulder CT Images. Journal of Shoulder and Elbow Surgery. 2022. DOI: 10.1016/j.jse.2022.01.030

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