Degeneration Of Rotator Cuff Muscles Research Articles

Rotator cuff muscle degeneration and tear severity related to myogenic, adipogenic, and atrophy genes in human muscle.

Large rotator cuff tear size and advanced muscle degeneration can affect reparability of tears and compromise tendon healing. Clinicians often rely on direct measures of rotator cuff tear size and muscle degeneration from magnetic resonance imaging (MRI) to determine whether the rotator cuff tear is repairable. The objective of this study was to identify the relationship between gene expression changes in rotator cuff muscle degeneration to standard data available to clinicians. Radiographic assessment of preoperative rotator cuff tear severity was completed for 25 patients with varying magnitudes of rotator cuff tears. Tear width and retraction were measured using MRI, and Goutallier grade, tangent (tan) sign, and Thomazeau grade were determined. Expression of myogenic-, adipogenic-, atrophy-, and metabolism-related genes in biopsied muscles were correlated with tear width, tear retraction, Goutallier grade, tan sign, and Thomazeau grade. Tear width positively correlated with Goutallier grade in both the supraspinatus (r = 0.73) and infraspinatus (r = 0.77), along with tan sign (r = 0.71) and Thomazeau grade (r = 0.68). Decreased myogenesis (Myf5), increased adipogenesis (CEBPα, Lep, Wnt10b), and decreased metabolism (PPARα) correlated with radiographic assessments. Gene expression changes suggest that rotator cuff tears lead to a dramatic molecular response in an attempt to maintain normal muscle tissue, increase adipogenesis, and decrease metabolism. Fat accumulation and muscle atrophy appear to stem from endogenous changes rather than from changes mediated by infiltrating cells. Results suggest that chronic unloading of muscle, induced by rotator cuff tear, disrupts muscle homeostasis. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:2808-2814, 2017.

Quantitative Analysis of Immune Cell Subset Infiltration of Supraspinatus Muscle After Severe Rotator Cuff Injury

Rotator cuff tears cause muscle degeneration that is characterized by myofiber atrophy, fatty infiltration, and fibrosis and is minimally responsive to current treatment options. The underlying pathogenesis of rotator cuff muscle degeneration remains to be elucidated, and increasing evidence implicates immune cell infiltration as a significant factor. Because immune cells are comprised of highly heterogeneous subpopulations that exert divergent effects on injured tissue, understanding trafficking and accumulation of immune subpopulations may hold the key to more effective therapies. The present study quantifies subpopulations of immune cells infiltrating the murine supraspinatus muscle after severe rotator cuff injury that includes tenotomy and denervation. Rotator cuff injury stimulates dramatic infiltration of mononuclear phagocytes, enriches mononuclear phagocytes in non-classical subpopulations, and enriches T lymphocytes in TH and Treg subpopulations. The combination of tenotomy plus denervation significantly increases mononuclear phagocyte infiltration, enriches macrophages in the non-classical subpopulation, and decreases T lymphocyte enrichment in TH cells compared to tenotomy alone. Depletion of circulating monocytes via liposomal clodronate accelerates supraspinatus atrophy after tenotomy and denervation. The study may aid rational design of immunologically smart therapies that harness immune cells to enhance outcomes after rotator cuff tears.

A semi-automated quantitative CT method for measuring rotator cuff muscle degeneration in shoulders with primary osteoarthritis

BackgroundRotator cuff muscle degeneration is an important parameter to consider when planning shoulder arthroplasty. HypothesisWe hypothesized that rotator cuff muscle degeneration is correlated with scapulohumeral subluxation in patients planned for anatomical total shoulder arthroplasty (TSA). Materials and methodsWe developed a semi-automated quantitative CT method to measure rotator cuff muscle degeneration, and retrospectively analyzed 107 preoperative shoulder CT scans of patients with primary osteoarthritis. On a standardized sagittal-oblique CT slice perpendicular to the scapular axis, two observers measured the cross-sectional areas of residual rotator cuff muscle tissues, normalized by the estimated area of healthy muscles. Muscle degeneration was quantified in a semi-automated manner, and divided into atrophy and fatty infiltration. Scapulohumeral subluxation was determined in 3D as the distance between the humeral head center and the glenoid surface center, projected on the same CT slice, and normalized by the humeral head radius. We tested all potential correlations between muscle degeneration and scapulohumeral subluxation. ResultsMuscle degeneration, primarily due to atrophy, predominated in the supraspinatus; it varied from 0.8% to 88.8%. Scapulohumeral subluxation varied from 2.5% to 72.9%, and was mainly in a posterior and postero-superior orientation. There was a significant but weak correlation between the amount of subluxation and both supraspinatus (R=0.207, P=0.032) and infraspinatus (R=0.225, P=0.020) degeneration. Inter- and intra-observer reproducibility of muscle degeneration measurements were both excellent (ICCs range=0.955–0.987 and 0.971–0.988, respectively). ConclusionThis new semi-automated CT method allows to quantitatively and reproducibly measure rotator cuff muscle degeneration in shoulders with primary osteoarthritis. Muscle degeneration is weakly correlated with scapulohumeral subluxation in patients planned for anatomical TSA. Level of evidenceLevel IV. Type of studyDiagnostic retrospective study.

Paper #36 - Histological quantification of chronic human rotator cuff muscle degeneration

Paper #36 - Histological quantification of chronic human rotator cuff muscle degeneration

Effect of tamoxifen on fatty degeneration and atrophy of rotator cuff muscles in chronic rotator cuff tear: An animal model study.

Fatty degeneration of the rotator cuff muscles is an irreversible change resulting from chronic rotator cuff tear and is associated with poor clinical outcomes following rotator cuff repair. We evaluated the effect of Tamoxifen, a competitive estrogen receptor inhibitor, on fatty degeneration using a mouse model for chronic rotator cuff tear. Sixteen adult mice were divided into two diet groups (Tamoxifen vs. Regular) and subjected to surgical creation of a large rotator cuff tear and suprascapular nerve transection in their left shoulder with the right shoulder serving as a control. The rotator cuff muscles were harvested at 16 weeks and subjected to histology and RT-PCR for adipogenic and myogenic markers. Histology showed substantially decreased atrophy and endomysial inflammation in Tamoxifen group, but no significant differences in the amount of intramuscular adipocytes and lipid droplets compared to the Regular group. With RT-PCR, the operated shoulders showed significant upregulation of myogenin and PPAR-γ, and downregulation of myostatin compared to the nonsurgical shoulder. No significant differences of gene expression were found between the two diet groups. Our study demonstrated that tamoxifen diet leads to decreased muscle atrophy and inflammatory changes following chronic rotator cuff tear, but has no apparent effect on adipogenesis.

Progression of fatty degeneration of rotator cuff muscles after cuff repairs

Progression of fatty degeneration of rotator cuff muscles after cuff repairs

Fatty degeneration of the rotator cuff muscles on pre- and postoperative CT arthrography (CTA): is the Goutallier grading system reliable?

To retrospectively evaluate fatty degeneration (FD) of rotator cuff muscles on CTA using Goutallier's grading system and quantitative measurements with comparison between pre- and postoperative states. IRB approval was obtained for this study. Two radiologists independently reviewed pre- and postoperative CTAs of 43 patients (24 males and 19 females, mean age, 58.1years) with 46 shoulders confirmed as full-thickness tears with random distribution. FD of supraspinatus, infraspinatus/teres minor, and subscapularis was assessed using Goutallier's system and by quantitative measurements of Hounsfield units (HUs) on sagittal images. Changes in FD grades and HUs were compared between pre- and postoperative CTAs and analyzed with respect to preoperative tear size and postoperative cuff integrity. The correlations between qualitative grades and quantitative measurements and their inter-observer reliabilities were also assessed. There was statistically significant correlation between FD grades and HU measurements of all muscles on pre- and postoperative CTA (p<0.05). Inter-observer reliability of fatty degeneration grades were excellent to substantial on both pre- and postoperative CTA in supraspinatus (0.8685 and 0.8535) and subscapularis muscles (0.7777 and 0.7972), but fair in infraspinatus/teres minor muscles (0.5791 and 0.5740); however, quantitative Hounsfield units measurements showed excellent reliability for all muscles (ICC: 0.7950 and 0.9346 for SST, 0.7922 and 0.8492 for SSC, and 0.9254 and 0.9052 for IST/TM). No muscle showed improvement of fatty degeneration after surgical repair on qualitative and quantitative assessments; there was no difference in changes of fatty degeneration after surgical repair according to preoperative tear size and post-operative cuff integrity (p>0.05). The average dose-length product (DLP, mGy·cm) was 365.2mGy·cm (range, 323.8-417.2mGy·cm) and estimated average effective dose was 5.1mSv. Goutallier grades correlated well with HUs of rotator cuff muscles. Reliability was excellent for both systems, except for FD grade of IST/TM muscles, which may be more reliably assessed using quantitative measurements.

Efficacy of Marrow-Stimulating Technique in Arthroscopic Rotator Cuff Repair: A Prospective Randomized Study (SS-14)

To evaluate the efficacy of marrow-stimulating technique by microfracturing greater tuberosity during arthroscopic rotator cuff repair. The hypothesis of the study was that microfractures can improve outcome of rotator cuff repair. Eighty patients with a full-thickness tear of the posterior-superior rotator cuff underwent an arthroscopic repair. All procedures were performed by using single-row repair technique with metal suture anchors alone or combined with side-to-side repair. Patients were divided in two groups of 40 cases each. In group 1, standard repair was performed; in group 2, microfractures of the greater tuberosity were performed to enhance tendon repair. Exclusion criteria were: partial-thickness and irreparable cuff tears, subscapularis tears, labral pathology, os acromiale, degenerative arthritis of glenohumeral joint, symptomatic arthritis of acromioclavicular joint, rotator cuff arthropathy, previous surgery to the same shoulder, and workers' compensation claims. Sample size was calculate in order to achieve power equal to 0.80. Results were evaluated at minimum two-year follow-up. Clinical outcome was assessed using the DASH self-administered questionnaire (primary outcome) and the Constant score normalized for age and gender. Structural integrity of repaired tendons was evaluated with MRI. The following independent variables were considered: age, gender, dominance, type of work, timing of symptoms, size, shape and retraction of the cuff tear, fatty degeneration of rotator cuff muscles, treatment of the biceps tendon, repair technique (anchors or anchors and side to side), and number of anchors. Matched-pair comparison was performed for each independent variable. Comparisons between groups for clinical outcomes were adjusted for baseline values. Multivariate linear and logistic regression analysis was performed to determine which variables were independently associated with the outcome. Significance was set at p < .05. Mean follow-up was 28 months. Seven patients were lost at follow-up (2 patients in group 1, and 5 in group 2, respectively). Comparison between groups did not show significant differences for each independent variable. Mean DASH score was 28.6 points in group 1 and 23.3 points in group 2. Mean normalized Constant score was 92.7 points in group 1 and 94.5 points in group 2. Differences between groups were not significant. Tendon healing rate assessed by MRI was 52.6% (20/38) in group 1 and 65.7% in group 2, without significant difference between groups. However, stratified analysis for size of cuff tear showed that group 2 had significantly greater healing rate than group 1 for large tears (p = 0.040). Multivariate analysis showed that age, gender, timing of symptoms, tendon retraction and fatty degeneration significantly and independently affected clinical outcomes. Influence of microfractures on healing rate of repaired tendons approximated to significance (p = 0.07). Marrow-stimulating technique by microfracturing greater tuberosity during arthroscopic rotator cuff repair did not influence clinical outcome, but significantly improved healing rate of large rotator cuff tears.

Will Preoperative Atrophy and Fatty Degeneration of the Shoulder Muscles Improve after Rotator Cuff Repair in Patients with Massive Rotator Cuff Tears?

Recently, retear rate after repair for massive cuff tear have been improved through devised suture techniques. However, reported retear rate is relevant to preoperative atrophy and fatty degeneration. The purpose of this study was to investigate whether preoperative atrophy and fatty degeneration of rotator cuff muscles improve by successful repair. Twenty-four patients with massive rotator cuff tear were evaluated on the recovery of atrophy and fatty degeneration of supraspinatus and infraspinatus muscle after surgery. Atrophy was classified by the occupation ratio and fatty degeneration by modified Goutallier's classification. Both were assessed on magnetic resonance imaging (MRI) before and after the operation. When the cuff was well repaired, improvement of the atrophy and fatty degeneration were observed in a half and a one-fourth of the cases, respectively. In retear cases, however, atrophy and fatty degeneration became worse. Improvement of atrophy and fatty degeneration of the rotator cuff muscles may be expected in the cases with successful achievement of rotator cuff repair for large and massive tear.

Evaluation of Fatty Degeneration of the Supraspinatus Muscle Using a New Measuring Tool and Its Correlation Between Multidetector Computed Tomography and Magnetic Resonance Imaging

Background: The assessment of fatty degeneration of rotator cuff muscles with a reliable grading system is very important. However, there is no generally accepted tool to measure it quantitatively. Purpose: This work was undertaken to introduce a new method to evaluate fatty degeneration by calculating the occupation ratio of the supraspinatus, to determine the correlation between this occupation ratio and the degree of Goutallier’s fatty degeneration or tear size of rotator cuff muscles and to assess the correlation between multidetector computed tomography (MDCT) and magnetic resonance imaging (MRI) using this new measuring tool. Study Design: Cohort study (diagnosis); Level of evidence, 2. Methods: Sixty-one patients with full-thickness rotator cuff tears who had undergone arthroscopic rotator cuff repair were included. The occupation ratio was measured using the magic selection tool in Photoshop on MDCT and both T1- and T2-weighted oblique sagittal magnetic resonance images of Y-view. One-way analysis of variance was used to determine the association between this occupation ratio and the degree of fatty degeneration as assessed by Goutallier’s method. The correlation between the occupation ratio and tear size, and the correlation of the occupation ratio between MDCT and MRI, were evaluated using the Pearson correlation coefficient. In addition, the interobserver and intraobserver reliabilities of this measuring tool were assessed on each image by 2 orthopaedic surgeons and analyzed using interclass correlation coefficients. Results: Comparison of the occupation ratio measured by this new method with the Goutallier grade of fatty degeneration on MDCT and MRI revealed a highly significant correlation, with all P values < .001. Also, comparison of this new occupation ratio and cuff tear size showed a reverse correlation on MDCT, T1-weighted magnetic resonance images, and T2-weighted images, with Pearson correlation coefficients of −.61, −.56, and −.50 (all P < .001) by rater 1, and −.57, −.53, and −.43 (all P < .001) by rater 2. Comparison of the occupation ratio between MDCT and MRI demonstrated significant correlation, with Pearson correlation coefficients of .78 and .87 between MDCT and T1-weighted magnetic resonance images and .73 and .82 between MDCT and T2-weighted images. The interobserver and intraobserver reliabilities of this new measuring tool on MDCT and both T1- and T2-weighted magnetic resonance images were excellent in all images, with interobserver correlation of .89, .92, and .91 and intraobserver correlation of .89 and .96, .90 and .98, and .85 and .97, respectively. Conclusion: This new quantitative measuring tool to evaluate the fatty degeneration of rotator cuff muscles was reliable and correlated well with both the preexisting grade of fatty degeneration and cuff tear size. Also, there was a significant correlation between oblique sagittal images of MDCT and MRI using this method; therefore, MDCT can be another option for imaging modality, comparable with MRI, for the evaluation of fatty degeneration of rotator cuff muscles.

Reliability of the Grading System for Fatty Degeneration of Rotator Cuff Muscles

Fatty degeneration of the rotator cuff muscles is considered one of the most important factors for the outcomes of cuff repair. However, the reliability of the grading system is not well validated. Two specialists in musculoskeletal radiology and three shoulder fellowship-trained orthopaedic surgeons reviewed the fatty degeneration grades of each cuff muscle of consecutive 75 full-thickness cuff tears. Fatty degeneration grades were assessed according to the systems of Goutallier et al. and Fuchs et al. using preoperative MR and postoperative CT arthrographies. The interclass correlation coefficient was analyzed to assess interobserver and intraobserver reliabilities. For interobserver reliability using the system of Goutallier et al. the interclass correlation coefficient was higher in MR arthrography (0.6-0.72) than in CT arthrography (0.43-0.6) and higher for radiologists (0.58-0.78) than for orthopaedic surgeons (0.32-0.68). There was no difference between the systems of Goutallier et al. and Fuchs et al. Intraobserver reliabilities showed a similar pattern (0.26-0.81), but the level of experience should be considered. Although the system of Goutallier et al. is most widely used in orthopaedics, reported data should be interpreted carefully because of the relatively low reliability. Level III, diagnostic study. See the Guidelines for Authors for a complete description of levels of evidence.

Quantitative Assessment of Fatty Degeneration in Rotator Cuff Muscles Determined With Computed Tomography

Reliable assessment of fatty degeneration of rotator cuff muscles is desirable to predict the outcome of shoulder surgery. Currently used qualitative assessments are limited by relatively high inter- and intraobserver variability. It was hypothesized that a quantitative measurement of muscle density using computed tomography (CT) was more reliable and reproducible. Thirty shoulders from patients with rheumatoid arthritis were analyzed using parasagittal multiplanar reconstructions acquired from a 16-slice CT scanner. Three observers visually rated the severity of fatty degeneration and independently outlined the rotator cuff muscles, after which the mean density was calculated. Inter- and intraobserver agreement on both measurements was expressed by the interclass correlation coefficient (ICC) and the standard deviation of the differences (SDD) between the measurements. A strong correlation was found between the quantitative measure and the visual rating (R2 = 0.94; P < 0.0001). The SDD in muscle density did not exceed 2.3 Hounsfield units, and the mean rotator cuff ICC (0.98) was substantially greater than that of the visual rating (0.63). This study describes a reproducible method to quantify fatty degeneration of the rotator cuff muscles in CT images, with a higher interobserver agreement than the visual score, and may prove a reliable tool to evaluate the quality of the rotator cuff muscles.

Investigations of complete rotator cuff tears with the fatty degeneration of rotator cuff muscles

Investigations of complete rotator cuff tears with the fatty degeneration of rotator cuff muscles