Rotator Cuff Fatty Infiltration Research Articles

The Use of Dixon Magnetic Resonance Imaging Methods for the Quantification of Rotator Cuff Fatty Infiltration: A Systematic Review

Fatty infiltration of the rotator cuff muscles is very common following rotator cuff tears and is one of the most important factors in determining treatment. Current clinical practice relies on subjective evaluation of fatty infiltration through categorical scoring based on the Goutallier classification system. The Dixon magnetic resonance imaging (MRI) sequence provides flexibility in selecting echo times for water–fat separation. The Dixon method, therefore, has the potential to provide robust and high-quality fat quantification that allows for more accurate calculation of fat fraction (%Fat) of the rotator cuff muscles than the Goutallier classification system. However, significant variance exists in sequencing and post-processing methodology within the recent application of Dixon sequences to quantify rotator cuff fatty infiltration. In this paper, we conducted a systematic review to synthesize the relevant literature utilizing Dixon sequencing for the quantification of rotator cuff fatty infiltration. The literature search was extracted from 1094 articles, with 12 studies included in the final review. Regardless of the varying sequencing pattern and post-processing techniques among studies, the findings suggest the Dixon method is reliable for quantitatively calculating the fat fraction of the rotator cuff muscles, even at very low levels of fatty infiltration. In addition, a quantitative difference in fat fraction was observed between participants with different degrees of tear vs. those without any shoulder pathologies. Multi-point Dixon imaging has the potential to be utilized clinically to objectively quantify fatty infiltration and may lead to improved clinical decision making for patients with rotator cuff tears.

Investigating the relationship between quantitative-based ultrasound and MRI estimations of rotator cuff fatty infiltration.

Fatty infiltration (FI) of the rotator cuff has important clinical implications. Quantitatively estimating FI using ultrasound (US) has considerable benefits for assessing FI in a non-invasive, accessible manner. This research investigated whether FI of the supraspinatus (SS) and infraspinatus (IS), estimated using US was related to intramuscular fat fractions measured from magnetic resonance images (MRI). Data from 12 healthy young adult participants were used for analysis. US images of the SS and IS were captured using multiple transducer placement techniques from which echogenicity of the muscle region was quantified. Shoulder MRI were captured from which SS and IS were manually segmented and intramuscular fat fractions calculated. Six upper limb strength exertions were performed, resisted by a hand dynamometer. IS and SS echogenicity explained a significant amount of variance in MRI fat fractions for certain body positions and transducer techniques. Echogenicity agreement was higher for IS than SS. Significant relationships were identified between strength exertions and both echogenicity and MRI muscle volume, but not MRI fat fraction. This research provides preliminary evidence showing that quantitative-based US methods can be used to estimate MRI calculated fat fractions for the rotator cuff.

Serial 3D CT analysis of humeral head alignment in relation to glenoid correction and outcomes after total shoulder arthroplasty

Posterior humeral head (HH) subluxation after anatomic total shoulder arthroplasty (aTSA) is associated with worse outcomes, but it is unclear how corrective glenoid reaming correlates with HH alignment and whether HH alignment changes over time. Therefore, it was aimed to analyze the relationship between HH alignment and the scapula following aTSA to identify anatomic andsurgical factors that contribute to realignment of the HH, glenoid loosening, and clinical outcomes. Three-dimensional scapulohumeral alignment was assessed on three-dimensionally reconstructed computed tomography scans of 23 patients: preoperative (T0), 2 years post-aTSA (T1), and ≥5 years post-aTSA (T2). Anterior-posterior (AP), superior-inferior (SI), and medial-lateral offset measures of the HH center to the scapula were referenced to the HH diameter (scapulohumeral subluxation index). Glenoid version and inclination were measured at T0 and T1. Central peg osteolysis, rotator cuff fatty infiltration, and vault perforation were assessed on two-dimensional computed tomography. Relative Constant Score at T2 measured clinical outcome. Glenoid correction correlated strongly with AP and SI position of the HH (r=0.733 and r=0.797, respectively). Each degree of retroversion correction resulted in 0.9% AP scapulohumeral subluxation index offset change toward anterior. Each degree of inclination correction to superior resulted in a 1.0% offset change toward superior. A gradual postoperative proximal (mean difference [MD],-3%; P=.019), anterior (MD, 2%; P=.025), and medial (MD, 3 mm; P<.001) HH migration was observed. Asymmetric progressive rotator cuff fatty infiltration was associated with the direction of change in AP alignment over time (odds ratio, 2.04; P=.046), with progressive subscapularis fatty infiltration as the primary factor associated with gradual anterior HH translation (odds ratio, 15.61; P=.028). Gradual HH medialization was an indicator of glenoid components at risk for loosening (difference between medians, 4 mm; P=.003). Osteolysis around the central glenoid peg was influenced by overcorrection of glenoid version (MD, 7°; P=.038). Preoperative glenoid inclination was the sole anatomical or surgical factor predicting clinical outcome, as larger inferior inclination at T0 was associated with worse relative Constant Score at T2 (P=.016). Corrective glenoid reaming was an effective surgical technique to correct HH alignment in the AP and SI direction. Gradual anterior HH translation after aTSA was associated with progressive subscapularis fatty infiltration, and substantial HH medialization was an important indicator for potential glenoid loosening. While postoperative glenoid version and AP HH alignment were important for radiographic outcome, preoperative glenoid inclination predicted clinical outcome, as larger preoperative inferior inclination resulted in worse clinical scores.

Extension of the shoulder is essential for functional internal rotation after reverse total shoulder arthroplasty.

Disabling loss of functional internal rotation (fIR) after reverse total shoulder arthroplasty (RTSA) is frequent but not well understood. This study tested the hypothesis that limitation of fIR after RTSA is not primarily related to a deficit in internal rotation. Fifty patients (mean age at RTSA, 74±11.7 years) who were consecutively seen at a yearly follow-up visit at 1-10 years (median, 4 years) after RTSA were prospectively examined with special attention to fIR. Patients with axillary nerve or deltoid dysfunction were excluded. Relative (age- and sex-adjusted) Constant-Murley scores (CSs) and Subjective Shoulder Values were assessed preoperatively and at final follow-up. In addition, active extension and 4 postoperative activities of daily living (ADLs) requiring fIR were tested at follow-up. Rotator cuff fatty infiltration and notching were evaluated radiographically. For analysis, patients were divided into a group with poor fIR (fIR-, n=19), defined as ≤2 internal-rotation points in the CS, and a group with good fIR (fIR+, n=31), defined as ≥4 internal-rotation points in the CS. Active extension of the contralateral shoulders was comparable in the fIR- group (mean, 60.3° [standard deviation (SD), 11.2°]) and fIR+ group (66.1° [SD, 14.2°]). Postoperatively, a difference in active extension between the unaffected and operated sides was present in both groups and averaged 16° (55° [SD, 14.3°] in fIR+ group and 39.1° [SD, 10.8°] in fIR- group; P<.001). No patient in the fIR+group had active extension < 40° (range, 40°-85°). Shoulders with extension ≥ 40° but unsatisfactory fIR had restricted passive internal rotation in extension. The ability to perform ADLs behind the back correlated better with shoulder extension than with so-called fIR measurements in the CS. Functional internal rotation after RTSA requires at least 40° of shoulder extension. If fIR is unsatisfactory despite 40° of extension, passive restriction of internal rotation in full extension is the limiting factor. It is crucial to preserve or restore active shoulder extension to allow ADLs involving internal rotation.

Coracoid Impingement and Morphology Is Associated with Fatty Infiltration and Rotator Cuff Tears.

This study describes measurements between the coracoid, glenoid, and humerus; characterizes coracoid shape, rotator cuff fatty infiltration, and quantitatively evaluates coracoid impingement and its association with anterosuperior rotator cuff tears (ASCT). 193 shoulder magnetic resonance imaging (MRI) scans demonstrating: rotator cuff tear; isolated tear of the supraspinatus; tear of supraspinatus and subscapularis, were included. MRI measurements included coracohumeral interval (CHI), coracoid overlap (CO), coracoid recess (CR), coracoglenoid angle (CGA), and coracoglenoid interval (CGI) on axial slices; acromiohumeral interval (AHI) on coronal slices; and coracohumeral interval (CHI) and coracoacromial ligament (CAL) thickness on sagittal slices. The coracoid shape was classified as flat, curved, or hooked. An Independent T-test was used to compare the MRI measurements and the different rotator cuff tear groups. In 79% of the patients with ASCT tears, the coracoid was curved. Axial CHI, CGA, sagittal CHI, and AHI were decreased in ASCT when compared to no tears and isolated supraspinatus tears (p < 0.05). CO was increased in ASCT compared to no tears and isolated supraspinatus tears (p < 0.05). Patients with an ASCT had a significantly increased subscapularis and supraspinatus Goutallier fatty infiltration score when compared to no tear and isolated supraspinatus tears (p < 0.05). These quantitative measurements may be useful in identifying patients at risk for ASCT. Level of Evidence III.

Rotator cuff fatty infiltration and muscle atrophy: relation to glenoid deformity in primary glenohumeral osteoarthritis.

Muscle atrophy (MA) and fatty infiltration (FI) are degenerative processes of the rotator cuff musculature that have incompletely understood relationships with the development of eccentric glenoid wear in the setting of primary glenohumeral osteoarthritis (GHOA). All patients with GHOA and an intact rotator cuff who underwent both magnetic resonance imaging and computed tomography scans of the affected shoulder prior to total shoulder arthroplasty between 2015 and 2020 were identified from a prospectively maintained registry. Rotator cuff MA was measured quantitatively on sequential sagittal magnetic resonance images, whereas FI was assessed on sagittal magnetic resonance imaging slices using the Goutallier classification. Preoperative computed tomography scans were reconstructed using automated 3-dimensional software to determine glenoid retroversion, glenoid inclination, and humeral head subluxation. Glenoid deformity was classified according to the Walch classification. Univariate and multivariable regression analyses were performed to characterize associations between age, sex, muscle area, FI, and glenoid morphology. Among the 127 included patients, significant associations were found between male sex and larger overall rotator cuff musculature (P < .01), increased ratio of the posterior rotator cuff (PRC) to the subscapularis area (P = .01), and glenoid retroversion (19° vs. 14°, P< .01). Larger supraspinatus and PRC muscle size was correlated with increased retroversion (r = 0.23 [P = .006] for supraspinatus and r= 0.25 [P=.004] for PRC) and humeral head subluxation (r = 0.25 [P = .004] for supraspinatus and r = 0.28 [P = .001] for PRC). The ratio of PRC muscle size to anterior rotator cuff muscle size was not associated with evidence of eccentric glenoid wear (P > .05). After we controlled for confounding factors, increasing glenoid retroversion was associated with high-grade infraspinatus FI (β, 6.8; 95% confidence interval, 2.9-10.7; P < .01) whereas larger PRC musculature was predictive of a Walch type B (vs. type A) glenoid (odds ratio, 1.3; 95% confidence interval, 1.0-1.5; P = .04). Patients with eccentric glenoid wear in the setting of primary GHOA and an intact rotator cuff appear to have both larger PRC musculature and higher rates of infraspinatus FI. Although the temporal and causal relationships of these associations remain ambiguous, MA and FI should be considered 2 discrete processes in the natural history of GHOA.

Three-dimensional muscle loss assessment: a novel computed tomography–based quantitative method to evaluate rotator cuff muscle fatty infiltration

Rotator cuff fatty infiltration (FI) is one of the most important parameters to predict the outcome of certain shoulder conditions. The primary objective of this study was to define a new computed tomography (CT)-based quantitative 3-dimensional (3D) measure of muscle loss (3DML) based on the rationale of the 2-dimensional (2D) qualitative Goutallier score. The secondary objective of this study was to compare this new measurement method to traditional 2D qualitative assessment of FI according to Goutallier etal and to a 3D quantitative measurement of fatty infiltration (3DFI). 102 CT scans from healthy shoulders (46) and shoulders with cuff tear arthropathy (21), irreparable rotator cuff tears (18), and primary osteoarthritis (17) were analyzed by 3 experienced shoulder surgeons for subjective grading of fatty infiltration according to Goutallier, and their rotator cuff muscles were manually segmented. Quantitative 3D measurements of fatty infiltration (3DFI) were completed. The volume of muscle fibers without intramuscular fat was then calculated for each rotator cuff muscle and normalized to the patient's scapular volume to account for the effect of body size (NVfibers). 3D muscle mass (3DMM) was calculated by dividing the NVfibers value of a given muscle by the mean expected volume in healthy shoulders. 3D muscle loss (3DML) was defined as 1 - (3DMM). The correlation between Goutallier grading, 3DFI, and 3DML was compared using a Spearman rank correlation. Interobserver reliability for the traditional 2D Goutallier grading was moderate for the infraspinatus (ISP, 0.42) and fair for the supraspinatus (SSP, 0.38), subscapularis (SSC, 0.27) and teres minor (TM, 0.27). 2D Goutallier grading was found to be significantly and highly correlated with 3DFI (SSP, 0.79; ISP, 0.83; SSC, 0.69; TM, 0.45) and 3DML (SSP, 0.87; ISP, 0.85; SSC, 0.69; TM, 0.46) for all 4 rotator cuff muscles (P < .0001). This correlation was significantly higher for 3DML than for the 3DFI for SSP only (P = .01). The mean values of 3DFI and 3DML were 0.9% and 5.3% for Goutallier 0, 2.9% and 25.6% for Goutallier 1, 11.4% and 49.5% for Goutallier 2, 20.7% and 59.7% for Goutallier 3, and 29.3% and 70.2% for Goutallier 4, respectively. The Goutallier score has been helping surgeons by using 2D CT scan slices. However, this grading is associated with suboptimal interobserver agreement. The new measures we propose provide a more consistent assessment that correlates well with Goutallier's principles. As 3DML measurements incorporate atrophy and fatty infiltration, they could become a very reliable index for assessing shoulder muscle function. Future algorithms capable of automatically calculating the 3DML of the cuff could help in the decision process for cuff repair and the choice of anatomic or reverse shoulder arthroplasty.

CORR Insights®: Imbalance in Axial-plane Rotator Cuff Fatty Infiltration in Posteriorly Worn Glenoids in Primary Glenohumeral Osteoarthritis: An MRI-based Study.

CORR Insights®: Imbalance in Axial-plane Rotator Cuff Fatty Infiltration in Posteriorly Worn Glenoids in Primary Glenohumeral Osteoarthritis: An MRI-based Study.

Imbalance in Axial-plane Rotator Cuff Fatty Infiltration in Posteriorly Worn Glenoids in Primary Glenohumeral Osteoarthritis: An MRI-based Study.

Imbalance in Axial-plane Rotator Cuff Fatty Infiltration in Posteriorly Worn Glenoids in Primary Glenohumeral Osteoarthritis: An MRI-based Study.

Atrophy patterns in isolated subscapularis lesions

BackgroundWhile supraspinatus atrophy can be described according to the system of Zanetti or Thomazeau there is still a lack of characterization of isolated subscapularis muscle atrophy. The aim of this study was to describe patterns of muscle atrophy following repair of isolated subscapularis (SSC) tendon.MethodsForty-nine control shoulder MRI scans, without rotator cuff pathology, atrophy or fatty infiltration, were prospectively evaluated and subscapularis diameters as well as cross sectional areas (complete and upper half) were assessed in a standardized oblique sagittal plane. Calculation of the ratio between the upper half of the cross sectional area (CSA) and the total CSA was performed. Eleven MRI scans of patients with subscapularis atrophy following isolated subscapularis tendon tears were analysed and cross sectional area ratio (upper half /total) determined. To guarantee reliable measurement of the CSA and its ratio, bony landmarks were also defined.All parameters were statistically compared for inter-rater reliability, reproducibility and capacity to quantify subscapularis atrophy.ResultsThe mean age in the control group was 49.7 years (± 15.0).The mean cross sectional area (CSA) was 2367.0 mm2 (± 741.4) for the complete subscapularis muscle and 1048.2 mm2 (± 313.3) for the upper half, giving a mean ratio of 0.446 (± 0.046).In the subscapularis repair group the mean age was 56.7 years (± 9.3). With a mean cross sectional area of 1554.7 mm2 (± 419.9) for the complete and of 422.9 mm2 (± 173.6) for the upper half of the subscapularis muscle, giving a mean CSA ratio of 0.269 (± 0.065) which was seen to be significantly lower than that of the control group (p < 0.05).ConclusionAnalysis of typical atrophy patterns of the subscapularis muscle demonstrates that the CSA ratio represents a reliable and reproducible assessment tool in quantifying subscapularis atrophy. We propose the classification of subscapularis atrophy as Stage I (mild atrophy) in case of reduction of the cross sectional area ratio < 0.4, Stage II (moderate atrophy) in case of < 0.35 and Stage III (severe atrophy) if < 0.3.

Rotator cuff fatty infiltration and muscle atrophy do not impact clinical outcomes after reverse total shoulder arthroplasty for glenohumeral osteoarthritis with intact rotator cuff.

The clinical significance of rotator cuff muscle quality following reverse total shoulder arthroplasty (RTSA) remains uncertain. The purpose of this study was to evaluate the influence of rotator cuff fatty infiltration (FI) and muscle atrophy (MA) on clinical outcomes following RTSA for glenohumeral osteoarthritis (GHOA). One hundred eight shoulders with primary GHOA that underwent RTSA with a lateralized glenosphere for GHOA with a minimum of 2-year follow-up were identified from a prospectively maintained registry. Each rotator cuff muscle was assessed on preoperative magnetic resonance imaging for FI and quantitative amount of MA. Pre- and postoperative outcomes included American Shoulder and Elbow Surgeons Standardized Shoulder Assessment Form score, Single Assessment Numerical Evaluation (SANE) score, visual analog scale pain score, and range of motion (ROM) measurements. Eighty-one patients with a mean age of 70.7 ± 5.4 years (range: 57-85) were included who underwent RTSA with a mean follow-up of 2.1 years (range: 2-3.9 years). There was a significant improvement in all outcome measures postoperatively (P < .01). Twenty-two patients (27.1%) had moderate to severe combined infraspinatus and teres minor FI. There was no significant difference in the postoperative external rotation or clinical outcomes compared with those patients with only mild FI (P > .05). Forty-three patients (53.1%) had moderate to severe global rotator cuff FI. There was no significant difference in postoperative outcomes compared with those patients with only mild FI (P < .01). Univariate analysis did not reveal any significant association between the degree of FI or MA of any individual rotator cuff muscle and postoperative clinical outcomes or ROM. The size ratio of the posterior rotator cuff to the subscapularis muscle was positively correlated with preoperative SANE scores but negatively correlated with absolute postoperative and change in preoperative to postoperative SANE scores. However, there were no significant correlations between this size ratio and the other outcome measures. Rotator cuff muscle quality as assessed by MA and FI does not impact clinical outcomes following RTSA with a lateralized glenosphere in patients with GHOA and an intact rotator cuff.

How to Measure Glenoid Bone Stock and Version and Why It Is Important: A Practical Guide

Shoulder osteoarthritis (OA) is a common and debilitating condition and a source of high morbidity and medical expenditures across the world among individuals older than 60 years. Shoulder OA results in the gradual destruction of articular cartilage of the humeral head and glenoid component, causing inflammation, pain, and a restricted range of motion. Most patients are diagnosed with shoulder OA after experiencing shoulder pain and stiffness, and the diagnosis is often made after medical and physical histories are obtained and physical and imaging examinations are performed. Use of various surgical techniques such as total anatomic or reverse shoulder arthroplasty and hemiarthroplasty has increased in recent years, resulting in reduced morbidity and improved functional status of patients. However, the rate of surgical complications such as premature loosening of components is significant, reducing the effectiveness of such procedures. Data in the literature indicate that high-grade fatty infiltration of the rotator cuff muscle before surgery is associated with postoperative glenoid component loosening. High-grade rotator cuff fatty infiltration and atrophy have been found to be associated with more severe Walch classification-based glenoid morphology subtypes, increased joint line medialization, glenoid bone loss, and increased pathologic glenoid version. The authors describe how advanced imaging techniques are used for preoperative evaluation of the shoulder and discuss how to measure glenoid version and bone stock and classify glenoid morphology types on the basis of Walch classification, as these parameters are commonly used in surgical planning. Methods involving the use of Friedman and paleoglenoid lines for respective measurements are illustrated by using three-dimensional CT and MRI case examples. ©RSNA, 2020.

β3-Adrenergic receptor agonist treats rotator cuff fatty infiltration by activating beige fat in mice

Rotator cuff (RC) muscle atrophy and fatty infiltration (FI) are independent factors correlated with failure of attempted tendon repair in larger RC tears. However, there is no effective treatment for RC muscle atrophy and FI at this time. The recent discovery of beige adipose tissue (BAT) in adults shed light on a new avenue in treating obesity and excessive fat deposition by promoting BAT activity. The goal of this study was to define the role of intramuscular BAT in RC muscle FI and the effect of β3-adrenergic receptor agonists in treating RC muscle FI by promoting BAT activity. Three-month-old wild-type C57BL/6J, platelet derived growth factor receptor-alpha (PDGFRα) green fluorescent protein (GFP) reporter and uncoupling protein 1 (UCP-1) knockout mice underwent a unilateral RC injury procedure, which included supraspinatus (SS) and infraspinatus tendon resection and suprascapular nerve transection. To stimulate BAT activity, amibegron, a selective β3-adrenergic receptor agonist, was administered to C57BL/6J mice either on the same day as surgery or 6 weeks after surgery through daily intraperitoneal injections. Gait analysis was conducted to measure forelimb function at 6 weeks or 12 weeks (in groups receiving delayed amibegron treatment) after surgery. Animals were killed humanely at 6 weeks (or 12 weeks for delayed amibegron groups) after surgery. SS muscles were harvested and analyzed histologically and biochemically. Histologicanalysis of SS muscles from PDGFRα-GFP reporter mice showed that PDGFRα-positive fibroadipogenic progenitors in RC muscle expressed UCP-1, a hallmark of BAT during the development of FI after RC tears. Impairing BAT activity by knocking out UCP-1 resulted in more severe muscle atrophy and FI with inferior forelimb function in UCP-1 knockout mice compared with wild-type mice. Promoting BAT activity with amibegron significantly reduced muscle atrophy and FI after RC tears and improved forelimb function. Delayed treatment with amibegron reversed muscle atrophy and FI in muscle. Fat accumulated in muscle after RC tears possesses BAT characteristics. Impairing BAT activity results in worse RC muscle atrophy and FI. Amibegron reduces and reverses RC atrophy and FI by promoting BAT activity.

Modified L'Episcopo tendon transfer for isolated loss of active external rotation

Patients with isolated loss of active external rotation (ILER) but preserved active forward elevation have recently been identified as a rare and distinct clinical entity. The modified L'Episcopo procedure attempts to restore horizontal muscle balance and restore active external rotation. A retrospective study was performed for all patients with ILER and preserved forward elevation with Hamada stage ≤2 changes undergoing the modified L'Episcopo tendon transfer. Preoperative rotator cuff fatty infiltration and morphology was reported. Clinical, radiographic, and functional outcomes were recorded preoperatively and compared to postoperative outcomes at a minimum of 24 months' follow-up. Nine patients (8 male, 1 female) with a mean age of 58.4 years(range, 51-67 years) were evaluated at a mean follow-up of 64.3 months (range, 24-126 months). Significant improvement was demonstrated in active external rotation with the arm at the side (mean increase of 47°; range, 30°-60°, P = .004) and at 90° abduction(mean increase of 41°; range, 20°-70°, P = .004). The mean Constant score and pain score significantly improved at final follow-up (P = .004). All patients were either very satisfied or satisfied, with a mean subjective shoulder value of 74% (range, 60%-99%). In appropriately selected patients with ILER and preserved active forward elevation, the modified L'Episcopo procedure can restore horizontal muscle balance and produce significant improvements in active external rotation, Constant score, and pain.

Do Outcomes of Arthroscopic Subscapularis Tendon Repairs Depend on Rotator Cuff Fatty Infiltration?

Background:Rotator cuff fatty infiltration has been correlated with poorer radiographic and clinical outcomes in supraspinatus and infraspinatus tendon repairs, but this has not been well-studied in subscapularis tendon repairs.Purpose:To evaluate the influence of preoperative rotator cuff fatty infiltration on postoperative outcomes for patients undergoing arthroscopic subscapularis tendon repair.Study Design:Cohort study; Level of evidence, 3.Methods:Patients who underwent arthroscopic subscapularis repair between 2010 and 2016 were retrospectively identified, and demographic data and surgical findings were recorded. The extent of fatty infiltration was determined on preoperative magnetic resonance imaging by the Fuchs modification of the Goutallier classification. At the most recent follow-up, patients completed the Patient-Reported Outcomes Measurement Information System for Upper Extremity (PROMIS-UE) computer adaptive test and a postoperative visual analog scale for pain. The distribution of fatty infiltration was compared between patients undergoing subscapularis tendon repair versus subscapularis tendon repair combined with a posterior cuff repair. Outcomes were compared for patients using Goutallier grade 0-1 versus grade ≥2 changes in each rotator cuff muscle. Multivariate linear regression analysis was performed to evaluate the influence of muscle quality, as well as demographic factors, on PROMIS-UE scores. Significance was defined as P < .05.Results:There were 140 shoulders included (mean age, 61.8 years; 42.1% female; mean follow-up, 51.7 months). The prevalence of Goutallier grade 2 changes or higher was significantly greater in patients with multitendon repair relative to isolated subscapularis tendon repair. For the overall group of all patients undergoing subscapularis tendon repair, whether in isolation or as part of a multitendon repair, PROMIS-UE scores were significantly lower for patients with infraspinatus muscle grade 2 or higher Goutallier changes relative to grade 0 or 1. After adjustment for age, body mass index, patient sex, and fatty infiltration in other rotator cuff muscles, poor infraspinatus muscle quality remained the only significant predictor for lower PROMIS-UE scores.Conclusion:Patients undergoing arthroscopic subscapularis tendon repair with poor infraspinatus muscle quality had worse patient-reported outcomes. This was true whether subscapularis tendon repair was isolated or was performed in conjunction with supraspinatus and infraspinatus tendon repairs.

Pre-operative factors affecting the indications for anatomical and reverse total shoulder arthroplasty in primary osteoarthritis and outcome comparison in patients aged seventy years and older.

We evaluated the pre-operative factors affecting anatomical and reverse total shoulder arthroplasty (TSA and RTSA) indications in primary osteoarthritis and compared outcomes in patients aged 70years and older. Fifty-eight patients received a TSA with an all-polyethylene glenoid component (APGC) or an RTSA with/without glenoid lateralization and the same curved short-stem humeral component. Active anterior and lateral elevation (AAE, ALE), internal and external rotation (IR, ER), pain, and the Constant-Murley score (CS) were recorded pre and post-operatively. Pre-operative rotator cuff (RC) fatty infiltration (FI) and modified Walch glenoid morphology were assessed. Humeral and glenoid component radiological outcomes were recorded. RTSA were older than TSA patients (p = 0.006), had lower pre-operative AAE (p < 0.001), ALE (p< 0.001), IR (p = 0.002), pain (p = 0.008) and CS (p < 0.001), and greater supraspinatus FI (p < 0.001). At a mean of 28.8months, both implants yielded significantly different post-operative scores and similar complication rates. Both groups achieved similar post-operative AAE, ER, and IR; ALE was higher in TSA (p = 0.006); and AAE and ALE delta scores were higher in RTSA (p = 0.045 and p = 0.033, respectively). Radiolucent line rates were higher around the TSA APGC than the RTSA baseplate (p = 0.001). High-grade RC FI adversely affected mobility improvement. Humeral cortical thinning was significantly higher in TSA (p = 0.001). RTSA patients were older, had poorer pre-operative active mobility, and had greater RC FI than TSA. Both devices provided good mid-term clinical and ROM improvement.

Type E2 glenoid bone loss orientation and management with augmented implants

The purpose of this study was 2-fold: (1) to quantify type E2 bone loss orientation and its association with rotator cuff fatty infiltration and (2) to examine reverse baseplate designs used to manage type E2 glenoids. Computed tomography scans of 40 patients with type E2 glenoids were examined for pathoanatomic features and erosion orientation. The rotator cuff fatty infiltration grade was compared with the erosion orientation angle. To compare reconstructive options in light of the pathoanatomic findings, virtual implantation of 4 glenoid baseplate designs (standard, half wedge, full wedge, and patient-matched) was conducted to determine the volume of bone removal for seating and impingement-free range of motion. The mean type E2 erosion orientation angle was 47° ± 17° from the 0° superoinferior glenoid axis, resulting in the average erosion being located in the posterosuperior quadrant directed towardthe 10:30 clock-face position. The type E2 neoglenoid, on average, involved 67% of the total glenoid surface (total surface area, 946 ± 209 mm2; neoglenoid surface area, 636 ± 247 mm2). The patient-matched baseplate design resulted in significantly (P ≤ .01) less bone removal (200 ± 297 mm3) for implantation, followed by the full-wedge design (1228 ± 753 mm3), half-wedge design (1763 ± 969 mm3), and standard (non-augmented) design (4009 ± 1210 mm3). We noted a marked difference in erosion orientation towarda more superior direction as the subscapularis fatty infiltration grade increased from grade 3 to grade 4 (P < .001). The average type E2 erosion orientation was directed towardthe 10:30 clock-face position in the posterosuperior glenoid quadrant. This orientation resulted in the patient-matched glenoid augmentation requiring the least amount of bone removal for seating, followed by the full-wedge, half-wedge, and standard designs. Implant selection also substantially affected computationally derived range of motion in external rotation, flexion, extension, and adduction.

Qualitative and quantitative analysis of glenoid bone stock and glenoid version: inter-reader analysis and correlation with rotator cuff tendinopathy and atrophy in patients with shoulder osteoarthritis.

Glenoid bone stock and morphology and rotator cuff muscle quality and tendon integrity affect the outcome of total shoulder arthroplasty. We hypothesized that glenoid bone loss correlates with rotator cuff muscle fatty infiltration (FI), tendinopathy, and atrophy. Forty-three 3D CT scans and MRIs of 43 patients (mean age 62years; SD 13years; range 22-77years) referred for primary shoulder pain were evaluated. Measurements of glenoid bone stock, version, and posterior humeral subluxation index (HSI) were assessed on an axial CT image reconstructed in the true scapular plane. Measurements utilized the Friedman line to approximate the pre-pathologic surface. Glenoid morphology was assigned by modified Walch classification. Rotator cuff FI, atrophy, and tendon integrity were assessed on corresponding MRIs. There was a very strong negative correlation between increasing glenoid version and HSI (r= - 0.908; p< 0.0001). There was a moderately negative correlation between anterior bone loss and HSI (r= - 0.562; p< 0.0001) and a moderately positive correlation between posterior bone loss and HSI (r= 0.555; p< 0.0001). Subscapularis muscle FI correlated moderately with increased anterior and central bone loss and increased humeral head medialization (r= 0.512, p= 0.0294; r= 0.479, p= 0.033; r= 0.494, p= 0.0294; respectively). Inter-observer reliability (intra-class correlation coefficient [ICC] and kappa) was good to excellent for all measurements and grading. Glenoid anteversion and anterior and posterior bone loss are associated with varying HSI. Subscapularis muscle FI, not tendon integrity, correlates to anterior and central glenoid erosion. The study adds evidence that neither rotator cuff tendinopathy nor muscle atrophy exhibits a significant relationship to HSI.

Three-dimensional characterization of the anteverted glenoid (type D) in primary glenohumeral osteoarthritis

The Walch classification describes glenoid morphology in primary arthritis. As knowledge grows, several modifications to the classification have been proposed. The type D, a recent modification, was defined as an anteverted glenoid with or without anterior subluxation. Literature on the anteverted glenoid in primary osteoarthritis is limited. The purpose of this study, therefore, was to analyze the anatomic characteristics of the type D glenoid on radiographs and computed tomography (CT). The shoulder arthroplasty databases from 3 institutions were examined to identify patients with primary glenohumeral osteoarthritis and glenoid anteversion (≥5°), with or without anterior subluxation. The type D study cohort consisted of 18 patients (3% of the osteoarthritis cohort) and was a mean of 70 years old, with 11 women and 7 men. All radiographs were reviewed, and computed tomography Digital Imaging and Communications in Medicine (National Electrical Manufacturers Association, Rosslyn, VA, USA) data were analyzed on validated 3-dimensional imaging software. Rotator cuff fatty infiltration, glenoid measurements (anteversion and inclination), and humeral head subluxation according to the scapular plane were determined. In the study cohort, the mean glenoid anteversion was 12° (range, 5°-24°), the mean inclination was 0°, and the mean anterior subluxation was 38% (range, 6%-56%). Eight patients (44%) had a biconcave glenoid with a posterosuperiorly positioned paleoglenoid and an anteroinferiorly positioned neoglenoid, and 10 patients had a monoconcave glenoid. Fatty infiltration of the rotator cuff muscles never exceeded Goutallier stage 2. The type D glenoid is an addition to the original Walch classification and is characterized by glenoid anteversion (≥5°), anteroinferior humeral head subluxation, and absence of severe subscapularis fatty infiltration.

Rotator cuff muscles fatty infiltration increases with age: retrospective review of 210 patients with intact cuff on computed tomography arthrography

We aimed to demonstrate that rotator cuff fatty infiltration (FI) increases physiologically with age and that a FI degree of 2 might be encountered in patients with an intact cuff. We retrospectively evaluated the FI of 210 patients (classified in 7 age groups: <20, 20-30, 30-40, 40-50, 50-60, 60-70, and >70 years) who had an intact cuff on computed tomography (CT) arthrography. The Goutallier grading system was used to assess FI of rotator cuff muscles and of the deltoid muscle. FI was then compared between groups for each muscle, and determinants (age, sex, and body mass index) of FI were assessed. FI of all evaluated muscles progressively increased with age, but a statistically significant increase between 2 consecutive age groups was observed for all muscles only after age 40 years. For each group, intermuscle comparison showed that the FI distribution was not significantly different between each rotator cuff muscle at any age. Age was a determinant for FI for all muscles, but sex and body mass index also influenced deltoid FI. A median FI value of 2 was found in the "over 70 group" for the supraspinatus, but in the 60 to 70 group for infraspinatus and subscapularis and in the 50 to 60 group for the deltoid. FI of rotator cuff muscles increased with age, with a significant acceleration after 40 years. Moreover, a FI graded 2, a common threshold for management decision, was commonly found in those aging patients with intact cuff on CT arthrography.